Chapter - 2

Review of Literature

The vegetables are very important for human dietary, among all the

vegetables, Chilli, Brinjal, Tomato and Okra are consumed maximum and are

being grown widely. Vegetables are rich in carbohydrates, proteins, fats and

vitamins. These crops are also grown widely in Karnataka. These crops are

affected by a number of fungal, bacterial, viral and nematodal diseases. These

diseases reduce yield loss to crops. Wilt, leaf spots, damping -off, rusts, leaf curl,

mosaic, blights, canker, rots, brooms, die-back or fruit-rots and anthracnose leaf

spots are the common diseases caused by the fungal pathogens. Some of these

pathogens are seed borne and they transmit the diseases to the newer area or seed

to subsequent crops. Many workers have reported seed transmission studies in

different crops. Some of the important diseases are recorded (Table 2.1, 2.2, 2.3

and 2.4).

2.1. Screening and detection

Asalmol et al. (2001) have revealed the incidence and the extent of fungi

associated with different varieties of chilli seeds from Maharastra State Seed

Corporation, using standard blotter test. They have recorded the Aspergillus

flaviis, Rhizopus stolaniferae, Fusarium moniliformae, Colletotrichum capsici and

Aspergillus niger at the range of 11.56 to 31.42 per cent. They have also studied

their significant effect on pre-emergence as well as post- emergence mortality.

21

Table 2.1. Common diseases of Capsicum annum L.

SI. No. Disease Casual organisms(s) Reference

1. Die-back or ripe fruit Colletotrichum capsici (Syd.) Butl. Kumar and off and Bisby Dwivedi(1999)

2. Phytophthora blight Phytophthora capsici Leon 3. Bacterial leaf spot Xanthomonas compestris pv.

Vesicatorium (Doidge) Dye 4. Fusarium wilt Fusarium solani (Mart.) Snyder and

Hansen 5. Sclerotium disease Sclerotium bataticola Taub. 6. Pythium fruit-rot Pythium debaryanum Hesse 7. Choaneophora blight Choaneophora

cucurbitarum (B. and Rav.) Thaxter 8. Cercospora leaf-spot

(Frog eye leaf spot) Cercospora capsici Heald and Wolf

9. Black spot (leaf spot) Alternaria solani (Ell. and Mart.) Jones and Groul

10. Mosaic disease (leaf curl)

Virus

11. Phoma rot Phoma destructiva Plowr. 12. Brown-Rot Bacterium solanacearum EFS. 13. Gray Mold-Rot Botrytis sp. 14. Bacterial soft rot Erwinia carotovorus (Jones). Bergey

etal. 15. Southern Sclerotium

(dry rot) Sclerotium rolfsii Sacc.

16. Phomopsis blight Phomopsis capsici (Mag.) Sacc. 17. Damping-off Pythium aphanidermatum

Rhizoctonia solani (Eds.) Fitz. Kuhn. 18. Leaf spot Cercospora capsici Heald and Wolf .

19. Powdery mildew Leveillula taurica (lev.) Solmon 20. Stem rot Macrophomina phaeseolina 21. Root-knot Meloidogyne javanica (Taub.)

chitwood 22. Blossom-end rot Physiological disorder 23. Simscald Physiological disorder 24. Skin cracking Physiological disorder 25. Flower and fruit drop Physiological disorder 26. Fruit rot Phytophthora capsici Leonian E.F.

Smith 27. Bacterial wilt Pseudomonas solanacearam 28. Leaf curl. Virus 29. Pepper ring spot Virus

Source : Charles Chupp (1994).

22

Table 2.2. Common diseases of Solanum melongena L. SI. No.

Disease Casual organisms Reference

1. Phomopsis blight Phomopsis vexans (Sacc. and Syd.) Harter 2. Verticillium wilt Verticillium alboatrum Reinke and Berth 3. Bacterial wilt Pseudomonas solanacearum E.E. Smith 4. Anthracnose Colletotrichum sp. 5. Cercospora leaf-spot Cercospora melongenae C. solani Welles

dethuemen 6. Gray mold-rot Botrytis sp. 7. Rhizoctonia fruit and

stem rot Corticium vagum B. and C.

8. Nectria stem-rot Nectria ipomaceae Hals. 9. Phytophtliora fruit spot Phytophthora melongenae Sawada 10. Black dot-rot Rhabdospora melongenae Han. 11. Macrosporium leaf spot Macrosporium solani E. and M. 12. Root-knot Meloidogyne javanica (Mont.) De Bary 13. Phytophthora blight Phytophthora infestans 14. Septoria leaf spot Septoria lycopersici Speg. 15. Leaf spots Alternaria melongenae Rang and Samb. Mohit Singh

A. solani (Ell. and Mar.) Jones and Grout and Shukla Cercospora solani Chupp.de thuemen. Melongenae Barclay, C. solani

(1986)

16. Rust Pucciniapenniseti (Mart). App. and Wollenw.Sacc.

17. Wilts and root rots Macrophominaphaseolina E.F. Sm. Fusarium solani Sclerotium rolfsii Pseudomonas solanaceatum

18. Little leaf Mycoplasma 19. Calyx withering Physiological disorder 20. Poor fruit set Physiological disorder 21. Damping-off Pythium debaryanum

Rhizoctonia solani Verticillium albo-atrum Phytophthora spp.

22. Powdery mildew Laveillula taurica (lev.) Am. Phyllactina moricola (P. Herm.)

23. Mosaic disease Alfalfa mosaic virus 24. Fruit rot Rhizopus nodosus Vyas et al.

(1978) 25. "Wilt and Fruit rot Fusarium semitectum Kaur et al.

(1985) 26. Leaf blight Fusarium equisetii * Bilgrami

etal. (1919)

Source : Charies Chupp (1994).

23

Table 2.3. Common diseases of Lycopersicum esculentum Mill. SI. No.

Disease Casual organisms Reference

1. Septoria leaf spot Septoria lycopersici Speg Sugha and Suman Kumar (2000)

2. Macrosporium blight and rot

Macrosporium spp.

3. Leaf mould Cladosporium fulvum Cooke 4. Mosaic disease Undetermined 5. Damping-off Pythium aphanidermatum

(Ed.S.) Fitz. 6. Grand rapid disease Aplanobacter michiganense

E.F.S. 7. Streak disease Bacillus lathyri M and T 8. Brown-rot Bacterium solanacearum EFS 9. Fusarium wilt Fusarium lycopersici (Sail) 10. Western yellow-blight Fusarium sp. 11. Ascohyta blight Didymella lycopersici (Brun.)

klebahn. 12. Collar rot Verticillium lycopersici P. and

P. et al, 13. Timber-rot Sclerotinia liberitana Fekl. 14. Botrytis stem rot Botrytis sp. 15. Southern sclerotium rot Sclerotium rolfsii Sacc 16. Phoma rot Phoma destructiva Plowr. 17. Buck eye-rot Phytophthora infustans, var. Sharma et al. (1978)

parasitica 18. Anthracnose Colletotrichum phomoides

(Sacc.) Chester 19. Tospora rot Fospora lactis-parasitica

Pritchard and Porte 20. Melanconium fruit rot Isaria clonostachoides

Melanconium sp. Prit and Porte 21. Yeast rot Nematospora lycopersici

Schneider 22. Crown-gait Bacterium tumefaciens EFS

and Town send 23. Early blight Alternaria solani (Ell. and

Mrt.) Jonei and (Mont) de bary. Grout. (Sacc.) Snyder and Hansen

24. Late blight Phytophthora infestans 25. Wilt Fusarium oxysporum 26. Bacterial wilt Pseudomonas solanacearum

E.F. Smith Contd.

24

27. Fruit rot Pytophthora infestans (Mont.)de Bary P. palmivora Butler P. parasitica Dast Fusarium spp. (Ell and Mart). Alternaria solani Jones and Grout., Rhizopus sp., Erwinia spp.

28. Stem and Fruit canker Corynebactereum michiganense (E.F.Sm.) Jensen.

29. Root-knot Meloidogyne javanica (Traub.) chitwood

30. Spotted wilt Virus 31. Bunchy stant

(Bunchy tap) Mycoplosma

32. Leaf curl Virus 33. Aucuba mosaic Virus 34. Big bud Mycoplasma 35. Powdery mildew Leveillula taurica (lev.j Arn 36. Root rot Macrophomina phaseolina 37. Wilt Sclerotium rolfsii. Sacc. 38. Bacterial leaf spot Xanthomonas veslcatoria

(Doidge). Dowson 39. Blossom end rot Physiological disorder 40. Fruit cracking Physiological disorder 41. Sunscald Physiological disorder 42. Puffiness Physiological disorder 43. Cafface Physiological disorder 44. Low temperature injury Physiological disorder 45. Delayed ripening and

colour development Physiological disorder

46. Gold Fleck Physiological disorder 47. Silvering Physiological disorder 48. Pithy stem Physiological disorder 49. Oedema or Saropsy Physiological disorder 50. Crease-stem Physiological disorder 51. Verticillium wilt Verticillium dahhiae Kreb 52. Bacterial Speck Pseudomonas syringe (Okabe)

Young. Dye and Wilkie 53. Fruit rot Cladosporium oxysporum Sher Singh et al.

(1983) Cladosporium tenuissimum Avdesh Narain &

Rout (1981)

Source : Charles Chupp (1994).

25

Table 2.4. Common diseases of Abelmosc/tus esculentus (L.) Moench. SI. No.

Disease Organisms (s) Reference

1. Fusarium wilt Fusarium oxysporum f sp. vasinfectum Fusarium chlamydosporum

2. VerticilUum wilt VerticilUum alboatrum Reinke and Berth

3. Ascochyta pod-spot Ascochyta abelmoschi Harter 4. Texas Root-rot Ozanium omnivorum Shear 5. Root-Knot Heterodera radicicola (Greef)

Isill 6. Grey Mold rot Botrytis sp. 7. Vein clearing disease Virus (vector-Bemisia tabaci) 8. Powdery mildew Erysiphe lichorarearums DC. 9. Cercospora leaf spots Cercospora malayensil Solh and

SV. C. abelmoschi Ell and EV 10. Damping off

Cercospora malayensil Solh and SV. C. abelmoschi Ell and EV

11. Fruit rot Pythium rudicum Balkr 12. Leafspot Alternaria sp. 13. Rust Uromyces heterogeneus Cke 14. Anthracnose Loll etotrichemy spp. 15. Poor seed germination Physiological disorder 16. Root rot Rhizoctonia solani Kuhn. 17. Bacterial leaf spot Xanthomonas campestris

(Rangaswami and Eswaran) Dye 18. Collar rot Macrophomina phaeseolina Jha and Dubey

(2000) Source : Charles Chupp (1994).

26

Bhartiya et al. (2000), Suryanarayana and Bhombe (1961) have studied the

mycoflora of vegetable crops. Prasad et al. (2000) studied the mycoflora of chilli

collected from different parts of India, exhibited varying degrees of decay with

respect to discolouration and breaking of the pericarp, detachment of the pedicel

and spore dust formation within the fruit. Aspergillus flavus, Aspergillus terreus,

Aspergillus candidus, Aspergillus niger, A. sclerotiarum, Fusarium moniliformae,

F. sporotrichoides, Syncephalastrum racemosum, Paecilomyces varioti and

Penicillium corylophilum were common storage fungi in association with

decaying chilli fruits stored in humid region. They have studied the effect of

storage moulds on capsaicin content that was decreased due to infection.

Bhale et al. (2000) have studied the Colletotrichum dematium in chilli

seeds. They have compared the different seed health testing methods and found

modified deep freeze blotter was the superior to other methods and it has enabled

to detect 31 per cent C. dematium from the seeds. The fungus was found

responsible for seed rot, seedling decay, die back and fruit rot. Usha Bhale et al.

(2000) have also recorded the 16 fiingi found associated with 36 seed samples of

chillies, Colletotrichum dematium and Alternaria alternata are dominant. Standard

blotter method was better than agar plate method as it could detect 18 fungi as

compared to 6.0 per cent in agar method.

Giridhar and Reddy (1999) reported incidence of mycotoxigenic fungi on

red pepper. The mycoflora and percentage of toxigenicity varied with the sample

and geographical location. Aspergillus fumigatus and Aspergillus ochraceus were

highest than Aspergillus flavus.

Al Kassim (1996), for the first time in Saudi Arabia, has studied the seed

mycoflora of locally cultivated okra, capsicum, and seeds were obtained from the

local market and farmers field. A total of 15 species of fungi was belonging to the

27

genera Alternaria, Aspergillus, Botrytis, Cladosporium, Colletotrichum,

Curvularia, Epicoccum, Fusarium, Penicillium and Stemphylium.

Prabhavathy and Reddy (1995) recorded Black rot disease on chilli fruits

collected from various markets in the Warrangal district, Andhra Pradesh, found to

be 3 species of fungi Alternaria alternata, Curvularia lunata and C. pallescens,

Pythium butleri, Botryodiploidia theobromae, Phomopsis equisetii, Rhizopus

stolaniferae, Fusarium semitectum and Choanephora cucurbitarum. This is the

first report from this region. Devi and Singh (1999) also reported a severe

anthracnose of chilli from Imphal, Manipur, causing 80% seedling mortality, the

fungi were identified as C. gloeosporioides {Glomerella cingulata).

Gupta and Basuchoudhary (1995) have reported the bhindi, brinjal and

chillies seed mycoflora. The fiingi recorded were Alternaria alternata, Aspergillus

spp., Chaetomium spp., Colletotrichum dematium, Curvularia lunata, Drechslera

spp., Fusarium spp., Mucor spp., Penicillium spp. and Rhizopus spp. These fungi

caused pre and post emergence mortality of seedlings. For the first time, in India

they have reported of Fusarium pallidoroseum and Drechslera australiensis in

brinjal.

Sharma and Sumbali (1993) have surveyed markets vegetables to evaluate

the post-harvest fungal decay of various vegetables. They have reported 36 species

belonging to 23 genera were isolated and of these moniliales topped the list with

26 species of 17 genera. Many of these fungi were new records in India.

Okoli and Erinle (1990) have studied Fusarium equisetii, F. oxysporum,

Fusarium chlamydosporum, Exserpohilum vestratum (Setosphaeria rostrata),

Rhizopus stolaniferae, Colletotrichum capsici, Geotrichum candidum, Curvularia

lunata (Cochliobolus lunatus) and Aspergillus niger, where highly significant

difference was found in the rate of rot induction to tomato fruits.

28

Rath et al. (1990) reported phytopathological analysis of 264 samples of

rotten tomatoes collected from markets in 7 localities in Orissa during 1986-89.

They have reported 11 fungal species belonging to 9 genera and of these, rot

caused by Chaetomium brasiliense and Monascus ruber that are new records for

India.

Mridha and Siddique (1988) reported, Colletotrichum capsici and Fusarium

moniliformae were found pathogenic to chilli. The associations of Alternaria

tenuis, Colletotrichum capsici, Curvularia lunata and Fusarium moniliformae

with the seeds collected from different types of infected fruits and seeds collected

from different sources established a relationship between the fruit infection and

seed infection. The progressively higher infection of all the four seed-borne fungi

with least infected fruits to the highest infected fruits clearly indicates a positive

correlation between fruit infections and seed infection.

Deena and Basuchoudhary (1984) and Uma Pandey (1976) have studied the

seed mycoflora of chilli from 20 seed samples. Gupta et al. (1983) have studied

mycoflora of chilli and recorded 26 fungi, 7 bacterial isolates and 8 isolates of

actinomyces, using SBM method and Gupta et al. (1980) also reported the

microflora of summer chilli. Out of 41 microorganisms, 26 forms of fungi, 8 forms

of actinomycetes, and 7 forms of bacteria. Among all the mycoflora reported,

Alternaria solani is serious pathogen to the chilli crop and causes leaf blight

during summer crop.

2.2. Epidemiology

Epidemiology of disease is a study of the factors affecting the outbreak of

infectious diseases. Many researchers have worked on the epidemiology of chilli,

brinjal, tomato, and okra crops in different regions of the country. Sugha et al.

(2002) reported the effect of temperature, relative humidity, fruit age, inoculum

29

age, inoculum load and repeated sub-cultured inoculum was ascertained on the

development of Phomopsis fruit rot of brinjal by Phomopsis vexans. The

temperature of 25° C, RH>90%, fruits of younger age (5-10 day old), higher

inoculum load (>120 spores/ml) and inoculum of younger age (14 day old) were

found conducive for the development and progress of Phomopsis fruit rot.

Repeated sub-culturing of inoculum resulted in loss of aggressiveness of the

pathogen.

Adarsh Pandey and Pandey (2001) have reported Cladosporium fulvum,

Helminthosporium spiciferum, Trichothecium roseum, Fusarium solani,

Alternaria tenuis, Chaenophora cucurbitarum and Curvularia lunata encountered

either parasiting leaves or fruits. The survey was made primarily for preparing a

disease calendar for Bareilly brinjal crop.

Kamlesh Mathur and Gurjar (2001) reported the severe mortality of chilli

during March-April in Jaipur. Isolations from diseased portion invariably yielded

Sclerotium rolfsii and pathogenecity of the fungus was proved on healthy chilli

seedlings grown in inoculated soil in pots. The symptoms developed within

5 days, the fungus grown actively only in moist soil at moderate to high

temperature (30-35°C).

Kanjilal et al. (2000) reported the disease potential of hybrid and deshi

(indigenous) cultivars of tomatoes were conducted in Coochbehar, Jalpaiguri,

Nadia and Murshidabad districts of West Bengal. Results showed that heavy

disease incidence on hybrid as compared to deshi cultivars. Predominant diseases

of hybrid cultivars were bacterial wilt caused by Ralstonia solanacearum, leaf curl

by virus. The diseases of blight caused by Phytophthora and Alternaria. The field

disease incidence of hybrid cultivars were severe in North Bengal acidic sandy

soils than in nearly neutral loam soil of Nadia and Murshidabad districts.

30

Karegowda et al. (2000) reported the tomato wilt pathogen Fusarium oxysporum

sp. lycopersici. It is highly specific to tomato and primarily it is soil inhabiting.

Rekha et al. (2000) have studied the crown and root rot of tomato by

Fusarium oxysporum f. sp.. basilici, the causal agent of Fusarium wilt. The role

of the air borne propagules in the epidemics of the disease in tomato plants was

studied. In the field, airborne propagules of F. oxysporum f sp. radicis-lycopersici

were trapped with a selective media and their prevalence was determined. Plants

grown in both covered and uncovered pots, detached from the field soil and

exposed to natural aerial inoculum developed typical symptoms (82 to 87%

diseased plants). The distribution of inoculum in the growth medium in the pots

also indicated.

Sugha and Suman Kumar (2000) reported role of inoculum load, host

extracts, leachates, dew and leaf wetness was determined on the development of

Septoria leaf spot {Septoria lycopersici speg.) of tomato (Lycopersicon

esculentum Mill.). An increase in inoculum accelerated the progress of disease

development. Inoculum load of 525-1050 spores ml'' and leaf witness in the range

of 48-60 h were found optimum for normal development of disease under artificial

inoculation test.

Jha and Dubey (2000) surveyed eight different localities of Ranchi revealed

the occurrence of the collar rot disease of okra. The incidence of the disease

ranged from 12.7 to 58.3% by Macrophominaphaseolina. Although the pathogen

grew on a wide range of pH (4.0-8.0), the pH range of 6.0-7.0 was the optimal.

The occurrence of the disease appears to be a new record from this region.

Kumar and Sugha (1999) reported progressive increase in the age of

pycnidia of Septoria lycopersici, an incitant of leaf spot of tomato resulted in

decreased germination of spores. Spores remain viable upto 6 months after harvest

on plant debris stored under laboratory and green house conditions. Plant debris

buried near the soil surface and disease infested soil helped in the over seasoning

of the pathogen and successful initiation of disease.

Bhale et al. (1999) reported the severity of chilli seed rot, seedling decay,

twig blight and fruit rot by Colletotrichum dematium was found responsible for

severe seed rot, seedling decay, twig blight and fruit rot in chillies. The

pathogenecity of the isolated fungus was tried by six methods on ripe, semi ripe

(turning red stage) and leaves under laboratory and field conditions. The methods

are pinprick (PP), carborandum rub (CR), spore suspension spray (SSS), dip

(SSD), injection (SSI) and tooth prick prick (TPP). The spore suspension

C. dematium was obtained by addition of 10 ml of sterile water in 12 days old

culture growing on PSA in 30-ml test tubes. Among the methods, the pin prick

method (PP) was the best in which typical symptoms under detached conditions

developed on semi-ripe and fully ripe fruits. Ripe fruits, were more susceptible

than semi ripe, the pin prick method was also effective in leaf inoculation, the

injury to fruits and leaves.

Yael Rekh et al. (1999) reported the spatial distribution and temporal

development of tomato crown and root rot caused by Fusarium oxysporum f sp.

radicis-lycopersici were studied in naturally infested fields in 1996 and 1997.

Geostatical analysis and semivariogram calculations revealed that the disease

spreads from infected plants to a distance of 1.1 to 4.4 m during the growing

season. By using a chlorate - resistant nitrate non utilizing (nif) mutant of

F. oxysporum f. sp. radicis-lycopersici as a "tagged" inoculum, the pathogen was

found to spread from one plant to the other due to the infection of the roots. The

pathogen spread to up to four-plant (2.0 m) on either side of the inoculated focus

plant. Root colonization by the nif mutant showed a decreasing gradient from the

site of inoculation to both sides of the inoculated plant.

32

Dubey and Jha (1999) reported "collar rot" caused by Macrophomina

phaseolina in Bihar, The field trials were laid out in randomized block design with

plot size of 4.5 sqm. using okra variety "Prabhani kranti" sown at 2 weeks

intervals starting from 1̂ ' January to 17"' December during 1994 and 1995. Seeds

sown during 9 April to 1^ May for summer crop resulted maximum germination

(61,3-82.7%), minimum pre-emergence (6.0-18.0% and post-emergence

(2,8-11.6%) mortality. The average temperature (22.2-26,2°C), relative humidity

(42.3-51,8%) and rainfall (0,0-7.4 mm) during timely summer season sown crop

between 12 to 26 March favoured maximum disease development. Similarly,

average temperature (25.7-35.TC), relative humidity (50.0 - 84.8%) and rainfall

(18.1-16.9 mm in 1994 and 5.0 - 57.2 mm in 1995) during rainy season crop

between 4"̂ to 18*'̂ June also favoured the maximum disease development. High

rainfall during July and low temperature prevailed during winter season did not

favour the disease development.

Cerkauskas et al. (1999) reported powdery mildew on cvs. Oberon and

triple 4 of green house pepper {Capsicum annum) and cv. fireflame of chilli in

Reamington and Vineland, in Southern Ontario, Canada. Yield losses recorded

was 10-15%. The disease symptoms and fungal morphology was confirmed by

inoculation of 41 days old green house pepper cvs. Cubico and Edison and 58 days

old field pepper cv. Ranegade. Occurrence of the fungus on the abaxial surface of

pepper foliage, presence of endophytic mycelium and the morphological

characteristics of the imperfect state confirmed the identity of the fungus.

Fugro (1999) observed during the rainy season, a severe out-break of stem

canker in okra cv. Arka anamika at the central experiment station, Wakawali,

Maharashtra, India. Dark brown to black, circular to elongated lesions developed

on the stem of young okra seedlings. Many infected seedlings girdled at the point

of infection, which ultimately, led to death of the seedlings. Under rainfall and

33

humid conditions, many infected plants showed splitting of the bark exposing

inner cortex tissues. The leaf petioles, flower buds, calyx and immature pods were

also infected showing small, circular to elongated dark brown lesions. The causal

agent was isolated and identified as Fusarium chlamydosporum and its

pathogenecity was confirmed.

Jha and Dubey (1998) reported highly susceptible Okra cv. "Prabhani

kranti", sown in sick plot, to determine the highly susceptible age of plants for

infection and disease development. Sick plot was developed by artificially

incorporation of inoculum developed on sand corn meal medium and cultivation

of several crops of highly susceptible variety. Three locations in the fields were

selected for observations. 21 days old plants were highly susceptible to infection

and showed maximum disease incidence followed by 14-20 days old plants during

both the years. After 21 days, disease incidence decreased gradually and 77 days

old plants did not get infection. The average temperature (24.3-25.5°C), relative

humidity (RH) (42.5-50.7%) and rainfall (0.9-0.24 mm) during 1994 and 1995

were favourable for disease development in 21 days old plants.

Vyas et al (1978) have reported the soft-rot disease of brinjal {Solarium

melangena Linn.) fruits caused by Rhizopus nodosus. The disease starts as soft rot

from the mesocarp portion of the brinjal fruit. The fungus multiplies inside the

fruit, causing discolouration and rotting of the healthy tissues. The skin becomes

loose and tissues sunken with considerable depression.

Singh et al. (1997) have studied the marginal leaf blight of brinjal by

Fusarium equisetti in the nursery of Valley Fruit Research Station, Srinagar-

Garhwal. In initial stage, yellow to light brown spots developed on the foliage or

near the leaf margins and leaf lamina. Histopathological studies indicated that the

necrotic areas of stem showed discolouration of cortical tissues and the yellowish

brown mycelium extended upto the pith region. In artificially inoculated plants,

34

mycelium continued to grow in the cortical and pith regions of stem and invaded

the new developing leaf, the high moisture in the leaf appears to favour the

mycelial growth of the pathogen.

Mishra et al. (1995) has studied on disease development and physiological

changes in aubergine resulting from fungal infection, Fiisarium oxysporum

significantly reduced different plant growth parameters. The minimum

concentration of a fungal suspension harmful to aubergine cv. pusa purple long

was a 40% dilution/plant.

Kapoor (1988) has reported the nature of wilt syndrome in different

agroclimatic regions (Delhi, Maharashtra, and Tamil Nadu) of the country during

1981-83. Incidence of wilt varied from 3-100 per cent. Among 8 commercial

cultivars studied, none was found free from the disease. Collectively, the incidence

of the disease was more in Delhi and Maharashtra (>18 per cent mortality) than in

Tamil Nadu (<8 per cent mortality). Factors such as soil, root knot nematodes and

tomato monoculture aggravated the disease. Pathogens involved in tomato wilt

syndrome ate Fusarium oxysporum, F. solani, F. semitectum, F. moniliformae

(New record), F. chlamydosporum (New record), Rhizoctonia solani, R. bataticola

and Sclerotium rolfsii. F. oxysporum predominated the syndrome in Delhi and

Tamil Nadu. F. solani in Maharashtra as regarded as principal pathogens. The

dominance of these pathogens was correlated with their aggressiveness.

Association of Rhizoctonia with wilt syndrome is more common in Maharashtra

and Tamil Nadu than in Delhi. In pathogenecity tests, F. oxysporum, F. solani,

F. semitectum, F. moniliformae, F. chlamydosporum and R. bataticola were most

aggressive and caused 75-100 per cent mortality of the inoculated plants within

three weeks. Whereas, isolates ofR. solani caused 60-80 per cent mortality.

Mohit Singh and Shukla (1986) have reported the brinjal leaf spots in two

phases. Atmospheric temperature, relative humidity and age of the plant play an

35

important role in disease development. The disease appeared in the first fortnight

of July and gradually increased upto November. There was a decline in disease

severity with the lowering temperature and RH upto December. Maximum disease

intensity (30-72 and 30-81 %) was recorded from the second fortnight of October

to the second fortnight of November. When temperature varies between

28.7-32.2°C and minimum of 15.5- 20.3°C. RH ranged between 62.74 maximum

and 32.46% minimum. The minimum disease intensity (9.37 and 10.37 %) was

observed in July, when both the atmospheric temperature and RH were high in

December.

Dingar and Mohit Singh (1985) reported the important factors favourable in

development of leaf spot disease of brinjal. The temperatures and relative

humidity ranging between 24 to 26°C and 47.3 to 51.2 per cent follows the leaf

spot diseases. Scanty rains and long dry weather is adverse effect on disease

development than intermittent rainfall. Optimum favourable period when the

disease incidence was at the highest was from third week of October to the end of

second week of November.

Sher Singh et al. (1983) reported twenty-seven diseased tomato fruits in

three sets were kept at different temperatures maintained in different incubator.

The pathogen was identified as Cladosporium oxysporum caused by post harvest

decay of ripe tomato fruits. At lower temperature (10-20°C) the disease intensity

was very low but increased rapidly at 25°C and was maximum at 30°C. There was

a fall in disease intensity at 35°C though it was more than that of lower

temperatures. All the inoculated fruits incubated between 50 to 100 per cent

relative humidity became infected with the maximum at 95 per cent RH.

Datar (1983) reported the fruits inoculated with Fusarium moniliformae

showed reddish brown discolouration on calyx and stem end of the fruits. All the

36

fruits dropped on the third day after inoculation. Fruits inoculated with Phomopsis

vexans exhibited typical symptoms of Phomopsis rot. There was brown to black

discolouration from stalk end and the tissues were soft. Fruits which were

inoculated with the ftmgi. The pathogen has synergistic effect in causing fruit

rotting in brinjal. Srinivasa Rao and Thirupathaiah (1981) reported leaves of

brinjal during October and November were seen to develop large dark brown leaf

spots that irregularly spread over this entire area of leaf. The hyphae were

branched and septate.

Avdesh Narain and Rout (1981) reported during February 1979 a severe rot

of tomato {Lycopersicon esculentum L.) fruits (CV pusa red) was observed in

Orissa. The casual organism was identified as Cladosporium tenuissimum. The

disease appeared only on green fruits. Initially a light brown pin points lesion

developed at the detached blossom end of the fruit. It gradually, increased in size

and the colour of lesion changed to blackish brown. As the infection progressed,

almost three fourth the fruit surface showed dry shrunken black epidermis. Such

foliage never reached maturity. The meteorological data indicated that

80% humidity and 25°C temperature prevailing during the time of disease

incidence favoured a high degree of infection on a large number of premature

fruits.

Joshi and Raizada (1980) reported tomato crop was found to be infected

with various pathogenic fungi including Alternaria alternata, A. solani,

Cladosporium fulvum, Colletotrichum capsici, Curvularia lunata, Fusarium

oxysporum and Phoma sp. which mainly infested the leaves and fruits. Among

these, A. solani caused a severe blight of plant parts some times eliminating a

major portion of the crop. While, F. oxysporum was reported to cause serious wilt

of the plants resulting in their premature death. Monilia spp. caused the fruit rot

and Drechslera sp. the leaf spot diseases.

37

Sharma et al. (1978) and Sharma and Sohi (1975) have reported the

incidence of buckeye rot of tomato {Phytophthora parasitica) varied directly with

the amount of rainfall and temperature. A prediction equation was developed,

based on weekly temperature and cumulative rainfall, for short term forecasting of

the disease. The disease is not expected to occur at temperatures at or below

20°C, though at temperatures of 22.5°C or above even a slight rainfall of 10 mm

would cause the disease, which is expected to appear after 4 days.

Mehta et al. (1975) studied pathogenesis in case o^ A. tenuis and A. solani

on tomato fruits. Among various methods of inoculations tried, Granger and

Home's method was found to be most successfiil. Effect of different factors

i.e., temperature, relative humidity, age of the pathogen and age of the fruits have

been studied in detail; 28°C. 100 per cent R.H. and 4 and 8 days old inocula were

found to be most effective in the production of disease. Semi ripe fruits were

found to be more susceptible than ripe fruits.

2.3. Transmission

Seeds are the main carriers of the pathogen from one place to another. The

pathogen may be present in the seeds as externally or internally. Naturally infected

seeds are the source for carrying the pathogen from one place to another place.

The chilli, brinjal, tomato and okra. have fungal diseases known to be seed

transmitted. Many researchers have worked on the transmission of vegetable

seeds.

Usha Bhale et al. (2000) studied seed to seedling transmission of

Colletotrichum dematium and Alternaria alternata in chilli. They observed the

virulence of both the fungi tested by seed and soil infestation method. Artificially

injured and water soaked seeds had greater seed infection, 69 and 63 per cent as

compared to 49 and 45 per cent in uninjured seeds with C. dematium and

38

A. alternata respectively. Seedling symptom test was better in the detection of

pathogen in seedlings.

Sunitha Agrawal and Tribhawan Singh (2000) reported the seed-borne

infection of Macrophomina phaseolina in okra resulted, in seed-rot, symptomatic

seedlings and their mortality in water agar test. The pre-emergence loss was

significant in symptomatic (37.33, 48%) weakly and (42.66, 48%) heavily

discoloured seeds than in asymptomatic (1.33, 2%, 33%) seeds. Seed germination

was 84.90, 66% in asymptomatic, 24, 42.66% in weakly discoloured and 21,33,

24% in heavily discoloured seeds. The present study, pycnidia formation was not

observed on rotted seeds and seedlings in water agar test. The seeds with deep-

seated inoculum rotted prior to germination showed post-emergence mortality.

Cleaned preparation of infected seedlings showed inter and intracellular mycelium

and microsclerotia of M phaseolina in cortical vascular tissues of radicle.

Kulbe and Sati (1987) reported Alternaria raphani seed transmitting nature

in tomato. The seeds associated with A. raphani showed black cottony mycelium

with a large number of Conidia and Chlamydospores. During seed-bed

observation, under field condition, a number of seedlings showed leaf blight,

damping-off and wilting due to infection of A. raphani, pathogenecity test under

glass house conditions was conducted by infestation of seeds with sporulating

culture of ^. raphani. The results showed reduced seed germination (55 per cent),

leaf blight and wilting and damping-off of seedlings.

Vidhyasekaran and Thiagarajan (1981) reported Fusarium oxysporum

infection reduced seed germination, growth rate and fruit yield and was frequently

isolated from chilli seeds. Seed-borne infection induced wilting in the transplanted

crop and fruit rot was common. Seeds obtained from the plants grown from

infected seeds showed the presence of F. oxysporum.

39

2.4. Location of the pathogen in the seed

Study of the locality of the pathogens in the seeds is very important. The

study helps to know the location of the pathogen in the different components of

the seeds, seed contains seed coat, cotyledons and embryonial axis. Based on its

position chemical treatments are recommended. Many researchers have worked

and the location of the pathogen in the seed components in different crops.

Sunita Agrawal and Tribhuwan Singh (2000) studied the naturally infected

seeds of okra (Abelmoschus esculentus (L.) Moench.) with Macrophomina

phaseolina causes die-back. Root and collar rot diseases, the incidence of which

in seed samples of Rajasthan varied from 0.5 to 18%. Infected seeds were

symptomatic with or without microsclerotia. In asymptomatic seeds the mycelium

was confined in the seed coat and endosperm only, whereas mycelium and

microsclerotia occurred in seed coat, endosperm and embryo of symptomatic

seeds. 10-20% inter as well as intracellular mycelium only in seed-coat, fringe

layer and endosperm of asymptomatic seeds, whereas in widely and heavily

infected seeds it was observed 20 to 60%, 70 to 100% as extra-embryonal and

20 to 30%), 50 to 70%> as intra-embryonal respectively.

Component plating method revealed that the infection of Alternaria

brassicae in the seeds of rapeseed and mustard is mainly located internally in the

seed coat and rarely in the embryo. The range of internal seed coat infection varied

between 3%) and 16%), but embryo infection was found only at 1%) in two samples

(Shrestha et al, 2000).

Basak (1998) recorded the mycoflora of chilli seeds in different seed

components. The highest percentage of recovery of Colletotrichum capsici in seed

coat, endosperm and embryo was 92.0%), 82.0%) and 80.0%) respectively.

Infection of chilli seeds with C. capsici absent in endosperm and embryo.

40

Karuna Vishunavat and Sanjay Kumar (1994) have recorded the mycoflora

of Brinjal seeds. Component plating of seeds on blotters yielded 22% and 12%

Phomopsis vexans infections on seed coats and cotyledons, respectively. Whole

amount preparation of both seed coats and embryo showed the presence of

mycelium in both seed coats and embryo.

2.5. Yield loss

Fungal diseases play role in considerable yield loss. Diseases are major

threat to vegetable crop production. Many workers have studied the yield loss of

vegetable crops from different areas.

Rang Pal Singh and Sher Singh (2001) studied early blight caused by

Alternaria solani affect the tomato crops at all the stages of growth. Severe

epidemic of this disease cause losses upto 78.51 per cent in tomato fruit yield

where as naturally infected crop reduced 46.26 per cent yield. In India, kharif

crop suffers heavy losses due to early blight.

Sastry and Singh (1973) reported the loss in tomato crop due to leaf curl

virus infection resulting upto 92.3 per cent of loss. The plants, which were infected

after 35 and 50 days following planting, produced on an average 12 and 22 fruit

and resulted in 74% and 28.9 per cent loss. Cerkauskas et al. (1999) have reported

the powdery mildew of pepper. Yield losses of 10-15% were noted in Reamington

and Vineland, in Southern Ontario, Canada.

2.6. Disease management

Disease management plays an important role in controlling the disease

development. Among these methods chemical and biological methods are widely

used. Many researchers were also worked in this field.

41

2.6.1. Physical control

Ruchi Sood and Sharma (2003) studied the management of fruit rot of

tomato caused by Alternaria spp., holding the fruits at 38°C for 72 hr. or 96 hr.

effectively or completely checked the Alternaria infection by heat treatment. In

hot water treatment at 52°C for 5 minutes showed better control of Alternaria spp.

Where as hot water with Mancozeb treatment is completely eliminated A. tomato

and reduced significantly A. alternata and A. solani.

Satvinder Kaur (2000) have studied the different fields as follows:

Dry heat : To manage plant pathogens is based on the differential tolerance of

temperature by the host and pathogen suitable technologies can be diversed based

on thermal death point of the pathogen and maximum temperature tolerated by the

host.

Solar heat : In solar heat treatment of wheat seed recommended to control loose

smut is also equivalent to warm water treatment of infected seed.

Washing : In wheat seed washed with chlorinated water to make seed free to

kamal bunt and other diseases.

Radiation : Gamma radiation and high energy electron beams are being used for

seed treatment unit of 15 ton capacity has been deployed which can eliminate

Tilletia carries in wheat seed lots. With 99 per cent efficacy at 2 kgy.

Microwaves : The phytocidal effect of the waves is due to the increase in

temperature on hitting the water molecules in the soil. It can achieve 100°C

temperature in 4 to 45 min. depending upon the dose, RMC (%), and depth of soil.

Fusarium and Rhizoctonia spp., become inactive at 50-52°C.

Ultrasonic waves : Ultrasonic technology has been used in metered fertilizers and

application of plant protective chemicals. The efficacy was depending upon

intensity of the treatment.

Forceds air circulation : The debris of contaminate can be sucked out of the seed

lot with electronic devices. The infected seed was removed by virtue of being light

42

in weight. Physical protection to reduce post harvest fruit and vegetable spoilage

by using wrap films is another promising avenue, physical methods had not been

exploited to their maximum potential in the management of plant pathogen.

Karunaratne (1999) studied the effect of hot water treatment of tomatoes,

cucumbers, chilli and carrots (50°C, 1 min.), Phaseolus vulgaris (50°C, 30 S) and

okra seeds (52°C, 30 S), at room temperature (27.13°C) was determined.

Irrespective of treatment did not develop disease symptoms after raised them in

the experimental plots.

Lurie et al. (1997) studied the effect of low temperature on tomato fruits.

The hot air was compared to hot water and their effects on reducing chilling injury

and fungal decay was investigated in a laboratory. All the heat treatments reduced

chilling injury and decay in tomatoes held for 3 weeks at 20°C and fruit rot

development by all the fungal pathogens was completely arrested when inoculated

chilli fruits were kept at 0 and 50°C (Datar, 1995).

Vakalounakis (1992) reported two tomato cultivars were grown during

1986-87 and 1988-89 crop seasons in a green house covered with a long-wave

infrared absorbing (IRA) and vinyl film. They have recorded total disease index

for all 3 diseases (early blight, caused by Alternaria solani, leaf mold caused by

Cladosporium fulvum and grey mould caused by Botrytis cinerea) on both

cultivars was much less in the IRA-Vinyl green house (40-50%) than in the

CA-vinyl green house. In the IRA-vinyl green house, the first harvest of mature

fruits from both cultivars was made C.60-70 d earlier and plant growth (height,

stem diameter inflorescence number and fruit production) was better than in the

CA-vinyl green house.

43

2.6.2. Chemical control

Fugro and Mandokhot (2002) studied the date of transplanting to control of

early blight of tomato for three successive years in a split design using four

transplanting dates as main plot treatments, viz., 5"̂ November, 20**" November, tK fVi

5 December and 20 December and two fungicides as subplot treatments,

namely, Indofil M-45 (0.25%) and Chlorothlonil (0.25%). The crop transplanted

during 45* week and sprayed with Indofil M-45 (Mancozeb) produced

significantly higher yield (31.89 t/ha.) of tomato. The incidence of blight was

significantly lower in the said treatment (35.08%) at temperature around 26°C and

relative humidity about 60-61% were most conducive factors for blight

development

Bhoraniya et al. (2002) reported the fungal diseases affecting chilli, stem

rot caused by Sclerotium rolfsii is serious in tropical and subtropical regions in

India. Com meal amended fields soil (5% w/w) was used in evaluating the

effectiveness of pesticides against sclerotial germination. The observations

recorded on per cent inhibition of sclerotial germination showed the effectiveness

of Carboxin (98.99%), followed by Tridemorph (97.89%) and Fluchloralin

(94.02%). Metalachlor was also found effective in inhibiting the sclerotial

germination (62.78%).

Sood and Sharma (2002) studied the three systematic and six

non-systematic fungicides were tested for their comparative efficacy against black

rot of tomato. The antifungal compounds were Carbcndazun, Thiabendazole,

Thioplanets methyl, Ridomil-MZ, Copper oxychloride, Mancozeb, Captan and

Bordeaux mixture (5.5:50), the systemic fungicides at 500 |ig/ml and

non-systemic at 2000 |j.g/ml concentration were used. The disease was controlled

completely with Bordeux mixture (1%). Pre-harvest application of Indofil M-45,

44

reduced the black rot significantly while Ridomil-MZ, Blitox-50 and Captan also

controlled more than 70 per cent disease.

Anitha and Tripathi (2001) have screened the different fungicides against

Rhizoctonia solani and Pythium aphanidermatum, causing seedling mortality of

okra, in the laboratory as well as in the green house. Carbendazim, Thiophanate-

methyl, Carboxin, Thifluzamide and Captaf were found effective against R. solani

while Metalaxyl, Captaf, Carboxin and Iprodione against P. aphanidermatum

under laboratory conditions. In the green house studies, maximum disease control

(62.79%) was achieved with Carbendazim and Carboxin. When fungicides were

tested against fiingal and bacterial antagonists in the laboratory. Carboxin and

Metalaxyl did not inhibit the fungal antagonist, Trichoderma viride, while little

inhibition of Gliocladium virens was noticed at 0.1 per cent. However,

Carbendzim and Thiophanatemethyl inhibited both the fungal antagonists. The

fungicides did not inhibit the growth of bacterial antagonists.

Vijayakumar (2001) studied influence of agro-ecological conditions in

bhindi seeds. The results revealed that among the place of storage, seeds stored at

Coimbatore, Yercaud, Kodaikanal and Paiyur maintained higher viability and

vigour for 24 months. The seeds treated with Thiram at 2g kg"' of seed stored in

polyethylene bag remained viable for longer period as compared to seeds stored in

cloth bag in all the places of storage. The seeds remain viable for 21 and

15 months when stored in polythene and cloth bags respectively irrespective of

treatments, locations and periods of storage.

Chander Mohan and Thind (2001) have studied fungicides evaluation trials

were conducted on tomato. The treatments werp given as preventive and curative

applications of fungicides at 7 and 10 days intervals for contact and systemic

fungicides. The treatments were replicated thrice with each replicate having

40 plants in 12-m row. Among various treatments given prophylactically,

45

Ridomil- MZ, above Ridomil-MZ followed by Indofil M-45 and Indofil M-45

followed by Ridomil-MZ were found to be most effective, highly effective

treatments were Indofil M-45 (7 day interval) Karach and Acrobat MZ, Blitox

proved relatively less effective.

Hegde and Kulkami (2001) have studied percent mortality of chilli

seedlings by different treatments. Least percent mortality was observed in Captan

treated seeds (10.13) compared with Pseudomonas florescence (11.12) and Thiram

(12.34). In control maximum percentage mortality (63.25) was recorded.

Suryawanshi and Deokar (2001) have studied the effect of different

fungicide agianst pathogens of poisoned food technique by fruit rot in chilli. In

vitro evaluation of fungicides, Carbendazim (0.10%) and Copper oxychloride

(0.25%) completely inhibited growth and sporulation of Fusarium oxysporum

followed by Thiophenate methyl (0.05%). In case of F. moniliforme, Carbendazim

(0.1%) and Ziram (0.20%) had completely checked the growth and sporulation,

whereas Triadimetton (0.05%) was found in ineffective.

Cercospora leaf spot of okra can control by Cantaf, Vitavax and Bavistin.

The disease resulted in severe defoliation of affected leaves and only 4 to

12 per cent leaves were found intact in lO"" day of final spraying of the fungicides.

Vitavax, Cantaf of and Bavistin were found most effective in retaining highest

number of green leaves compared to other fungicides and unsprayed check plots,

(Dharam Singh etal. 2001).

Mukherjee and Tripathi (2000) have reported, among 8 fungicides

evaluated. Antracol was found most effective against the pathogens and

non inhibitory to the antagonist, even at higher concentration. Seed treatment with

the spore mass of the antagonist and fungicides. Opus, Contaf and Antracol (0.1%)

increased per cent seed germination, shoot length, vigour of the plants and number

46

of leaves per plant under glass house conditions in French bean. The disease

incidence was reduced significantly.

Iboton Singh et al. (2000) reported effect of fungicides over growth and

sporulation oiFiisarium solani. After 50% reduction in concentration of each test

fungicide, Baynate, Carbendazim and Indofil M-45 could still easily inhibit the

growth of the fiingus. However, Blitox-50 and Captan failed to inhibit the growth

as the fungus growth covered 3.13 and 2.0 cm diameter of the petridish only when

the fungus could cover 9.0 cm diameter.

Sidanath Singh et al. (2000) have reported Colletotrichum capsici by

die-back diseases of chilli is causing heavy loss to the crop and limiting the

production of chilli, out of 12 fungicides evaluated against C. capsici, Bavistin at

100 ppm, Emisan-6, Thiram, Blue copper-50 at 800 ppm and Indofil M-45 and

Blitox-50 at 1000 ppm completely inhibited the growth and spore germination.

Singh and Agrawal (1999) studied the seven treatments viz., Mancozeb,

Carbendazim, Mancozeb and Carbendazim, Thiophanate methyl, Mancozeb and

Thiophanate methyl, Copper oxychloride and unsprayed were effective against

Phomopsis fruit rot of brinjal. It is concluded that two spray of Carbendazim

(0.1%) one at the first symptoms appearances and second 15 days after first spray

is the most effective chemical control in RBD method.

Sidnath Singh et al. (1999) revealed that among the fungicides tested

maximum seed germination (90%) when seeds were treated with Bavistin (0.1%)

with Thiram (0.2%) which resulted in 88.0% germination followed by Captan

(0.2%), 84.0 germination per cent, Emisan-6 (0.2%) exhibited 81.0%) germination.

Seeds treated with Vitavax (0.25%)) and Difolaton (0.25%)) exhibited poor

germination 67.0 and 63.0%). Maximum protection to seeds was observed in case

of Bavistin which suppressed upto 91.9% of Colletotrichum capsici being at par

47

with Thiram (89.1%) followed by Captan (83.8%), Emisan-6 (81.0%), Vitavax

(51.4%) and Difolatan (37.8%).

Satpathy and Rai (1999) studied the effect of chemicals, botanicals and

biopesticides were evaluated in different combinations during vegetative and

reproductive stages of okra in icharif 1996 and 1997. Among the treatments in

vegetative phase, Monocrotophos, Endosulfan, Monocrotaphos + Cypermethrin

restricted jussid population most efficiently. Monocrotophos + Cypermethrin

combination also reduced the shoot borer damage.

Usha Bhale et al. (1999) have studied the effect of Streptopenicillin on the

chilli seed mycoflora. The tested of Streptopenicillin shows maximum inhibition

of agar plate method. The association of Alternaria alternate was found maximum

(31%) in untreated seeds as observed in standard blotter method.

Singh et al. (1998) and Ragupathy et al. (1998) have studied the powdery

mildew of okra can be controlled by Sulfar spray treatment (1:20.44) followed by

Tridemorph (1:13.0). Three sprays of 0.05% Tridemorph or 0.2% Sulfur after the

appearance of disease symptoms can be recommended and the four sprays of

Penconazok (0.05%) and Cyptoconazole (0.02% and 0.03%)) at 15 days interval

were the most effective in reducing Erysiphe dehoracearum.

Al Kassim (1996) has recorded the Carbendazim, Benomyl and Copper

oxychloride + Zinc, Mancozeb and Metalaxyl were used as seed treatments of

okra, capsicum, radish, and soybean in Saudi Arabia. The number of fungal

species was greatly reduced treated with 0.2% concentration. Benomyl was the

most efficient seed treatment followed by Copper oxychloride + Zinc and

Mancozeb.

48

Mandal and Sinha (1992) reported the effectiveness of mostly non-toxic

chemicals in wet seed treatment used at dilute concentrations, in controlling

Fusarium wilt of tomato. The Cupric chloride, Ferric chloride. Zinc chloride,

Manganese, Sulphate, Mercuric sulphate, L. cystrime, lAA and Dl-methionine

showed very strong protective effect. These reduced leaf symptoms by 52 to 71%,

prevented mortality completely and also limited vascular colonization by the

pathogen-most of the test compounds showed little or no in vitro fungitoxicity of

their effective concentration and stranger protection was often achieved at lower

than higher concentration.

Mridha and Chowdhury (1990) have studied chilli seeds with high natural

infection by Altemaria tenuis {A. alternata), Colletotrichum capsici and Fusarium

moniliforme (Gibberella fujikuroi) treated with Benlate, Manzate and

Vitavax-200. All treatments at 0.45 and 0.6% of seeds completely controlled

A. alternata, G. fujikuroi and C. capsici was reduced by all treatments.

Dhyani et al. (1990) reported Capsicum seeds were dressed with

7 fiingicides. Bavistin (Carbendazim), Brassicol (Quintozene), Captafol, Dithane

M-45 (Mancozeb), Thiram, Topsin (Thiophanate-methyl) and Vitavax (Carboxin)

at 0.3%. Thiram gave the best control of seed borne fungi followed by Captafol

and Mancozeb. The remaining fungicides were ineffective against P. destructiva.

Thind and Jhooty (1987) have reported 12 different fungicides, Difolatan

(0.2 per cent) proved most effective in controlling both Anthracnose and

Altemaria fruit rot of chilli. Even lower dose, that is, 0.1 per cent of Difolatan

gave control oi Altemaria rot although it was not effective against anthracnose to

appreciable extent.

Dharam Vir and Indra Hooda (1987) have evaluated different chemicals in

controlling damping-off of tomato and chilli caused by Fusarium solani and

49

Pythium aphanidermatum. As seed treatment Copper oxychloride best controlling

damping-off by F. solani and for the Pythium aphanidermatum MEMC was the

best fungicide. However, for controlling damping-off caused by both the fungi

MEMC and Captan were very promising on tomato and Captafol on chilli.

Kaur and Jhooty (1987) have studied the effect of foliar spray on one

month old seedlings of egg plant cv. pusa purple lang. raised in the nursery treated

seeds (Thiram at 3 g/kg seed) with were transplanted in the first week of July in a

randomized block design in 5x4 cm beds with these replications in each treatment

subsequently 3 sprays were repeated at 10 days interval. Among all the fungicides

Dithane Z-78 was the best. Bordeaux mixture, Blitox, Dithane M-45 and

Cuman-Ri were the next in order as the per cent infected fruits with these were

15.25, 18.58, 21.25, and 23.21 respectively.

Deena and Basuchaudhary (1984) have reported in chilli seeds. The

Carbendazim, Carboxin, Mancozeb, P.M.A., Quintozene and Zineb fungicides

reduce colonization by fiingi. Quitozene and Mancozeb eliminated most of

saprophytic fungi. Dreschlera tetramera by Quintozene and PMA; Colletotrichum

capsici and Colletotrichum sp. by Zineb. Although it lowers the germination

slightly still it can be recommended.

Verma et al. (1994) has studied fruit rot caused by Phytophthora nicotianae

var. parasitica and P. infestans on 4 tomato cultivars. Dithane M-45 and Ridomil

MZ-72. In the case of fungicides, significant differences were recorded for number

and weight of quality fruits and number of diseased fruits. Rama, a recommended

gave the highest yield of quality fruits with Ridomil MZ-72 and the best seed yield

with Dithane M-45. Vimala et al. (1993) has studied the brinjal seeds treated with

fungicides Carbendazim, Captan and TMTD (Thiram). All treatments increased

seed germination with Carbendazim giving maximum germination

(92% compared with 76.5% in control) and Smith et al. (1999) studied the

50

problems of chilli peppers and bell peppers by powdery mildew {Oidiopsis

taurica, Leveillula taurica). Research has shown that several fungicides can

control this disease. Sulfur is most effective as a preventive fungicide.

Sher Singh et al. (1983) have studied the post harvest decay of ripe tomato

fruits by Cladosporium oxysporum. In pre-infection, Miltox and Difolatan proved

significantly superior and protected 75 per cent of the fruits from rotting, followed

by Benlate, Blitox-50, Captan, Brestan, Udankor and Actidiane, each of which

protected 62.5 per cent of infected fruits. The efficacy of Triazine, Trametan and

Topsin was not satisfactory. In post infection treatment, the performance of Miltox

was statistically significant as it protected more than 74 per cent of the infected

fruits. Next, Difolatan followed by Captan, Benlate and Blitox-50.

Raja Gopal and Vidhyasekaran (1983) reported the Mancozeb and Caplafol

were effectively controlled Alternaria and Septoria leaf spot diseases of tomato.

These treatments reduced the defoliation and increased the fruit production.

Weight of the fruits from the unsprayed plots was less compared to those from the

fungicides treated plots.

Dharm Singh and Chakrabarti (1982) reported Phomopsis fruit rot caused

by Phomopsis vexans (Sacc. and Syd.) is serious disease of brinjal seed crop. The

treatment with the chemicals like Captan, Difolatan, Benlate, Thiram, Calixin,

Bavistin and hot water did not have significant effect on the emergence and stand

of the brinjal seedlings in nursery beds. In the spray treatments the minimum

disease incidence and maximum seed yield were obtained from Difolatan and

Captan treatments. Calixin was found phytotoxic to the crop even at lowest

recommended concentration.

Dwivedi and Pathak (1981) reported the effect of some chemicals to

Fusarium oxysporum f sp. lycopersici in tomato. To check the growth of

51

Fusarium oxysporum f. sp. lycopersici with 0.1 per cent Bavistin and Difolatan. In

PCNB treatment better growth than control was recorded. Carbofuran, Temic,

Phorate, BHC, Lindane and Nuvacron were not very much effective.

Vidhyasekaran and Thiagarajan (1981) have studied the chilli seeds treated

with five different fungicides. Among the fungicide Vitavax were highly effective

in eradication of the pathogen from seed and increasing seed germination, Thiram

and Benlate-T were also effective in the control of seed-borne infection by the

pathogen, Baytan was less effective in the control of the Fusarium oxysporum in

chilli seeds.

2.6.3. Biological control

Banker and Kusam Mathur (2001) have studied integration of seed and soil

application of individual biocontrol agents resulted in higher germination and

reduced mortality of disease. Combination of two biocontrol agents of

Trichoderma harzianum and Trichoderma aureoviride was better than the

individual ones. Application of mixture of T. harzianum and T. aureoviride as

seed and soil treatment was the most promising in increasing the germination and

suppression of chilli root-rot pathogen and the disease.

Manoranjitham and Prakasam (2000) and Manoranjitham et al. (2001) has

reported the Damping-off of tomato by Pythium aphanidermatum reduced by the

application of talc based formulation of Trichoderma viride and reducing pre and

post-emergence damping-off, these antagonists increased the root length, shoot

length and biomass production of tomato seedlings. Ramamoorthy and

Samiyappan (2001) have studied the efficacy of various P. fluorescence isolates

was tested for the management of fruit rot of chilli by Colletotrichum capsici.

P. fluorescence isolate Pfl effectively inhibited the mycelial growth of the

pathogen under in vitro conditions and decreased the fruit rot incidence under

green house conditions.

52

Sood (2000) has reported that bacterial wilt caused by Ralstonia

solanacearum is an endemic disease of tomato in the mid-hill areas of Himachal

Pradesh causing 80-90% loss in yield. Attempts have been made to manage this

intricate disease through host resistance. The antagonistic rhizobacterial isolated

Pseudomonas fluorescence and Bacillus sp. gave better control by delaying the

initial appearance of wilt by 30 days and reducing the terminal wilt incidence to

44.4% and 33.3% respectively. In control treatment wilt started appearing after

14 days and complete wilting occurred within six days. The avirulent strain A| of

R. solanacearum was found effective in delaying the incubation period upto

20 days but the terminal wilt was not reduced.

Mathivanan et al. (2000) and Manoranjitham and Prakasam (2000) reported

seed treatment with talc-based formulations of Trichoderma viride and

Pseudomonas fluorescence effectively reduced the pre and post emergence

damping-off of chillies by Pythium aphanidermatum. T. viride at 4 g/kg +

P. fluorescence at 5 g/kg recorded 31.65, 66.66 and 37.58% increase in shoot

length, root length and dry matter production over the control respectively. At

20 days after sowing both fungicide (Captan 4 g/kg) as well as bio-control agents

(T. viride 4 g/kg +P. fluorescence 5 g/kg) treatments recorded P. aphanidermatum

population.

De Cal et al. (1999) have studied the effects of timing and method of

application of Penicillium oxalicum on the control of Fusarium wilt of tomato.

Disease suppression was maintained for 60-100 days after inoculation with the

pathogen in the glass house. No disease reduction was observed in tomato plants

where P. oxalicum was applied to seeds treatment with P. oxalicum did not affect

the population of F. oxysporum f sp. lycopersici in the rhizosphere.

Padmodaya and Reddy (1998) studied ten isolates of Trichoderma spp. and

Bacillus subtilis against seedling disease (damping-off) and wilt of tomato. In seed

53

treatment among the antagonists healthy seedUngs stand range from 45 to 65%

while control showed 27%. T. viride recorded the highest seedling stand (65%)

followed by Pseudomonas sp. (63%o) and Trichoderma sp. {62%). Uninoculated

healthy control recorded 82%) healthy seedlings.

Larkin and Fravel (1998) have reported the wilt of tomato caused by

Fusarium oxysporum. The seedlings were treated with the potential bio-control

agents in the green house and transplanted into pathogen infested field soil in pots.

Organisms tested included non-pathogenic strains of Fusarium spp., Trichoderma

spp., Gliocladicum virens, Pseudomonas fluorescence, Burkholderia cepacia and

others. Fusarium wilt suppressive soil were the most effective antagonists,

providing significant and consistent disease control (50 and 80% reduction of

disease incidence) in several repeated tests.

Edalthol et al. (1996) reported that the tomato seedlings grown in sterile,

phosphorous deficient soil and inoculated with 4 species {Glomus aggregatum,

G. fasiculatum, G. geosporum and G. sinuosum) of vesicular arbuscular

mycorrhizal (VAM) fungi in 15 combinations. Mycorrhizal plants exhibited a

significantly higher shoot length and biomass, than non-mycorrhizal plants

(P>0.05). VAM also increased host tissue N and P concentration. Among the

VAM combination, inocula containing all 4 cndophytes proved better than others.

Mycorrhizal dependency, percentage increase of biomass compared with controls.

Theradi Mani and Marimuthu (1994) have studied the effect of decomposed

coconut, coir pith, fungicides, and bio-control agents on damping-off chillies and

dry root rot of blackgram. Among this, decomposed coir pith was comparable with

Trichoderma hamatum and T. viride-2 which recorded 16.3 and 11.5 per cent post

emergence damping-off in chillies, whereas, decomposed coir pith above and in

combination with T. harzianum-2 were increased the per cent survival of plants.

54

El-Abyad et al. (1993) reported three Streptomyces spp. {S. pulcher,

S. canescens and S. citreofluorescens) were used to evaluate the potential of

microbial antagonism for the control of some tomato diseases including bacterial

{Pseudomonas solanacearum), Fusarium (F. oxysporum f sp. lycopersici) and

Verticillium {V. albo-atrum) wilts ; early blight {Alternaria solani) and bacterial

canker (Clavibacter michiganensis sub sp. michiganensis). In vitro studies showed

80% concentration of the culture S. pulcher or iS. canescens significantly inhibited

spore germination, mycelial growth and sporulation of F. oxysporum f sp.

lycopersici, Verticillium albo-atrum and A. solani. The results also revealed that

seed coating with antagonistic Streptomyces spp. significantly improved tomato

growth.

Alex Sivan and lian Chet (1993) have reported Fusarium crown and root rot

of tomato by Fusarium oxysporum f sp. radicis-lycopersici. The combination of

T. harzianum with methyl bromide (300 kg ha'') at soil solarization, reduced the

final colonization level of Fusarium spp. on the crown surface by 76 or 94%

respectively. This study reveals that combination of T. harzianum with a sub-lethal

dose of methyl bromide or soil solarization is effective in controlling of Fusarium

oxysporum f sp. radicis-lycopersici in tomato.

Sivan (1987) have studied biological control experiments were carried out

during growing seasons in tomato fields naturally infested with Fusarium

oxysporum f sp. radicis lycopersici. Trichoderma harzianum was applied as a

seed coating or as a wheat bran/peat (1:1 V/V) preparation introduced into the

tomato rooting mixture. Trichoderma treated transplants were better protected

(P = 0.05) against Fusarium crown rot than untreated controls when planted in

methyl bromide-fumigated or non-fumigated infested fields. The total yield of

tomatoes in the T. harzianum treated plots with increased as much as 26.2% over

the controls. When T. harzianum was applied to the root zone of tomato

55

transplants. When tomato seeds previously treated with conidia of T. harzianum

were sown in a naturally infested field, the antagonist was detected on root

segments from plants sampled 20 week after planting.

2.6.4. Control through plant extracts

Pumima Daragan and Saxena (2002) reported the effect of Withania

somnifera on fruit rot of tomato caused by Aspergillus niger in presence of

Prosophis basckii. The plant extract was obtained by girdling 10 g of freshly

collected leaves with 100 ml of distilled water to make 1 and 0.1 per cent

concentration. Both the germination of spores and growth of the fungus was

adversely affected by the leaf extract of W. somnifera. The standard (100%)

concentration was most effective and the fruit rot development most adversely

affected in the treatment with 100% concentration.

Kanwar and Walia (2002) have reported efficacy of chenopodium and

neem as nursery soil amendment in the management of root-knot nematode in

tomato. Uses neem and shoots of Chenopodium sp. The number of galls was

reduced more in seedlings raised in amended than chemical treated or unamended

soil. However, the effect of both Chenopodium species was similar. C. album,

C. murale and neem leaves can be used judiciously and effectively against root-

knot nematode as nursery soil treatment.

Asha and Kannabiran (2001) have reported effect of Datura metel leaf

extract on the biochemical changes in the leaves of chilli seedlings infected with

Colletotrichum capsici one week-old healthy seedlings were inoculated with

2-3 X lOVml spore suspension of C. capsici. After 24 hours of inoculafion, the

seedlings were sprayed with 10% aqueous leaf extracts of Datura metel.

Uninoculated plants and infected plants were also simultaneously maintained

samples for the biochemical assays were collected at 15,25,35 and 45 DAS. In the

56

control seedlings, the activities of PMG and CMC enzymes were absent.

A considerable reduction in the activity of PMG and CMC was observed in the

treatment seedlings on all days of sampling. The inhibition of enzymes of

C. capsici might be due to the phenolic compounds or some other compounds.

The above results show that D. metel leaf extracts as sprayed at 8 DAS could

protect chilli seedlings against C. capsici upto 35 DAS and a further spray is used

for further protection.

Gomathi et al. (2001) reported the conidial germination of Colletotrichiim

capsici and C. gloeosporiodes was totally inhibited by heat-treated aqueous

extracts of Solarium torvum, Datura metel and Prosophis juliflora. Higher percent

inhibition of radial growth of C. capsici and C. gloeosporioides was brought about

by ethanol extract of D. metel (84.52% and 87.5%) followed by heat treated

aqueous extract of 5. torvum (82% and 79.43%).

Chitra and Kannabiran (2001) have reported the effect of fruit ethanol

extract and flower hot water extract of Datura innoxia on the physical and some

metabolic activities of the pathogen Colletotrichum capsici, the result shows the

reduction in the DNA content of the fungus, when it was inhibited by the extracts

of Z). innoxia (Fruit ethanol extract, Flower hot water extract) compared to control.

But the RNA (Fruit Ethanol extract, Flower hot water extract), and protein (Fruit

ethanol extract, Flower hot water extract) contents of C. capsici were found to

increase compared to control.

Babu et al. (2001) reported the Vitex negundu significantly reduced the

mycelial growth of Alternaria solani. Fresh leaves of 25 plants weed extract and

potato dextrose agar medium were mixed at required quantities to get 10 per cent

concentration of the leaf extract. Leaf extracts of all the plant species tested except

The spore germination was inhibited to varying degrees by all the leaf extracts.

10% extracts of Polyalthia longifolia, Azadirachta indica and Ocimum sanctum

57

were the most effective in inhibiting the mycelial growth upto 38.9, 37.7 and

28.5 per cent respectively. Pun et al. (2000) reported the neem oil and neem seed

kernel extract reduced the virus infection by 88.3 and 86.7% respectively. In

general, the neem products were found to be more effective than the virus

inhibitory chemicals in reducing per cent infection of okra.

Gomathi and Kannabiran (2000) have reported aqueous leaf extracts of

23 wild plants were screened against the anthracnose fungi, Colletotrichum capsici

and Gloeosporium piperatum infecting chilli. The leaf extracts oi Solarium torvum,

Datura metel and Prosopis juliflora were found to effectively inhibit the conidial

germination and mycelial growth of these fungi.

Padmodaya and Reddy (1999) have reported six organic amendments are,

neem cake, pongamia cake, and pongamia fresh and dry leaves. Eucalyptus dry

leaves and farmyard manure (FYM) were studied for their effect against seedling

disease in tomato by Fusarium oxysporum f sp. lycopersici. All the concentration

of amendments increased, healthy seedling stand also increased. In general,

two-week incubation periods with 60% healthy seedlings were found superior to

four-week incubation period (59%). FYM was found significantly superior to all

others with 66% mean healthy seedlings followed by neem cake (61.1%) and

pongamia fresh leaves (61%), FYM (2%)) was significantly superior to all other

amendments. Two weeks and four weeks with 71 and 71% healthy seedlings

respectively followed by neem cake (0.15%) with 70% at two week incubation

period and at 0.1% with 67% healthy seedlings at 4 week incubation period.

Rashmi and Yadav (1999) reported four plant extracts {Oscimum basilicum,

Moringa pterigosperma, M. olieifera, Achyranthes aspera and Allium sativum)

were assayed for fungitoxicity against Alternaria alternata, causal agent of leaf

spot and blight disease in brinjal, in vitro the radial growth and biomass of the

fungus. Bulb extract of Allium sativum and leaf extract of Ocimum basilicum at

58

2.0% were the most effective plant products in suppressing radial growth and

biomass production. Leaf extract of Achyranthus aspera and Moringa

pterigosperma were almost ineffective.

Harbant Singh et al. (1999) has studied the use of crude plant extracts as an

alternative to commercial fungicides in the control of Capsicum anthracnose. The

efficacy of neem {Azadirachta indica), garlic {Allium sativum) and Tagak-tagak

{Rhinocanthus nasuata) at 5000 ppm on Capsicum annum was comparable with

the fungicide Carbendazim (Bavistin) at 100 ppm. Garlic extract performed well

under room humidity, while Tagak tagak showed good control of chilli

anthracnose under high moisture conditions. Neem extract minimized the 'ripe

chilli fruit rot'.

Kuruchave and Padmavati (1998) have reported the bulbs of Allium

sativum, leaf extracts of Lawsonia inermis, Eucalyptus globulus and Azadirachta

indica, A. juss and oil cake extract of Sesamum indicum against damping-off of

chillies. Among the plant products tested, A. sativum bulbs was found to be the

best followed by L. inermis treatment. Gingelly oil cake treatment was least

effective.

Khare and Atri (1997) reported the fifteen homeopathic drugs were

screened against Colletotrichum capsici, causal agent of the chilli fruit rot, under

In vitro and In vivo conditions. Calcarea carbonica-200, Calendula-30,

Ipecacuanha-6 and PulsatiIla-200 prevented fruit rot and Arnica-1000,

Belladonna-6, Calcarea carbonica-30, Calendula-30, Carbo vegetabilis-6,

Mercurius solubilis-1000 and Nux-Vomica-200 acted as curatives.

Singh et al. (1997) reported plant extracts of Catharanthus roseiis,

Azadirachta indica, Pongamia pinnata, Tagetes erecta and onion bulb extracts and

garlic were evaluated at 1,2,3 and 4% concentrations for radial growth and spore

59

germination of Colletotrichum capsici, incitant of die-back of chilli. Extract of

garlic bulb at 3% concentration completely inhibited the growth and spore

germination of C. capsici whereas, 4% extracts of onion bulbs. A. indica leaf,

P. glabra leaf and T. erecta leaf gave complete inhibition of fungal mycelial

growth and spore germination.

Mohanty et al. (1995) reported the allelopathic control of Phomopsis

vexans by blight and fruit rot brinjal. Aqueous leaf extracts of 5 plants was

investigated. Fungal growth was inhibited to a maximum by leaf extracts of

Allemanda cathertica (93.75%) followed by Aegle marmelos (85.38%), leaf

extracts of Catharanthns roseus, Polyalthia longifolia and Azadirachta indica

were equally effective, causing 52.23% growth inhibition.

Dubey and Dwivedi (1991) have studied the Acacia arabica, Allium cepa

and Allium sativum shows fungitoxic properties, against vegetative growth and

sclerotial viability of Macrophomina phaseolina. Harbant Singh et al. (1999)

have reported, aphids are key vectors in transmission of chilli viruses by cucumber

mosaic, tobacco mosaic virus, chilli veinal mottle virus, tomato spotted wilt virus

and alfa- alfa mosaic virus in the tropics and subtropics. The efficacy of neem

{Azadirachta indica), garlic {Allium sativum) and tagak-tagak {Rhinocanthas

nausta), were compared with malathion on chillies, against aphids at different time

intervals. The effect of Malathion was the best four days after spraying, when

almost no aphids were recorded on the plants. After four weeks, the population of

aphids increased 400-fold (P<0.001). Neem extract at 5000 PPM generally

recorded low aphid populations when compared with unsprayed control Malathion

and other plant extracts, especially at 8 and 12 days after spraying. Neem extract

also when compared with other treatments.

60

2.6.5. Cultural practices

Suman Kumar and Sugha (2000) have studied the role of cultural practices

like spacing, staking, defoliation and inter cropping was evaluated on the

development of disease.

Effect of spacing : Progressive increase in row spacing correspondingly decreased

the severity of septoria leaf spot of tomato. Row spacing of 45 and 60 cm did not

offer significantly in its effect on the development of disease and caused 57.6 and

57.8% disease respectively. The disease developed slowly in widely spaced

tomato (90 x 50 cm) and reached to the maximum of 28.2%.

Staking and defoliation : Tomato plants which were staked and lower leaves

defoliated, developed less disease compared with staked but un-defoliated plants.

Similarly, defoliated but unstaked tomato also showed less development of disease

than unstaked and undefoliated ones.

Inter-cropping : Inter cropping with maize, whether single or double row,

developed less disease than the other crops used as inter crop. Tomato cropped

alternately with single row of bean toria and maize developed more disease in

comparison to two rows of these crops. Two rows of maize provided excellent

barrier and significantly reduced the disease progress.

Munshi and Sokhi (2000) reported the environmental and public health

problems associated with fungicides have forced us to disease control strategics.

Disease management should be based on selection and use of appropriate

techniques suppresses diseases to tolerable level. The use of resistant cultivars

against several vegetable diseases has been recommended. The development

minimize fungicidal sprays. Crop rotation with suitable substitute plant is widely

used cultural practice to suppress some diseases. After sowing, mode, and

frequency of irrigation, soil amendments, plant population etc., can help in

maintaining good plant health. Uses of cultural practices with bio-control offer

eco-friendly disease management.