Chapter II

REVIEW OF LITERATURE

Till date, the use of synthetic pesticides remains one of the best known

and most extensively used pest management measures. Nevertheless, it seems

that pesticide-related tribulations are going to outnumber the pest problems.

Since the writing of Rachel Carson’s landmark, Silent Spring in 1962, much

controversy has occurred on the use of insecticides. Over-reliance and non-

judicious use of synthetic pesticides principally insecticides over the last four to

five decades has resulted in cropping up of many negative consequences mainly

the infamous 3 R’s viz. resurgence, resistance and residue aspects (Mehrotra,

1990; Kabir et al., 1994 ; Mahapatro and Gupta, 1998), besides the health

hazards. Furthermore, their chaotic use has resulted in diminution of biodiversity

of natural enemies (Sekhon and Verma, 1985), outburst of secondary pests

(Praveen et al., 2001), contamination of food (Mitra et al., 1999) and break-

down of food webs in ecosystem (Krishnamurthy, 1999).

Among the various possible substitutes to combat these problems,

biopesticides (plant derivatives and microbial insecticides) are now emerging as

viable components of IPM strategies on all crops in view of the their pesticidal

potency as well as safety to parasitoids and predators (Rao et al., 1999; Salunke

et al., 2000). Besides this, use of resistant/ tolerant crop germplasm (Dhankhar,

1997) and biocontrol agents (Singh, 1993; Singh, 1997; Singh, 2001) are

6

attracting attention these days as imperative tools in IPM. Okra crop is ravaged

by almost the same insect-pests, which attack cotton crop as the two belong to

the same family i.e. Malvaceae. Much consideration is given to cotton crop

whereas okra has largely been overlooked. Keeping in view, the severity of

insect-pests on this crop especially in the Kangra valley of Himachal Pradesh, the

present research was framed. The pertinent literature available on insect-pests of

okra has been appraised in this chapter under the following heads and sub-

heads.

2.1 Insects-pests associated with okra crop

Okra plant is closely related to cotton and ornamental plants. It has

many pests, almost as many as cotton; it being a collateral host. It is also a

preferred host plant for the pests of wild malvaceous plants (Pruthi, 1969;

Maxwell-Lefroy, 1990).

Sharma et al. (1964) reported blister beetle, M. pustulata feeding on

okra flowers. Ananthakrishnan (1971) recorded thrips, Frankliniella dampfi

Priesner and Haplothrips gowdeyi (Franklin) infesting the flowers of lady’s finger.

Various workers have reported A. gossypii, A. biguttula biguttula, Earias spp.,

Dysdercus koenigii Fab., Helicoverpa armigera Hubner, B. tabaci and Spodoptera

littoralis L. as the pests of okra (Mote and Pokharkar, 1974; Gayen, 1975; Gupta

and Dhari, 1978; Babu and Azam, 1982; Krishnakumar and Srinivasan, 1984a;

Singh et al., 1986; Narke and Suryawanshi, 1987; Chaudhary and Dadheech,

1989). Butani and Verma (1976) mentioned as many as 30 pests associated with

7

okra crop, out of which cotton leafhopper (jassid), shoot and fruit borer (spotted

bollworms), red cotton bug, cotton leafroller and red spider mites were listed as

the major pests.

Thippeswami et al. (1980), Nayar et al. (1981), Sharma and Singh,

(1984) and Rajmohana (1999) observed Melanagromyza obtusa (Mall.) infesting

stems of okra plant. Dhamdhere et al. (1984) reported 13 insect and non-insect

pests’ species attacking okra at various stages of crop growth, the major being

A. biguttula biguttula, B. tabaci, S. derogata, Mylabris spp., D. koenigii and E.

vittella. Maxwell-Lefroy (1990) reported that the pests of cotton attack okra crop

as collateral host and listed S. derogata, Myllocerus maculosus B., Earias spp., D.

koenigii, Oxycaraenus laetus Kirkby and A. gossypii as the principal pests

attacking this crop.

Dubey et al. (1999) reported that the summer crop of okra (cv.

Parbhani Kranti) was infested by different insect-pests viz. A. biguttula biguttula,

E. vittella, B. tabaci, H. armigera, A. gossypii, Anomis flava Fab., D. koenigii and

Nezara viridula Linn. and based on their occurrence and infestation; A. biguttula

biguttula, E. vittella, B. tabaci and H. armigera were rated as the major pests.

Flea beetle, Podogrica bowringi Baly was reported as the major pest on okra in

Uttarkashi district of Uttaranchal by Lal (1999). Of the 15 pests recorded on

summer okra crop grown at Dhaulakuan (Himachal Pradesh) by Singh and Joshi

(2004); 4 viz., A. biguttula biguttula, S. derogata, E. vittella and Pectinophora

gossypiella (Saunders) were mentioned as the major pests.

8

2.2 Seasonal incidence/ population build up of insect-pests on okra crop

2.2.1 Sucking pests

Seasonal activity of different pests of okra varies from region to region

due to ecological differences. Seasonal incidence of various pests of okra has

been studied by many workers (Kashyap and Verma, 1982; Mahmood et al.,

1988 and Kandoria et al., 1989). They reported that many pests infested okra

severely during warmer and rainy season i.e. from June to August. Intensity of

damage caused by them also varied from one region to another.

Low humidity was found favourable for the development of A.

biguttula biguttula on okra crop by Dhamdhere et al. (1984) at Gwalior, Madhya

Pradesh. According to Uthamasamy (1988), the incidence of leafhopper (A.

biguttula biguttula) on okra crop was highest on 25th and lowest on 35th day

after sowing at Coimbatore (Tamil Nadu). Further, per cent hopper burn damage

showed a negative correlation (r= -0.57) with the yield whereas leafhopper

infestation and the hopper burn damage on the leaves had a significant positive

correlation (r=+0.43).

The seasonal activity of A. gossypii was studied at Ludhiana (Punjab)

and it was observed that the pest was active on okra crop during September-

October and the population declined from mid- May to the end of June due to

high temperature i.e. 40-45 ˚C (Kandoria et al., 1989). Jamwal and Kandoria

(1990) noticed that at Ludhiana (Punjab), A. gossypii remained active from 4th

week of July to 3rd week of October on okra with a peak population of 450

aphids per 30 plants observed in 1st week of September.

9

Mahmood et al. (1990) reported from Islamabad (Pakistan) that the

leafhoppers started emerging from the month of June on okra and remained

active till the end of crop. They found a positive correlation between the

maximum and minimum temperature and the density count of leafhoppers.

However, relative humidity and rainfall had no noteworthy contribution towards

increasing or decreasing the leafhopper numbers. Devasthali and Saran (1997)

reported from Indore (Madhya Pradesh) that the sucking pests viz. A. biguttula

biguttula, A. gossypii and B. tabaci were the first to appear on okra crop i.e. in

1st week of July.

An experiment was conducted during 1983-91 at Anand (Gujarat) by

Patel et al. (1997a) to study the outcome of weather factors on the activity of

aphid (A. gossypii) and leafhopper (A. biguttula biguttula) infesting okra. They

observed no momentous relationship between the population of aphid and

weather parameters. However, significant positive relationship was observed

between leafhopper level and maximum temperature (r=0.76) as well as hours

of bright sunshine (r=0.82). The population of leafhopper amplified in monsoon

when temperature remained around 37˚C along with at least 10 hours of bright

sunshine.

The highest population of A. biguttula biguttula on okra plants was

observed during 1st week of August in Haryana and numbers were negatively

correlated with maximum temperature but positively correlated with minimum

temperature and average relative humidity (Sharma and Sharma, 1997). At

10

Pundibari (West Bengal), peak population of aphids (A. gossypii) and whiteflies

(B. tabaci) were observed at the end of growth period of okra i.e. in 4th week of

July, while jassid (A. biguttula biguttula) showed its peak population in middle of

June (Ghosh et al., 1999). Gogoi and Dutta (2000) noticed at Jorhat (Assam)

that jassid population was maximum in the last week of May in 1998 (37.53

nymphs/leaf) and middle of April in 1999 (30.00 nymphs/leaf) and low rainfall

period coupled with bright sunshine hours favoured the development of this pest.

Kumawat et al. (2000) reported from Jobner (Rajasthan) that the

infestation of jassids and whiteflies started in 4th week of July and reached peaks

in 2nd and 4th weeks of September, respectively, and maximum temperature was

significantly and positively correlated with whitefly density.

Al Eryan et al. (2001) revealed from Alexandria (Egypt) that A. gossypii

activity started in July on okra and reached its peak in late August (1343.38

aphids/plant). Safdar et al. (2005) noticed that minimum temperature and

relative humidity had significant correlation with whitefly population on okra; the

whitefly population decreased with increase in relative humidity and increased

with increase in minimum temperature at Faisalabad (Pakistan).

2.2.2 Shoot/ fruit borers

Mote (1977) reported from Maharashtra that E. vittella infestation on

okra (var. Pusa Sawani) started as soon as the fruits set and attained a

maximum (69.91%) 3-4 weeks later, after which it dwindled.

11

Radke and Undirwade (1981) noticed the appearance of Earias spp. on

okra in 3rd week of December at Akola (Maharashtra) and reported 100 per cent

infestation in fruits with an average larval population per fruit to be 1.33 when

the average weekly maximum and minimum temperature were 28.1˚C and

10.2˚C, correspondingly, and relative humidity was 56.50 per cent. An increase

of 83.33 per cent was recorded in 1st week of January and beyond 2nd week of

January, 100 per cent fruits were found infested. During this week, average

weekly maximum and minimum temperature were 30.8˚C and 12.1˚C,

respectively, with 49-50 per cent relative humidity.

Kashyap and Verma (1982) reported from Hisar (Haryana) that

population density and incidence of okra spotted bollworm (Earias spp.) was not

correlated with the prevailing temperature, relative humidity or rainfall. They

however, indicated each increase and decrease in pest incidence corresponding

with decrease and increase in temperature and decrease in relative humidity.

Dhamdhere et al. (1984) reported that E. vittella was favoured by high humidity

at Gwalior in Madhya Pradesh.

At Rewa (Madhya Pradesh), summer okra crop was found infested by

stem and shoot fly, M. obtusa and the population was abundant in February and

March. However, there was a decline in the population in last week of April

(when okra stems became hard) and by the end of April, the population almost

ceased because of scorching heat and inability of the pest to oviposit in hard

stems (Sharma and Singh, 1984).

12

Studies on the seasonal incidence of shoot and fruit borer on okra at

Dapoli (Maharashtra) by Madav and Dumbre (1985) revealed that during hot

weather season, an incidence was spotted during 2nd week of March, which

increased progressively and reached its peak (37 % fruit infestation) during 1st

week of April, after which it declined. No incidence was detected throughout the

kharif season. During rabi season, the pest activity started in last week of

November, increased steadily and reached its peak in last week of December

after which it diminished.

At Rahuri (Maharashtra), infestation of E. vittella was highest from 7th

to 20th meteorological week (50.63% in summer season). It was low to moderate

from 21st to 40th meteorological week (24.23% in rainy season). Thereafter, it

increased rapidly and reached its peak, becoming severe (54.56%) in 45th to 52nd

meteorological week (November-December). There were significant and negative

correlations between pest infestation, relative humidity and rainfall (Kadam and

Khaire, 1995).

Shukla et al. (1997) studied seasonal incidence of E. vittella in summer

okra crop at Jabalpur (Madhya Pradesh) and reported the peak shoot damage

before fruiting (8.5 %) and peak fruit infestation (41.25 %) before harvesting in

1st fortnight of June. An experiment conducted at Samastipur (Bihar) to forecast

the okra shoot and fruit borer damage (weight basis) in relation to weather

factors revealed that the minimum incidence (3.2%) was recorded in last week

of May and the maximum (32.1%) in 4th week of July. Significant positive

13

relationships with the minimum temperature (r=0.8245), total rainfall (r=0.3387)

as well as significant negative correlation with maximum temperature (r=-

0.6194) were observed (Gupta et al., 1998).

Studies carried out during kharif 1996 and 1997 on okra cv. Parbhani

Kranti at Anand in Gujarat revealed that the activity of E. vittella started from 3

and 4 weeks age of crop and remained in accelerated mode until removal of

crop. Further, bright sunshine hours and maximum and mean temperature

showed a significant positive, whereas mean vapour pressure and relative

humidity showed significant negative influence on larval activity in okra (Zala et

al., 1999).

Ahmad et al. (2000) reported from Samastipur (Bihar) that peak larval

population (185.7) of E. vittella in fruits of Parbhani Kranti cultivar was noticed

during 1st fortnight of July at 29.9˚C, 84 per cent relative humidity and 61.4mm

precipitation. In a field experiment at Mohanpur (West Bengal), damage by E.

vittella on okra shoots and fruits occurred on 3 and 6-weeks old crop,

respectively, with two peaks of the pest, one at the vegetative stage (2nd

fortnight of August) and other at reproductive stage (2nd week of September)

(Naresh et al., 2003).

At Samastipur (Bihar), the activity of E. vittella on summer okra crop

was observed from 35 days age of the crop. The infestation on shoots ranged

from 0.3 to 3.46 per cent in 2000 and 1.45 to 4.86 per cent in 2001. Maximum

temperature had negative effect while minimum temperature, relative humidiy

(morning and evening) and rainfall had positive effect on larval population and

fruit damage (Mandal et al., 2006b).

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2.2.3 Foliage/ flower pests

Blister beetle, M. pustulata is a polyphagous pest reported to feed on

floral parts of Ipomoea spp., maize, musk-melon, okra, olive, pearl-millet, red

gram, rice, sorghum, watermelon etc. (Sharma et al., 1964; Yadav et al., 1977;

Anand, 1979; Nair, 1984; Garg, 1985). Sharma et al. (1964) reported that the

blister beetle appeared in July and its population peaked in August in Himachal

Pradesh on various crops including okra.

Sangha and Mavi (1995) reported from Ludhiana (Punjab) that M.

pustulata appeared in 2nd fortnight of July during 1990 and 1991 on various

crops, population peaked in mid-August and the activity ceased on November

18th and 14th, during the respective years.

Devasthali and Saran (1997) reported from Indore (Madhya Pradesh)

that A. flava appeared on okra in 3rd week of July. At Pundibari (West Bengal), S.

derogata infestation on okra started in the end of July, showed its peak

population in 2nd week of July, and declined in the month of August (Ghosh et

al., 1999).

2.3 Screening of okra germplasm for resistance against insect- pests Okra is cultivated throughout the country mainly during spring-summer

and rainy season. Considerable native diversity in cultivated and wild types occur

in Indian sub-continent. The available variability including both indigenous and

exotic germplasm has been utilized to a considerable extent in the improvement

of okra. The varietal resistance is a vital tool of integrated pest management. It

15

is quite important component in crops such as okra, in which fruits are picked at

short intervals, hence, the spray of insecticides becomes not only uneconomical

but hazardous also (Sardana and Dutta, 1989). It suppresses pest population

with least disturbance to crop ecosystem and also reduces need for harmful

pesticides that pollute the environment. Host plant resistance is rated as top

priority for IPM. It is highly effective based on cost-benefit analysis and play an

important role in sustaining productivity (Dhaliwal and Arora, 2003). It is a very

effective strategy to manage both direct damage produced by insects and

indirect damage produced by insect-transmitted plant pathogens.

Plant morphology is known to play an important role in imparting

resistance or susceptibility to a cultivar. Physical appearance of the plant like

colour, hairiness, hardness, trichomes, surface waxes, incrustation of minerals in

cuticle and anatomical adaptation of organs may affect the preference or non-

preference for egg laying, feeding and development of an insect (Dhankhar,

1997). In addition, wide array of chemical substances including inorganic

chemicals, primary metabolites, intermediary metabolites and secondary

substances are known to render cultivars less suitable or unsuitable to a wide

array of insect-pests (Dhaliwal and Arora, 2003).

2.3.1 Sucking pests

Positive correlation of jassid incidence with plant height and stem

thickness was reported in okra by Uthamasamy et al. (1973). Bindra and Mahal

(1979) and Mahal et al. (1993b) revealed that okra varieties having dense and

longer hair on mid-vein of leaves imparted resistance against oviposition by A.

16

biguttula biguttula. Uthamasamy and Subramaniam (1980) rated A.E.22 and

Pusa Sawani as highly resistant and susceptible to leaf hopper (A. devastans),

respectively, in Tamil Nadu. Of the 29 varieties of okra and 7 F1’s screened in

Rahuri fields (Maharashtra) against A. biguttula biguttula during late summer and

rainy seasons of 1977; White Velvet, Clemson Spineless, Early Long Green, AE

27 and IC 75 showed less jassid population (Teli and Dalaya, 1981b).

At Hisar (Haryana), out of 44 promising F5 lines of okra tested for

resistance, HB-45, HB-39 and HB-43 were the most resistant to A. biguttula

biguttula (Kishore et al., 1983). In further studies, Uthamasamy (1986)

discovered that the resistance in okra varieties to leafhopper is governed by non-

preference and antibiosis mechanisms. The variety A.E. 22 was less preferred for

oviposition and feeding compared to the susceptible variety, Pusa Sawani. In

addition, the rate of multiplication of the insects on resistant variety was low

compared to the susceptible variety.

It was observed that the okra varieties having more and longer hairs

on the mid-rib and leaf lamina were resistant to leafhopper, rather than those

having more hair density (Singh, 1988; Singh and Agarwal, 1988). These

research workers also reported that the jassid resistant varieties had higher total

sugar, non-reducing sugars, tannins and silica in the leaves. Roy (1990) tested 5

varieties of okra in Orissa fields and found that Selection 2-2 was the least

susceptible to A. gossypii (because of its thick leaves) and Selection-1 was the

most susceptible.

17

Mahal et al. (1991, 1993a) studied the development and survival of

nymphs of A. biguttula biguttula at various ages of okra crop (1, 2, 3 and 4-week

old plants) on different varieties. They observed that varieties IC 7194 and New

Selection exhibited prolonged development and reduced survival of nymphs as

compared to Pusa Sawani at various ages of crop plant. They suggested that 1-

week was the optimum age of okra plant for screening of germplasm based on

the development and survival of jassid nymphs.

In Laguna (Philippines), length and density of trichomes and leaf

surface toughness were significantly greater in the moderately jassid resistant

okra Accession-12. Further, it was found that leaf thickness and number of

trichome branches did not differ significantly, while mid-rib width was

significantly narrower in the susceptible variety, Smooth Green. It was concluded

that long dense leaf trichomes probably impeded feeding and egg deposition and

the greater quantity of readily utilizable free sugar may have led to the greater

attraction and fecundity of the hoppers on Smooth Green (Taylo and Bernardo,

1996).

Based on nymphal abundance and leafhopper injury index, 2 resistant

(Siswal Local and IC 7194) genotypes were identified at Hisar (Haryana) while

Pusa Sawani and Pusa Reshmi were rated as highly susceptible. Further, the

resistance to leafhopper was associated with higher trichome density, longer

trichome length and higher concentration of sugars, silica, potassium, tannins

and phenols in the leaves of resistant cultivars (Hooda et al., 1997).

18

Six okra varieties viz. Parbhani Kranti, Arka Anamika, LBH-55, H-7,

Amtala hybrid and Kamdhenu were tested at Pundibari (West Bengal) for

resistance against major insect-pests of okra viz. aphids, jassids and whitefly. It

was found that both Arka Anamika and Parbhani Kranti showed moderate

resistance against aphids, jassids and whitefly (Ghosh et al., 1999). Among the

different okra varieties evaluated for resistance to A. biguttula biguttula, Pusa

Sawani was observed to be the most susceptible recording lowest fruit yield

(Sharma et al., 2001).

Of the 9 okra cultivars tested for resistance against leafhopper (A.

biguttula biguttula) and red cotton bug (Dysdercus sp.) by Srinivasa and

Sugeetha (2001), KS 410 registered the lowest number of hoppers, while GOH- 1

was the most preferred by hoppers. Further, Arka Abhay and GOH- 1 recorded

low number of bugs while Parbhani Kranti and KS 410 recorded high bug

population. At Faizabad (Uttar Pradesh), Kumar and Singh (2002) revealed that

the pooled (2 seasons) nymphal population of A. biguttula biguttula was lowest

in Punjab Padmini (1.87) followed by DOV-91-4 (1.96) and Arka Anamika (1.98)

and highest in Pusa Sawani (3.77). The lowest leaf injury was recorded in Arka

Anamika (12.61%) followed by Punjab Padmini (13.27%) and highest in Pusa

Sawani (61.06%).

Out of 25 cultivars of okra tested in Palayamkottai (Andaman and

Nicobar islands), against the mite, Tetranychus cinnabarinus (Boisduval); EC

28427, IC 141065, IC 90049 were rated resistant and EC 329364, IC 140977, TC

19

90074 were rated moderately resistant. The resistance level was based on low

moisture and more phenol content and more number of glandular hairs on the

leaves of resistant cultivars (Sahayaraj et al., 2003).

2.3.2 Shoot / fruit borers

Some of the genotypes of okra reported relatively tolerant to shoot

and fruit borer by Srinivasan and Narayanaswamy (1961) were Bhendi Red-1,

Bhendi Red-11 and Red Wonder. Late flowering varieties of okra irrespective of

hairiness were reported susceptible to fruit borer (Gupta and Yadav, 1978).

Raut and Sonone (1979) evaluated 25 cultivars and 2 related wild

species of okra with respect to shoot and fruit borer, E. vittella resistance at

Rahuri (Maharashtra). They found minimum infestation of fruits in cultivar,

Wonderful Pink (11.68%) while the variety Pusa Sawani was highly susceptible

(42.39 % infested fruits) and the wild species, A. mannihot and H. tetraphyllus

were respectively immune and highly resistant to the attack of pest.

Among 72 genotypes of okra screened against Earias spp. under field

conditions at Hisar (Haryana), Narnaul Special, 6(2), Harbhajan, Clemson

Spineless, White Snow and Sel Round revealed less than 10 per cent infestation

while the remaining genotypes exhibited 10-50 per cent infestation (Kashyap and

Verma, 1983).

Studies on relative susceptibility of different cultivars of okra for 2

seasons at Dapoli (Maharashtra) revealed that none of the cultivars was resistant

to shoot and fruit borers. The cultivars viz. A.E.-75, Pusa Sawani, Long Green,

20

Indo-American hybrid and White Velvet were tolerant showing 21-30 per cent

shoot infestation. However, based on fruit infestation, all the cultivars were

either susceptible or highly susceptible except A.E.-75 which was tolerant (Madav

and Dumbre, 1985).

Singh et al. (1986) found P-8 and Ludhiana Selection-2 genotypes

resistant to okra shoot and fruit borer. Tannin content in the fruit pericarp of fruit

borer tolerant okra genotypes was higher than susceptible genotypes (Singh and

Singh, 1987). Ninety nine okra genotypes were screened for resistance to Earias

spp. at Hisar (Haryana) and it was found that number of infested fruits per plant

were lowest in cultivar, Long Green Smooth (14.4%) followed by All Season

(14.5%), Sel 2-2 (15.0%), IC 6497 (15.2%) and IC 6316 (15.5%) (Sharma and

Dhankhar, 1989).

Okra varieties viz. AE 79, AE 69 and AE 22 screened at Rahuri

(Maharashtra), demonstrated high resistance to shoot borer (in terms of number

of dying plants and per cent fruit infestation) and resistance to fruit infestation

was correlated with increased fruit hair density (Kumbhar et al., 1991). Among 5

okra varieties tested for their reaction to fruit borer at Jachh (Himachal Pradesh),

maximum incidence was observed on P-8 followed by Harbhajan, Parbhani

Kranti, Punjab 7 and Pusa Sawani (Raj et al., 1993).

Shukla et al. (1998) conducted field trials in 2 different locations at

Jabalpur (Madhya Pradesh) to test 7 okra varieties/ hybrids for resistance to E.

vittella. They concluded that varieties AROH 2 and Komal hybrid F1 showed

21

lowest shoot damage (4 and 5 %, respectively) but were poor yielders (27.80

and 19.70 qha-1, respectively). Variety Ankur 35 and Parbhani Kranti however,

registered significantly higher shoot damage (7.5 and 8.0 %) but produced

higher healthy fruit yields of 72.81 and 62.06 qha-1, respectively.

Six okra varieties viz. Parbhani Kranti, Arka Anamika, LBH-55, H-7,

Amtala hybrid and Kamdhenu were tested at Pundibari (West Bengal) for

resistance to fruit borers. It was discovered that fruit damage due to borer varied

between low to moderate (7.73-10.10%) on all the varieties (Ghosh et al.,

1999). Nine okra cultivars were evaluated for resistance to Earias spp. during 2

season trial conducted by Srinivasa and Sugeetha (2001) at Bangalore

(Karnataka). It was observed that none of the cultivars was completely free from

infestation, the most susceptible variety being GOH-1.

Naresh et al. (2003) observed in field experiments at Mohanpur (West

Bengal) that Vijaya cultivar was less susceptible based on shoot damage by

Earias spp., however, fruit damage was lowest in Hybrid No. 8 followed by Jaya,

OH-1, Arka Abhoy, Harsha, Vijaya, Arka Anamika and Soumya. Neeraja et al.

(2004) screened some okra hybrids against fruit borer at Rajendranagar

(Hyderabad) and reported that the fruit borer incidence ranged from 21.7 per

cent in MBORH-913 to 27.6 per cent in JNDOH-1. Singh et al. (2005b)

determined the resistance of 20 okra germplasm lines against E. vittella at

Faizabad (Uttar Pradesh). They revealed that KS-410, A-4 and NDO-10 showed

lower damage on shoots as well as fruits.

22

2.3.3 Foliage/ flower pests

Six okra varieties viz. Parbhani Kranti, Arka Anamika, LBH-55, H-7,

Amtala hybrid and Kamdhenu were tested at Pundibari (West Bengal) for

resistance against leafroller, S. derogata. It was found that both Arka Anamika

(1.07 larvae/plant) and Parbhani Kranti (0.32 larva/plant) showed moderate

resistance to this pest (Ghosh et al., 1999).

Naresh et al. (2003) screened 8 okra cultivars at Mohanpur (West

Bengal) for resistance to leafroller and found that the order of susceptibility was:

Arka Anamika < Vijaya < Hybrid No.8 < OH-1 < Arka Abhoy < Jaya < Soumya <

Harsha.

2.4 Management of insect pests

2.4.1 Seed treatment

Application of insecticides to seeds before or at the time of planting

offers the most proficient and concentrated means of protecting the germinating

seeds and seedlings. Such applications are minimal in dosage and highly

economical as well as least disturbing to the environment. Seed treatment with

systemic insecticides like phorate and disulfoton protects the seedlings from the

attack of aphids, thrips and leafhoppers for several weeks (Metcalf, 1975). It is

an effective method for managing sucking pests on okra which occur at an early

stage of crop growth. Moreover, the seed treatment is superior to foliar sprays in

rainy season too (Mote et al., 1994). Clayton (1988) suggested seed treatment

23

technology to replace wasteful foliar or soil application in order to reduce the

environmental impact of agro-chemicals. A new insecticide, imidacloprid

belonging to the group of nitroguanidines has been tried recently (Kumar and

Dixit, 2001) as seed dresser against sucking pests of okra and found efficient.

Mote et al. (1994) found imidacloprid (15 g kg-1 seed) treatment

promising against sucking pests of okra viz. aphids, jassids, thrips, mites and

whiteflies at Rahuri (Maharashtra). Okra seed treatment with Gaucho

(imidacloprid) 70 WS or Cruiser (thiomethoxam) 70 WS at 5 and 4.29 g kg-1

seed, respectively, kept pest population of A. biguttula biguttula below economic

threshold level (2.5 nymphs/ leaf) for more than 45 days (Sharma and Kalra,

1996).

Sreelatha and Divakar (1997) in an experiment conducted at

Rajendranagar (Hyderabad) revealed that seed treatment with imidacloprid (7.5

g kg-1 okra seed) effectively suppressed aphids and jassids besides increasing

the plant height, leaf area and yield of okra. They further reported that 2 foliar

sprays during vegetative stage of crop could be avoided if the seed is treated.

Bhargava and Bhatnagar (2001) revealed that 2 formulations of

imidacloprid 600 FS at the rate of 9 ml kg-1 and 70 WP at the rate of 10 g kg-1

okra seed treatment performed well against jassids and whiteflies at Jaipur

(Rajasthan) recording higher yields with no phyto-toxic symptoms on crop.

24

Kumar and Singh (2001) reported from Bangalore (Karnataka) that

seed treatment with imidacloprid (Gaucho 600 FS) at 12 ml kg-1 was efficient in

reducing leafhopper infestation with no phyto-toxic effect on okra plants;

however, the lower concentrations were not effective. Seed treatment of okra

with imidacloprid (5g kg-1) managed population of A. biguttula biguttula

successfully at Hisar in Haryana (Lal et al., 2001).

In field experiments conducted at New Delhi, okra seed treatment with

imidacloprid (3 or 5.4 g a.i. kg-1 seed) was found effective in managing A.

biguttula biguttula population (Sinha and Sharma, 2007).

2.4.2 Foliar application

2.4.2.1 Botanicals

Among the various plant products studied during the last 25 years,

extracts and compounds from neem tree (Azadirachta indica A. Juss) have

attracted a special contemplation of entomologists all over the world. Neem is

known to contain assorted array of biologically active principles, of which

azadirachtin is one of the best known ingredients (Singh, 1996). Neem has

antifeedant, antiovipositional, growth disrupting and fecundity reducing

properties for different insects (Singh, 1984; Schumutterer, 1990; Schumutterer,

1995) and is suitable for inclusion in integrated pest management programmes.

Neem and neem products have been reported to check population of more than

200 species of insects belonging to different orders like coleoptera, diptera,

lepidoptera, heteropotera, homoptera, orthoptera and thysanoptera

(Ramarethinam, 1998).

25

More than 68 neem (A. indica) based formulations are now

commercially available in India (Srinivasamurthy, 1998) which have been largely

tested and used against number of insect-pest species on various crops as

compared to other botanical pesticides. Furthermore, the chances of developing

resistance in insects to neem preparations are very less. Such preparations are

also comparatively more economical, biodegradable, and safe to human beings

and beneficial insects.

2.4.2.1.1 Sucking pests

Neem oil (2%) failed to provide any noteworthy suppression of okra

leafhopper population compared to check insecticide, monocrotophos, 0.05 per

cent at Bangalore, Karnataka (Sardana and Kumar, 1989). At Anand (Gujarat),

okra crop sprayed with botanicals viz. neemark (1.0%), neemol (1.0%) and

neem seed kernel suspension showed oviposition deterrent and growth inhibitory

effect on jassids and resulted in lower percentage of normal adult emergence

(Patel and Patel, 1996).

In Nairobi, population of A. gossypii was effectively checked on okra by

4 weekly sprays of 0.5 per cent aqueous neem seed extract or 2 per cent neem

oil, the results being at par with butocarboxim insecticide (Dreyer and Hellpap,

1997). Aqueous leaf extracts of tobacco (2%), Ipomoea carnea (5%) and seed

extracts of A. indica and Pongamia glabra (both at 5%) gave a similar level of

suppression of A. devastans and A. gossypii on okra as that by endosulfan

(0.06%) and monocrotophos (0.05%) at Nagpur in Maharashtra (Kulat et al.,

1997).

26

Patel and Patel (1998) revealed that Repelin (formulation based on A.

indica) at 1 per cent was highly effective in managing A. biguttula biguttula on

okra under Gujarat conditions. Thakur and Singh (1998) reported from

Dhaulakuan (Himachal Pradesh) that neem compounds viz. achook, niconeem

and neemark failed to provide effective decrease of jassids on okra.

At Varanasi (Uttar Pradesh), 2 sprays of neem at the rate of 2.5 ml l-1

during vegetative phase of the okra crop were less effective compared to

synthetic chemicals and their combinations tested against jassids (Satpathy and

Rai, 1999). Two sprays of neemitaf (azadirachtin 6 ppm; 4ml l-1) on okra crop at

Coimbatore (Tamil Nadu) at an interval of 15 days were rated relatively

ineffective against A. gossypii (Chinniah and Ali, 2000).

In an experiment conducted by Kumar and Singh (2001) at Faizabad

(Uttar Pradesh), the efficacy of some botanicals was evaluated against A.

biguttula biguttula infesting okra crop. It was observed that both achook

(0.07%) and neem seed kernel extract (NSKE - 3%) were effective in checking

jassid population and out of these, NSKE (3%) witnessed the most economical

cost: benefit ratio (1:10.7). Rosaiah (2001) conducted field experiments at

Guntur (Hyderabad) to evaluate the performance of various botanicals against

the pest complex of okra for 3 consecutive years (1995-97) and showed that

NSKE (5 and 10 %) and neemazal (0.5%) were less effective in reducing jassid

population.

The plant product azadirachtin at the rate of 3 g a.i. ha-1 was reported

effective against okra aphids but not against jassids by Mishra (2002) at

Bhubneshwar (Orissa). Mishra and Senapati (2003) reported from Bhubneshwar

27

(Orissa) that azadirachtin (3 g a.i. ha-1) resulted in optimum reduction in

population of jassids on okra (55.50 % reduction over untreated check).

Aqueous neem seed extract (50g l-1) reduced the population of D. superstitious

and B. tabaci on okra and produced higher fruit yield in Ghana thus concluding

that this botanical can be lucratively used by farmers as an element of integrated

pest management (Obeng and Sackey, 2003). Panickar et al. (2003) reported

from Anand (Gujarat) that 3 sprays of achook (0.15% EC) starting from 45 days

old crop of okra registered substantially lower aphid population.

Mudathir and Basedow (2004) observed that neem preparations viz.

neem kernel water extract (NKWE) containing 2.5-5.0 per cent azadirachtin a.i.

ha-1 and neemazal containing 6-12 per cent azadirachtin a.i. ha-1 appreciably

abridged the attack of A. gossypii and B. tabaci on okra in Sudan. Safdar et al.

(2005) reported that neem extract significantly lowered the whitefly (B. tabaci)

population on okra at Faisalabad (Pakistan).

2.4.2.1.2 Shoot / fruit borers

Among the various plant oils evaluated against E. vittella at Bangalore

(Karnataka), neem oil (2%) proved to be the best in reducing the borer damage

on okra (Sardana and Kumar, 1989). Repelin (1.0%), neemark (0.1%) and

neem oil (1.0%) provided good reduction of E. vittella on okra (Sojitra and Patel,

1992). Four sprays of achook (1.0%) and neem oil (1.0%) provided good check

of E. vittella infestation on okra at Jabalpur (Madhya Pradesh) (Shukla et al.,

1996). NSKE (3%) was found equally effective as chlorpyriphos (0.04%),

triazophos (0.04%) and quinalphos (0.025%) in giving protection to okra fruits

against E. vittella at Anand in Gujarat (Patel et al., 1997b).

28

Neem seed kernel extract was reported ineffective in managing E.

vittella on okra at Akola (Maharashtra) by Sarode and Gabhane (1998). Singh et

al. (1998) reported from Udaipur (Rajasthan), that 3 foliar sprays of both neem

seed extract (100%) and neem seed oil (1 kg ha-1) were effective against Earias

spp. on okra.

Compared to synthetic chemicals and their combinations tested against

fruit borers on okra at Varanasi (Uttar Pradesh), neem sprays at the rate of 2.5

ml l-1 were less effective (Satpathy and Rai, 1999). Ambekar et al. (2000a)

reported from Pune (Maharashtra) that achook (0.5%) was the best in reducing

okra fruit borer infestation among the various neem products viz. NSKE, achook,

nimbecidine, rakshak, bioneem, nimbitor, neemgold and neemark tested against

this pest. Three neem preparations viz. NSKE (5%), nimbitor (0.5%) and achook

(0.5%) when used alone were less efficient than synthetic pesticides against

okra fruit borer and recorded 27.25, 28.38 and 29.58 per cent fruit borer

infestations, respectively, at Pune (Maharashtra) (Ambekar et al., 2000b).

Anaso and Lale (2002) reported from Maiduguri (Nigeria) that okras

sprayed with aqueous neem kernel extract harboured appreciably less population

of H. armigera. In field trials at Bapatla (Andhra Pradesh), Gowri et al. (2002)

revealed that nimbecidine (1.0%) was quite effective against E. vittella and gave

higher okra yields. Neem preparations viz. neem kernel water extract (2.5-5.0 %

azadirachtin a.i. ha-1) and neemazal (6-12% azadirachtin a.i. ha-1) noticeably

reduced the attack of E. vittella on okra at Khartoum North in Sudan (Mudathir

and Basedow, 2004).

29

Five sprays of NSKE (1.5%) gave good reduction of E. vittella on okra

at Faizabad (Uttar Pradesh) and recorded higher fruit yield of 56.33 qha-1

compared to 29.17 qha-1 in untreated check (Singh et al., 2005a). Gupta and

Mishra (2006) reported from Pusa (Bihar) that neem oil (0.5%) failed to provide

effective decrease in E. vittella incidence and was at par with untreated check.

2.4.2.1.3 Foliage / flower pests

Cobbinah and Owusu (1988) found in Ghana that okra plants treated

with neem seed extracts harboured lower population of S. derogata and P.

sjostedti. Neem products viz. 3 per cent neem oil and 5 per cent NSKE were

found effective against flea beetles, P. uniformis and P. sjostedti on okra in

Lalabar (Nigeria) and gave higher yields (Emosairue and Ukey, 1997). Both these

neem products showed promise as a substitute for synthetic insecticides for the

management of these pests. Further, it was suggested that higher concentration

and closer spray regimes would probably improve their efficacy.

Anaso and Lale (2002) reported from Maiduguri (Nigeria) that okras

sprayed with aqueous neem kernel extract recorded appreciably less population

of Podogrica spp. and S. derogata. At Bhubneshwar (Orissa), azadirachtin (3g

a.i. ha-1) was observed effective (Mishra et al., 2002) in managing okra

leafrollers with least per cent infestation (1.2-2.0%) as compared to untreated

check (12.4%). Obeng and Sackey (2003) revealed from Ghana that aqueous

neem seed extract (50g l-1) reduced the population of P. uniformis, S. derogata,

Epilachna similis, S. littoralis and S. litura on okra and produced higher fruit yield.

30

Neem preparations viz. neem kernel water extract (NKWE) containing

2.5-5.0 per cent azadirachtin a.i. ha-1 and neemazal containing 6-12 per cent

azadirachtin a.i. ha-1 significantly reduced the attack of P. punticollis on okra at

Khartoum North in Sudan (Mudathir and Basedow, 2004).

2.4.2.2 Microbial insecticides

Microbial insecticides are basically pest management agents of

biological origin, including bacteria, fungi and viruses. These provide viable and

ecofriendly alternative to chemical insecticides for the successful management of

insect-pests on a variety of crops. Among these, bacterium, Bacillus thuringiensis

Berliner plays a very important role in natural mortality of the larvae. Falcon

(1971) reported 23 strains of B. thuringiensis used in insect management. This

bacterium is currently being used worldwide, mainly for the management of

lepidopterous, coleopterous and dipterous pests (Jaques, 1988; Biswas et al.,

1996; Sharma and Odak, 1996; Elanchezhyan et al., 2007).

Bt based bioinsecticides account for 90-95 per cent of the world

biopesticides market (Asokan et al., 2001). This bacterium acts on host through

delta endotoxin crystals which are stomach poisons (Elanchezhyan et al., 2007).

Many bacterial formulations such as Halt, Dipel, Bioasp, Biobit, Delfin etc are

available in the market for the management of lepidopterous insect-pests on

vaious crops.

31

2.4.2.2.1 Sucking pests

Ghosh et al. (1999) inferred that Bt (1g l-1) recorded 32.14 per cent

mortality of jassids and 35.35 per cent mortality of aphids on okra at Pundibari

(West Bengal). They further reported that vertimec, a microbial toxin originated

from a soil actinomycetes was more effective than synthetic insecticides viz.

malathion and DDVP and biopesticides viz. Bt and Beauveria bassiana (Bals.)

Vuill. against both these sucking pests.

Obeng and Sackey (2003) reported from Legon (Ghana) that sprays of

Bt (1g l-1) on okra substantially dropped off the damage caused by B. tabaci and

D. superstitious and produced higher yields of marketable fruits, thus

emphasising that this biopesticide can be effectively used by farmers as a

component of IPM of okra.

In a field experiment conducted at Samastipur (Bihar), 3 sprays of Bt

(500g ha-1) on okra were effective in reducing the jassid population and this

treatment was at par with the monocrotophos treatment (Mandal et al., 2006a).

2.4.2.2.2 Shoot/ fruit borers

Foliar applications of dipel at 0.5, 1.0 or 1.5 lb acre-1 in Nigeria

effectively checked infestation of H. armigera, E. insulana and E. biplaga on okra

(Taylor, 1974). Three weekly sprayings with dipel (0.5 kg ha-1) on okra in

Karnataka effectively managed E. vittella (Krishnaiah et al. 1981). Mohan et al.

(1983) reported sprays of dipel (0.5 kg ha-1) equally effective as fenvalerate (0.1

kg a.i.ha-1) in suppressing E. vittella infestation on okra at Bangalore

(Karnataka).

32

Three sprays of either B. thuringiensis var. kurstaki-1 (BTK-1) at the

rate of 1.5 kg a.i. ha-1 or B. thuringiensis var. thuringiensis (BTT) at the rate of

1.5 kg a.i.ha-1 were found effective in reducing the fruit infestation by Earias spp.

on okra crop at Udaipur (Rajasthan) (Singh et al., 1998).

The commercial formulation of B. thuringiensis (dipel) at the rate of

0.1 per cent was least effective in reducing okra shoot and fruit infestation by E.

vittella over untreated check at Bilaspur (Madhya Pradesh) (Tomar, 1998).

Among the various pesticides tested against fruit borer on okra in West Bengal

by Ghosh et al. (1999), vertimec (formulation based on microbial toxin originated

from a soil actinomycete) and B. thuringiensis proved superior over synthetic

pesticides (Malathion, DDVP) and biopesticides (neem, B. bassiana) in reducing

fruit damage by borer i.e. 57.80 and 50.12 per cent, respectively.

Karim et al. (2000) reported from Pakistan that B. thuringiensis

formulations- Agree and Larvo Bt (250-1500 g a.i. ha-1) were effective against H.

armigera and E. vittella on okra crop. Lal et al. (2001) found that B. thuringiensis

(0.5 kg ha-1) sprays at weekly intervals was effective in checking E. insulana

infestation on okra.

At Rahuri (Maharashtra), sprays of B. thuringiensis (0.03%) on okra

crop did not prove effective against fruit borer. However, alternate spraying of

cypermethrin, followed by NSE followed by B. thuringiensis recorded the lowest

fruit damage i.e. 15.33 per cent (Patil et al., 2002). According to Gupta and

Mishra (2006), sprays of Spicturin (Btk 0.3%) gave good protection to okra crop

33

from E. vittella infestation at Pusa (Bihar). Likewise, Mandal et al. (2006a)

reported from Samastipur (Bihar) that 3 sprays of Bt (500g/ha) significantly

reduced fruit infestation by E. vittella over untreated check.

2.4.2.2.3 Foliage/ flower pests

Taylor (1974) investigated in Nigeria that foliar applications of dipel at

0.5, 1.0 or 1.5 lb acre-1 successfully managed population of S. derogata, A. flava

and S. littoralis on okra. Vetimec, proved its superiority over synthetic pesticides

in decreasing the larval population of leafroller on okra (Ghosh et al., 1999).

In Legon (Ghana), sprays of B. thuringiensis (1g l-1) significantly

decreased the damage caused by P. uniformis, S. derogata, E. similis, S. littoralis

and S. litura on okra (Obeng and Sackey, 2003) and produced higher yield of

marketable fruits thereby concluding that this biopesticide can be efficiently used

by farmers for integrated pest management in okra.

2.4.2.3 Synthetic pesticides

One cannot ignore the harmful effects of synthetic pesticides reported

in almost every component of biosphere. Moreover, in crops such as okra, the

short interval between picking of fruits poses the residue hazards to the

consumers when the chemical insecticides are used. Nevertheless. it is to be

confessed by one and all that when used properly, pesticides provide an

efficient, fast, reliable and cost-effective means of pest management

(Mahapatro, 1999).

34

2.4.2.3.1 Sucking pests

Satpathy and Mishra (1970) suggested sprays of endosulfan for

suppressing population of okra jassids. Field trials for 3 successive years (1973-

75) on rainfed okra crop at Kanpur (Uttar Pradesh) revealed that 4 sprays of

malathion (0.04%), 2 at vegetative and 2 at fruiting stage were effective in

checking jassid population (Gupta and Dhari, 1978). Mote (1978) reported from

Rahuri, that first 2 sprays on okra crop with 0.03 per cent monocrotophos and

dimethoate at an interval of 15 days starting from 2 weeks after sowing and next

3 sprays with 0.05 per cent endosulfan at fortnightly intervals starting from fruit

setting were effective for the management of A. devastans.

At Hisar (Haryana), Singh and Chopra (1979) found malathion 0.1 per

cent effective against okra jassids upto 12 days after spraying. Parkash et al.

(1980) noticed at Hisar (Haryana) that 1 spray of 0.03 per cent dimethoate/

phosphamidon during prefruiting stage followed by 4 fortnightly sprays of

phosalone (0.1%) or malathion (0.1%) or endosulfan (0.05%), during the

fruiting stage were effective against A. biguttula biguttula on okra crop. Three

sprays of endosulfan (310g a.i. ha-1) were at par with 5 sprays of malathion

(700g a.i. ha-1) in managing A. biguttula biguttula population on okra at

Ludhiana in Punjab (Singh et al., 1982). It was also noticed that higher yields

were obtained when the crop was sprayed at an infestation level of 5 nymphs

per leaf.

35

A field experiment conducted at Bangalore (Karnataka) by Mohan and

Mohan (1985) revealed that endosulfan (0.7 kg a.i. ha-1) was quite effective for

the suppression of A. biguttula biguttula and A. gossypii population on okra crop.

Rai (1985) revealed from field trials conducted at New Delhi on management of

okra pests that decamethrin (0.0065%) gave maximum reduction in jassid

population but was statistically at par with cypermethrin at both the doses

(0.017%; 0.00325%), whereas, chlorpyriphos (0.048%) was the most effective

against aphids but did not differ statistically from cypermethrin (0.034%) and

decamethrin (0.0065%).

Yadav et al. (1988) evaluated some insecticides against jassids at Hisar

(Haryana) and signified that 3 sprays of endosulfan (0.05%) provided an

excellent reduction of jassid population on okra throughout the growth period.

The performance of 16 insecticides against the cicadellid, A. biguttula biguttula

on okra was studied at Hisar (Haryana) by Dahiya et al. (1990) during kharif and

it was found that cypermethrin, fenvalerate, flucythrinate (all at 0.006%),

deltamethrin (0.002%) and endosulfan (0.07%) were the most persistent and

effectively checked pest population for 15 days. Further, fenthion, diazinon,

phenthoate (all at 0.05%), malathion (0.075%) and carbaryl (0.1%) were

effective for a week only.

Rao et al. (1991) reported from Bapatla (Andhra Pradesh) that 4

sprays of endosulfan (0.07%) or endosulfan (0.07%) alternated with carbaryl

(0.15%) were quite effective against aphids and leafhoppers infesting okra crop.

36

Singh et al. (1991) revealed from Jammu that deltamethrin (0.0014%, 0.0028%

and 0.0042%) and endosulfan (0.053%, 0.070% and 0.087%) were more

effective than malathion (0.084%) against okra jassids at all the tested dosages.

Okras sprayed with 0.1 per cent endosulfan at Kanpur (Uttar Pradesh)

resulted in 90 per cent mortality of D. cingulatus upto 2 after spraying (Kumar et

al., 1992). Borah (1994) revealed from Diphu (Assam) that application of 0.05

per cent malathion at 15 days after germination followed by 0.03 per cent

dimethoate at 25 and 30 days after germination managed A. biguttula biguttula

effectively and resulted in higher fruit yield of okra.

Kumar et al. (1996) observed that foliar sprays of malathion 50 EC at

400-500 ml acre-1 at Hisar (Haryana) increased okra fruit yield significantly over

untreated check because of the reduction in the population of A. biguttula

biguttula. Sosamma and Sheila (1996) investigated that cypermethrin (0.02%)

was the most effective insecticide against okra aphids and remained effective till

14 days after spraying in field trials conducted at Thrissur in Kerala.

Patel et al. (1997b) conducted field experiments on okra at Anand

(Gujarat) to test the efficacy of some conventional insecticides against A.

gossypii and A. biguttula biguttula. They reported that among the different

insecticidal sprays, endosulfan (0.035%) was most effective against both the

pests. Endosulfan (0.07%) was observed to be highly efficacious in reducing the

population of A. biguttula biguttula on okra in field experiments conducted at

37

Anand (Gujarat) by Patel and Patel (1998). In West Bengal, higher mortality of

aphids (66.19%) and jassids (49.52%) on okra crop was brought about by the

application of malathion (Ghosh et al., 1999).

In Jos (Nigeria), cypermethrin at 12.5 g a.i. ha-1 reduced the

population of Empoasca spp. substantially on treated okra plants than those on

untreated ones (Parh et al., 1999). Two sprays of endosulfan (700 g a. i. ha-1)

during vegetative stage of okra restricted jassid population quite effectively at

Varanasi and Ranchi (Satpathy and Rai, 1999; Singh and Chaudhary, 2001).

Cypermethrin (100 g a.i. ha-1) gave good protection to okra against

aphids and jassids at Bhubneshwar, Orissa compared to thiomethoxam and

imidacloprid (both at 25g a. i. ha-1) which were less effective (Mishra, 2002).

Sherlone (phosalone 24% + cypermethrin 5%) at 360 g a.i. ha-1 was found

effective against A. biguttula biguttula on okra at Bhubneshwar, Orissa by Panda

et al. (2002). Sprays of malathion (0.05%) gave satisfactory reduction in

population of jassids on okra (Sharma and Shukla, 2003) at Jabalpur (Madhya

Pradesh). Mandal et al. (2006a) demonstrated the efficacy of 3 sprays of

monocrotophos 36SL (400g) in managing jassid population on okra in Bihar.

2.4.2.3.2 Shoot / fruit borers

Satpathy and Mishra (1970) advocated the sprays of endosulfan for

the management of okra borers. Three-four sprays of monocrotophos (0.1%) or

endosulfan (0.07%) at 15 days interval were equally effective in checking okra

fruit borer (E. vittella and E. insulana) infestation at Coimbatore in Tamil Nadu

38

(Gopalan et al., 1974; Mote and Pokharkar, 1974; Uthamasamy and

Subramaniam, 1976). Field trials for 3 successive years (1973-75) on rainfed

okra crop at Kanpur (Uttar Pradesh) revealed that 4 sprays of malathion

(0.04%), 2 at vegetative and 2 at fruiting stage were effective in checking shoot

and fruit infestation by E. vittella (Gupta and Dhari, 1978).

Mote (1978) reported from Rahuri, Maharashtra that first 2 sprays on

okra crop with 0.03 per cent monocrotophos and dimethoate at an interval of 15

days starting from 2 weeks after sowing and next 3 sprays with 0.05 per cent

endosulfan at fortnightly intervals starting from fruit setting were effective for

the management of E. vittella and E. insulana. Jadhav and Nawale (1980) in field

experiments conducted at Rahuri and Kolhapur (Maharashtra) revealed that 4

sprays of 0.05 per cent monocrotophos were more effective than endosulfan

(0.05%) in reducing the infestation of fruit borers and getting higher yield of

healthy fruits but keeping in view the environmental safety, endosulfan was

recommended.

At Akola (Maharashtra), sprays of malathion (0.05%) and endosulfan

(0.05%) gave good reduction in fruit infestation by spotted bollworm, E. vittella

on okra (Radke and Undirwade, 1981). According to Kale et al. (1982), sprays of

cypermethrin (15g a.i. ha-1) at an interval of 14 days could be relied upon for

reducing the losses due to E. vittella on okra. Both fenvalerate and cypermethrin

were found effective in checking infestation by E. vittella and H. armigera and

giving higher yields of marketable okra fruits (Krishnakumar and Srinivasan,

1984a; Krishnakumar and Srinivasan 1984b; Patel et al., 1984; Krishnakumar

and Srinivasan, 1985; Krishnakumar and Srinivasan, 1987).

39

Rai (1985) revealed from field trials conducted in New Delhi that fruit

borer of okra was effectively managed by the application of decamethrin

(0.0065%). Field experiments conducted at Kanpur (Uttar Pradesh) indicated

that malathion (0.03 %, 3 sprays) gave satisfactory protection against okra shoot

and fruit borer infestation (Verma, 1985).

Cypermethrin (0.012%) was observed to be promising against the okra

fruit borer, E. vittella by Khaire and Naik (1986) at Pune (Maharashtra). At

Rahuri in Maharashtra, 1 spray of endosulfan at the rate of 500 g a.i. ha-1, 15

days after germination of okra followed by 3 sprays of fenvalerate or

cypermethrin (both at 50 g a.i. ha-1) were quite effective in checking fruit borer

infestation. In addition, this treatment gave the highest yield (73.32 q ha-1)

compared to untreated check (18.14 q ha-1) (Pawar et al., 1988). In field

experiments at Agartala (Tripura), all the tested insecticides viz. malathion,

endosulfan, fenvalerate, deltamethrin were found effective in managing E.

vittella with fenvalerate (0.5 ml l-1) giving the highest reduction in number of

infested okra fruits (Sarkar and Nath, 1989).

At Varanasi (Uttar Pradesh), 2 applications of malathion (1000 ml ha-1)

on okra gave satisfactory reduction of E. vittella and E. insulana incidence (Konar

and Rai, 1990). David and Kumaraswami (1991) reported from Madurai (Tamil

Nadu) that cypermethrin (0.016%) was superiormost in reducing the okra fruit

damage by fruit borer on number as well as weight basis. Rao et al. (1991)

reported from Bapatla (Andhra Pradesh) that 4 sprays of endosulfan (0.07%)

during kharif season or endosulfan (0.07%) alternated with carbaryl (0.15%)

were quite effective against shoot and fruit borers infesting okra crop.

40

Endosulfan (0.350 kg a.i. ha-1) brought about effective suppression of

fruit borer, E. vittella on okra at Padappai (Tamil Nadu) and gave appreciably

higher yield of healthy fruits (Samuthiravelu and David, 1991). Minimum damage

to okra fruits by fruit borers was observed in treatment comprising 4 regular

sprays of endosulfan at an interval of 15 days at Rahuri in Maharashtra (Pawar

and Lawande, 1993). Cypermethrin (0.006%) was found less effective against

the okra fruit borer, E. vittella at Bapatla, Andhra Pradesh by Prasad et al.

(1993). Of the several insecticides tested against E. vittella on okra at Diphu

(Assam), by Borah (1995), malathion (0.05%) applied after 15 days of

germination in combination with dimethoate (0.03%) applied 25 and 30 days

after germination were the most effective and also gave highest marketable

yield.

Kumar et al. (1996) noticed that foliar sprays of malathion 50 EC (400-

500 ml acre-1) at Hisar (Haryana) increased the fruit yield of okra significantly

over untreated check because of reduction in population of E. vittella. At

Jabalpur, Madhya Pradesh, 4 sprays of cypermethrin 10 EC (0.005%) on okra

gave good reduction of E. vittella infestation (Shukla et al., 1996). Patel et al.

(1997b) conducted field experiments on okra at Anand (Gujarat) to test the

efficacy of some conventional insecticides against E. vittella. They reported that

endosulfan (0.035%) was the most effective among the different insecticidal

sprays.

41

Both, monocrotophos (500g a.i. ha-1) and cypermethrin (50g a.i. ha-1)

performed equally well (Rai and Satpathy, 1999) against E. vittella on okra at

Varanasi (Uttar Pradesh). Among the different chemicals tested against E. vittella

on okra at Ranchi (Jharkhand), cypermethrin 25 EC (0.075%, 2 sprays) showed

its superiority in terms of lower fruit infestation and higher cost-benefit ratio over

other chemicals viz. fenvalerate, ethion, cartap hydrochloride, fluvalinate and

endosulfan (Singh and Chaudhary, 1999).

Among the different chemicals viz. endosulfan, cypermethrin, NSKE,

achook, nimbitor, combination of neem products and synthetic pesticides tested

against Earias spp. on okra at Pune (Maharashtra), cypermethrin (0.01%) was

the most effective, recording the lowest fruit infestation (6.57 %), and was

significantly superior over other treatments. This was followed by endosulfan

(0.06%) which recorded 12.52 per cent fruit infestation compared to 44.16 per

cent infestation in untreated check (Ambekar et al., 2000b).

Gowri et al. (2002) noticed that endosulfan (0.07%) was most

effective in managing E. vittella and gave higher yield of okra at Bapatla (Andhra

Pradesh). In field trials at Brahmavar (Karnataka), Manjanaik et al. (2002)

observed that endosulfan (0.05%) gave the lowest fruit damage (2.92%) of okra

as well as highest fruit yield (61.85 qha-1) and benefit-cost ratio (1:9.26). Mishra

et al. (2002) found that significantly better management of E. vittella on okra

was acquired with the application of cypermethrin (100g), profenofos (500g ha-1)

and rocket i.e. combination product of profenofos and cypermethrin (440g a.i.

ha-1) at Bhubneshwar, Orissa.

42

Four sprays of cypermethrin 25 EC (0.0075%) at an interval of 10 days

starting from flowering were found effective in reducing infestation of okra fruits

by E. vittella at Rahuri in Maharashtra (Patil et al., 2002). According to Gupta

and Mishra (2006) and Mandal et al. (2006a), monocrotophos gave only low to

moderate level of protection to okra crop against E. vittella in field experiments

conducted in Bihar.

2.4.2.3.3 Foliage / flower pests

Kakar and Dogra (1988) found cypermethrin (0.008%) and malathion

(0.05%) effective against M. pustulata on okra in Himachal Pradesh. Use of 0.05

per cent malathion, monocrotophos or primphos-methyl during the vegetative

stage of okra crop and 0.05 per cent malathion or dichlorvos during flowering

and fruiting stages provided adequate protection to the crop against Podogrica

spp. in Nigeria (Ahmed et al., 1998).

Studies on evaluation of some insecticides at Garampani (Uttar

Pradesh) for the management of Mylabris spp. on okra by Prasad and Dimri

(1998) revealed that decamethrin (0.025%) was quite efficacious against this

pest. Parh et al. (1999) observed that cypermethrin at 12.5 g a.i. ha-1 reduced

the population of Podogrica spp. substantially on treated okra plants than those

on untreated ones in Jos (Nigeria).

Mishra et al. (2002) found that significantly better reduction of S.

derogata population on okra was attained with the application of cypermethrin

(100g), profenofos (500g ha-1) and rocket i.e. combination product of profenofos

43

and cypermethrin (440g a.i. ha-1) at Bhubneshwar, Orissa. Deltamethrin provided

good protection to okra crop from Podogrica spp. and S. derogata in Nigeria and

gave higher yields than neem seed extracts (Anaso, 2003). Endosulfan (0.07%)

or malathion (0.05%) sprays have been reported to be effective against Mylabris

spp. on okra in Himachal Pradesh (Anonymous, 2005b).

2.4.3 Use of biocontrol agents

Of the safer pest management strategies, biological suppression is

considered as an effective, environmentally non-degrading, economically viable

and socially acceptable method of pest management (Singh, 2001). Among the

various biological control agents, Trichogramma egg parasitoids are being

utilized for managing several crop pests effectively. Trichogramma belongs to

family Trichgrammatidae of the super-family Chalcidoidea of the order

Hymenoptera. The sub-family Trichogramminae comprises 11 genera and 30

species (Kyrger, 1918). Out of 12 indigenous species of Trichogramma, only T.

chilonis has the distinction of being the highest produced and most utilized

biocontrol agent (Manjunath, 1991; Brar et al., 2000). T. chilonis releases at the

rate of 50,000 ha-1 during the active egg-laying period hold promise against a

number of lepidopteran insect-pests.

T. brasiliensis Ashm. was observed to parasitize eggs of E. vittella

and H. armigera to the extent of 64 and 70 per cent, respectively, under

laboratory conditions but when released under field conditions at Parbhani

(Maharashtra) proved less efficient (Rao et. al., 1978).

44

Raja et al. (1998) reported from Tamil Nadu that the parasitoid, T.

chilonis decreased E. vittella damage on okra crop compared to untreated check.

In Egypt, effective management of A. gossypii (99.5% reduction) was achieved

by liberating coccinellid beetles (Coccinella 11-punctata) in the predator-prey

ratio of 1:200 at the beginning of detection of aphid population on okra (Al Eryan

et al., 2001). Sumathi and Balasubramaniam (2002) reported the efficacy of T.

chilonis release at Coimbatore (Tamil Nadu) against E. vittella and E. insulana on

okra crop in the order: T. chilonis (50000 ha-1 at 10 % fruit damage)> T. chilonis

(7.5 % fruit damage)> T. chilonis (5.0 % fruit damage)> T. chilonis (2.5 % fruit

damage).

Kumar et al. (2004) evaluated Trichogrammatids for the management

of fruit borer, H. armigera on tomato at Ludhiana, Punjab. They concluded that

lowest fruit damage (8.01%) was observed in the plots where T. chilonis was

released at the rate of one lakh ha-1, followed by T. chilonis at the rate of 75,000

ha-1 (9.20%), T. brasiliensis at the rate of 1 lakh ha-1 (11.66%) and T.

pretiosum at the rate of 1,000,00 and 75,000 ha-1 (10.88 and 11.82 %,

respectively). Further, higher yields were obtained at higher release rates.

2.4.4 Combination of treatments (IPM)

Integrated pest management appears to be the only viable option to

manage future insect-pest problems as part of a holistic crop production

technology. It combines care and concern for natural resources and the use of

modern methods to produce safer and wholesome food. This system represents

45

a logical way forward between the extremes of ultra intensive agro-ecosystems

and low output organic farming (Dhaliwal and Arora, 2003). Integration of

different pest management components in which natural enemies play an

important role, have proved effective, economical and ecologically sound

(Gahukar, 1997).

Endosulfan (0.035%) in combination with neem oil (0.3 %) proved

effective against fruit borer, E. vittella on okra and also produced higher yield of

healthy fruits at Padappai, Tamil Nadu (Samuthiravelu and David, 1991). Mathur

et al. (1998) noticed at Bangalore (Karnataka) that the combined application of

monocrotophos 36 SL (1 l ha-1) followed by 2 sprays of B. thuringiensis sub sp.

kurstaki (Dipel 8L, 1 l ha-1) + methomyl 40 SP (0.625 kgha-1) produced the

lowest okra fruit damage by Earias spp. (4.21%) and highest fruit yield (4.07 t

ha-1).

The combinations of dipel + endosulfan (0.1% + 0.035%) and dipel +

fenvalerate (0.1% + 0.0025%) considerably lowered okra shoot and fruit

infestation by E. vittella over untreated check at Bilaspur (Madhya Pradesh)

(Tomar, 1998). It was observed by Praveen and Dhandapani (2001) in field

experiments on okra at Coimbatore (Tamil Nadu) that 3 releases of predator, C.

carnea (25,000 larvae ha-1 release-1) + econeem 0.3 per cent (0.5l ha-1) at 15

days interval were effective in reducing the population of A. biguttula biguttula,

B. tabaci , A. gossypii, H. armigera and E. vittella on okra. Moreover, the fruit

yield (10326 kg ha-1) and cost: benefit ratio (1:2.60) were also higher when C.

carnea and Econeem were integrated as compared to the individual treatments.

46

Kaur (2002) reported from Ludhiana (Punjab) that leaf injury of okra

due to jassid infestation was lowest with seed treatment of imidacloprid (5g kg-1)

+ foliar sprays with monocrotophos (500g a.i ha-1) + cypermethrin(15g a.i. ha-1).

At Udayagiri (Orissa), lowest fruit borer incidence due to E. vittella (8.6% on wt.

basis) was detected when biotex (Bt sub sp. thuringiensis serotype) at 1 kg ha-1

was applied to okra crop twice and alternated with 1 malathion application at 0.5

kg a.i.ha-1 (Mishra and Mishra, 2002). These workers also reported that

mutineem (neem oil) at 2.5 l ha-1 or neemax (NSKE) at 1.0 kg ha-1 combined

with malathion application (0.5 kg a.i.ha-1) lowered the fruit borer incidence

(11.7-13.3 %), compared to the untreated check (16.9%). In addition, they

revealed that the aphid population remained very low (50.7/ top 3 leaves) in

treatment where biotox, neemax and mutineem were applied once in succession,

which was statistically at par with treatment where mutineem was applied in

between 2 malathion applications.

The combination treatment NSKE (2%) + cypermethrin (0.0075%)

effectively managed infestation by fruit borers on okra at Ahmednagar,

Maharashtra (Patil et al., 2002). Sprays of NSKE in combination with methanolic

extracts of sweet flag (Acorus calamus L.) and pungum (Pongamia glabra Vent)

at the rate of 0.42 per cent recorded highest mortality of leafhoppers on okra

compared to NSKE alone at Madurai in Tamil Nadu (Rao and Rajendran, 2002).

Sahoo and Pal (2003) revealed that 2 carbofuran sprays alternated with

azadirachtin spray lowered considerably the fruit damage by E. vittella on okra at

Mohanpur (West Bengal).

47

Application of endosulfan (0.07%) followed by Achook (0.7%) and

NSKE (3%) were effective in managing okra jassid at Faizabad, Uttar Pradesh

(Singh and Kumar, 2003). Balakrishnan et al. (2004) in field trials on rainfed

okra crop at Coimbatore (Tamil Nadu) indicated that 2 releases of T. chilonis

(1,00,000 ha-1; 40 and 60 days after sowing) with 2 sprays of Btk (1 kg ha-1; 90

and 120 days after sowing) recorded less mean larval population (0.33/ plant) of

H. armigera and higher yield (782 kg ha-1) as compared to combination

treatments of T. chilonis with other microbial insecticides viz. Ha NPV and B.

bassiana.

Satpathy et al. (2004) investigated at Varanasi (Uttar Pradesh) that

seed treatment of okra with imidacloprid at 3 g kg-1 and subsequent application

of monocrotophos at 500g a.i. ha-1 at 55 and 70 DAS offered maximum

protection against A. biguttula biguttula (0.53 nymphs/ plant) throughout the

growth period of crop.

Endosulfan (0.25 kg a.i. ha-1) and spicturin(Btk 0.5 L ha-1) alternately

sprayed between 6 am and 4 pm when the infestation by E. vittella exceeded

ETL (5.3% wt. basis) i.e. after 92 days of carbofuran (3G) soil treatment were

found most effective in lowering pest incidence and giving highest okra fruit yield

(Gupta and Mishra, 2006). In field experiments conducted at Samastipur (Bihar),

the treatment combinations of B. thuringiensis (500g ha-1) with lower doses of

endosulfan 35 EC (250g ha-1) and acephtae 75 SP (300g ha-1) recorded minimum

jassid population as well as larval population of E. vittella on okra (Mandal et al.,

48

2006a). Soil application of neem cake (@ 200kg ha-1) combined with sprays of

endosulfan 35 EC (@ 0.5 kg ha-1) or chlorpyriphos 20 EC (@ 0.5 kg ha-1) were

quite effective in reducing the incidence of jassid and shoot and fruit borer on

okra at Samastipur, Bihar (Mandal et al., 2006c).