Pests of Beans

Jassids

Amrasca biguttula biguttula Ishida
Family: - Jassidae
Order : -Homoptrera

• Economic importance

The adults are greenish yellow tilth front wings having a black spot on each, at the apical margin and two black spots on the vertex of the head. The nymphs are also green. They walk diagonally.

• Nature of damage

Both nymphs and adult suck the sap from the lower surface of the leaves. The damaged leaves curl upwards along the margins. Which may turn yellowish and show burnt patches. This affect adversely plants growth and yield.

• Life history

Whitish eggs are laid along leaf veins, which hatch about a week. Nymph moults 5 times and become adults within weeks. A generation is completed in a period of one month.

• Host plants

Cotton, bhendi and beans.

• Control measures

Spraying with 0.05% endosulfan, 0.03% Dimethoate or thiometon and 0.02% phosphamidon control the pest effectively.

Aphids

Myzus persicae Sulzer
Family: -Aphididae
Order: - Hemiptera

• Marks of Identification

Aphids are tiny yellowish soft-bodied insects, the adult is along 1mm long and has two projections called cornicles on the dorsal side of abdomen.

• Nature of damage

Aphids are found in large colonies on underside o leaves and tender shoots. The nymphs and adults suck the sap. Therefore, the affected leaves turn yellow, get wrinkled and destorted. The insect also exude honeydew on which fungus develops, rapidly covers the plant with sooty mould that interferes with the photosynthetic activity of the plant. As a result, the growth of plant is stunted and yield is affected adversely. Besides, they act as a vector for transmitting by aphds. The loss caused on this account is far more severe than by their feeding and devitalising the plant.

• Life history

Adults and apterous forms reproduce parthenogenitically. Single female produces 8-22 nymphs/day. The nymphs are completed in 7 to 9 days and several generations are completed in a season.

• Host plants

It is a polyphagous species have been recorded on beans, cabbage, brinjal, radish, chilly, tomato, tobacco, sanhemp, sweet potato etc.

• Control measures

Spraying with 0.05% endosulfan, 0.02% phosphamidon, 0.03% dimethoate, methyl demeton or thiometon control the pest effectively.

Thrips

Helicothrips indicus Bagnall
Family: -Thripidae
Order: - Thysanoptera

• Marks of Identification

The adults are minute, delicate insects, less than 1mm long and are light yellow in colour. Wings have fringe or hairs throughout and hence they are called fringed, winged insects. The nymphs are still smaller, minute and wingless.

• Nature of damage

The adults and nymphs feed on leaves. They scrape the epidermis and such the oozing sap. As a result, light brown patches appear on infested leaves. The affected leaves curl and become dry.

• Life history

A female lays about 30-50 eggs in leaf tissues, which hatch in 4-5 days. Nymphal stage lasts for about 10-15 days. A generation is completed in one month.

• Host plants

Beans, cauliflower, knolkhol, groundnut, ambadi, brinjal etc

• Control measures

Spraying with 0.05% endosulfan, 0.02% phosphamidon, 0.03% dimethoate, methyl demeton or thiometon control the pest effectively.

Mites

Hemitarsonemus latus Banks

• Marks of Identification

Mites are not insects as they have four pair of legs and belong to the class – Arachnida. They are extremely minute with variable colour.

• Nature of damage

They suck the cell sap from leaves. Badly attacked leaves show a peculiar bronzy and shiny appearance, ultimately wither and dry up.

• Host plants

Bean, chillies, cotton, cluster bean, brinjal, bhendi etc.

• Control measures

(1) Spray 0.2% sulphur or 0.03% dicofol (2) Sulphur dusting at the rate of 20-25 kg/ha also gives satisfactory control of the pest.

Pod borer

Helicoverpa armigera
Family: - Noctuidea
Order: - Lepidoptera

• Economic importance

Pod borer, aphids and pulse beetle are the important pests of this crop. Besides, cutworms and leaf eating caterpillars also damage this crop.

• Marks of Identification

The moths are light yellowish-brown about 25mm in length and 37mm in wing expanse. Forewings are pale brown with black. Hindwings are lighter in colour having smoky dark margins. Full-grown caterpillars are greenish with dark broken grey along the sides of body, measuring 31 to 50mm in length.

• Nature of damage

Caterpillars feed on tender foliage and young pods. They make holes in the pods and feed on developing seeds by inserting anterior half portion of their body inside the pods.

• Host plants

It is a polyphagous species gram, cotton, tomato, peas, beans, tobacco, ganja and sunflower are some of the important host plants.

• Life history

Shinning greenish yellow spherical eggs are laid singly on the tender parts of plants. They hatch in about 6-7 days. On hatching the caterpillars start feeding on tender leaves and shoots. After pod formation they bore into them and feed on developing grains. Larvae become full-grown in 14 to 15 days. Pupation takes place in earthen cocoons in soil near the plants. Pupal period lasts for about 1 to 4 weeks. A generation is completed in 4 weeks. The pest is active from November to March and hibernates in the pupal stage till next season.

• Control measures

In early stage of attack handpicking of the caterpillars and their destruction, help in reducing the intensity of infestation. Ploughing fields after the harvest of crop would expose the pupae, which would be destroyed by birds. The pest can be successfully controlled by spraying the crop with 0.05% quinalphos or fenitrohion. Spray with HaNPV @ 250 LE/ha.

Pulse beetle

Callosbruchus chinesis
Family: -Bruchidae
Order: - Coleoptera

• Economic importance

Though it is an important pest of pulses in storage, minor incidence is noticed in the field on pods from which the infestation is brought to the storage.

• Marks of identification

The adult beetle is more or less tapering at the anterior end; measuring about 6mm in length. There are two ivory coloured spots in the middle of the dorsal side of its body. The beetles are dark brown in colour. The grub is white, cylindrical, and fleshy and wrinkled with brownish month-parts. It is always found inside the grain.

• Nature of damage

It is a major pest of pulses in store. However, field infestation is also common. The young grubs burrow into the pod or grain and continue to develop inside the grain. The holes seen on pulses are the exit holes from where the adults have emerged. Such grains are unsuitable for sowing.

• Host plants

Mug, gram, tur, bean, masur, udid etc.

• Life history

The eggs are deposited mostly singly but sometimes in-groups on the surface of seeds and pods. In the fields, eggs are even laid on green pods, which carry infestation to the store. A female can lay from 60 to 95 eggs. Egg stage lasts for 4-5 days. On hatching, larva enters the grain and becomes full-grown in 2 to 3 weeks. Pupation takes place inside the grain. After 4 to 8 days the adults come out of the grain. It can fly and spread the infestation from store to the field. Adults live for 10 days or more.

• Control measures

It is difficult to control the pest in the field. In storage however, fumigation with carbon-di-sulphid at the rate of 1 lb/100 cu.ft. or 2.5 1b EDCT/100 cu.ft. or methyl bromide at 1 lb/1000cu.ft. would control the pest.