AN ASSIGNMENTON

Pests of Tomato

Course: Ag. Ento. 512 (PESTS OF HORTICULTURE CROPS)

Dinesh Dalvaniya M.Sc.(Agri.) , ENTOMOLOGY C.P.C.A S.D.A.U.

S.K. NAGAR

Pests of Tomato

1. Fruit borer: Helicoverpa armigera (Hub.) (Lepidoptera: Noctuidae)

Major host plants: Okara, Onion, Brinjal, Potato, Chillies, Cowpea, beans & several Cereals, Pulses & wild hosts.

Mark of Identification: The caterpillars are greenish to variable colours with dark broken gray lines along the side of the body.

They measures about 35-45 cm in length & the moth is brown with a V-shaped marking & dull black border on the hind wings.

Life cycle:

Female moth lays eggs on the leaves, flowers & developing fruits.

Eggs are yellowish & spherical.

A female lays an average of 750 eggs over a week’s time.

The younger larvae feed initially on the foliage for a while & later bore into the green fruits.

The larva while feeding, trusts its head into the fruit leaving the rest of its body outside.The fully matured larva pupates in a earthen cell.

H.armigera has a facultative pupal diapause which is induced by short day lengths (11-14 hours/day) & low temperatures (15-23 .c) experienced as a larva.

The total development period varies from 25-40 days depending upon the temperature & the host.

Damage:

Early instars feed on leaves & fruiting bodies.

Later they bore into fruits.

The bored fruits invite secondary infection by other organisms lead to rotting.

Natural enemies:

Bracon brevicornis. Campoletis chlorideae, Trichogramma chilonis,

Trichogrammatoidea sp. Are some of the important parasitoids recorded from India.

Management:

→Use of tolerant varities like Punjab Chuhara, Pant bahar, Azad, Pusa Hybrid-4

→Deep summer ploughing to expose the larvae & pupae to sunlight & predation by birds. →Planting of marigold (40 days old) as trap crop with every 16 rows of tomato (25 days old) attracts the pest. Collection & destruction of larvae from marigold flowers .

→Use of pheromone traps (5/ha) for early pest detection.

→Trichogramma brasiliense @2,50,000-Parasitised eggs/ha (Inundative release) during peak flowering stage.

→Spray HaNPV @ 250LE with jaggery (10/lit), soap powder (5g/lit) & a tinopal (1ml/lit) during evening hours or need based application of endosulfan @ 700 ai/ ha.

2. Defoliator: Spodoptera litura ( Lepidoptera: Noctuidae)

Major host plants: Brinjal, Cabbage, Cauliflower, Capsicum, Cucurbits, Okara, phaseolus, Potato, Sweet potato & Species of Vigna & other Wild hosts.

Mark of Identification:

The fully-grown larva is stout, cylindrical, pale-greenish brown with dark margins, which measure about 35-40 mm in length.

The moth is stout, dark with wavy white markings on the forewings & white hind wings.

Life cycle:

Commonly known as the tobacco caterpillar, S.litura, is one of the most important insect pests of agricultural crops in the Asian tropics.

The pest is active throughout the year.

Fecundity varies from 2000-2600 eggs, & oviposition days vary from 6 to 8 days.

The female moth after mating at night, lays abut 300eggs in clusters.

These clusters are covered with brown hairs.

The incubation period is about 3-5 days.

After hatching, the larvae feed gregariously together & later they spread ou & feed individually.

The larvae go through six instars.

The last instar larvae enter the soil for pupation.

The pupal period & the longevity of moths are 7-15 days & 7-10 days, respectively.

The total life cycle covers 32-60 days.

There are 8 generatyion in a year.

Damage:

The caterpillars feed on leaves in the nursery & in the main field & cause serious damage.

In crops like tomato & chillies, they bore into fruits & spoil them.

Larvae are very active at night.

Heavy infestation in the from of outbrakes can severely defoliate the crop.

Natural enemies:

Bracon brevicornis, Campoletis chlorideae & Eriborus argenteopilosus are the larval parasitoids, Trichogramma chilonis an egg parasitod, Bacillus thuringiensis (Bacteria), Beauveria bassiana, Metarhizium anisopliae, Nomuraea rileyi (Fungi) & Nucleopolyuhedrosis virus are some of the entomopathogens recorded.

Management:

Clean cultivayion to expose Spodoptera pupae to natural enemies.

Phrromone traps to predict Spodoptera egg laying

Had picking and mechanical destruction of caterpillars during early stage of attack helps in reducing the infestation.

Application of neem kernel extract during the early stage of crop growth.

Spray SINPV @ 250LE with jaggery (10g/lit) , soap powder (5g/lit) & a tinopal (1ml/lit) during evening hours.

Spray 400 ml malathion 50 EC or 370ml endosulfan 35EC in 250 litres of water per acre & repeat the spraying at 10 days interval, if necessary.

3. Serpentine leaf miner:

Liriomyza trifolii (Diptera: Agromyzidae)

Major host plants: Okara, Onion, Cucurbits, Beans, potato, Brinjal, Crucifers & Other crops.

Life Cycle:

Liriomyza trifolii is one of the polyphagus agromyzids causing serious damage on several crops including ornamentals.

Eggs are inserted just below the leaf surface.

Eggs hatch in 2-5 days according to temperature.

Many eggs may be laid on a single leaf.

Neonate larva is transparent later turn to a yellow-orange in later insatrs.

After hatching, the larva start mining into leaves.

The typical mine resembles a serpent shape, hence the name.

Pupation occurs in the soil beneath the plant.

Pupal development will vary according to season.

Adult emergence take place 7-15 days after pupation.

Life cycle completes in 12-15 days.

Damage:

Damage is due to mining into leaves & petiole by the larvae.

The photosynthetic ability of the plants is often greatly reduced as the chlorophyll containing cells are destroyed.

Severely infested leaves may dry & fall.

L. trifolii is also known to be a vector of many plant viruses.

Management:

Judicious nitrogen application reduces pest build up in endemic areas.

Infested leaves should be removed & destroyed.

Application of NSKE 4% with a sticker found to be effective.

Use of imidacloprid during early stages of crop growth before flowering.

4. Whiteflies: bemisia tabaci (Homoptera:Aleyrodidae)

Major host plants:

Okera,crucifers,cucurbits,solanaceous crops, pulses

Life cycle:

Eggs are laid in circular groups, on the undersides of leaves by a pedicel inserted into a fine slit made by the female,

Eggs are whitish in colour when laid later turn brown.

Each female lays up to 160 eggs.

Hatching occurs after 5-9 days at 30. C depending on host species, temperature and humidity.

On hatching, the first instar larva (only mobile stage) or crwler moves to a suitable feeding site on the lower leaf surface where it moults and becomes stationary throughout the remaining stages.

The first three larval stages last 2-4 days each (depending on temperature).

The fourth larval stage is called as puparium.

Pupation lasts for about 6 days.

The adult emerges through a t shaped rupture in the puparium.

A female may live up to 60 days while the male lives shorter(9 to 17 days).

There are 11 to 15 generations in a year.

Damage:

Apart from the damage to the crops by way of sucking the sap, B. tabaci is an important vector of a wide array of plant virus disease.

Eg. Tomato yellow leaf curl virus (TYLCV), Bean Golden Mosaic (BGMV), African cassava mosaic virus (ACMV) etc.

Infected plants exhibit any one or a combination of the symptoms like vein yellowing, inter-vein yellowing, leaf yellowing, blotching of leaves, yellow mosaic of leaves, leaf curling, vein thickening, leaf enations, leaf cupping, plant stunting.Natural enemies:

Encarsia brevivena, Eretmocerus corni, Eretmocerus mundus are some of the parasitoids, Chrysoperla carnea, Mallada boninensis, Coccinella septempunctata are the predators & Beauveria bassiana & Paecilomyces farinosus are the pathogens recorded from B. tabaci.

White flies damage

Management:

Many weed plants harbor whiteflies, Removal of weed hosts found to reduce both the incidence of whiteflies & associated viral diseases.

Seed treatment with imidacloprid @ 2.5g per kg of seed provides protection for 25-30 days.

Protection of seedling nursery by nylon net (200 mesh) covering for 25-30 days followed by need based application of systemic insecticides after transplanting.