Specific pests of brinjal, common in North-
Western regions of India.
Description
Adult
Adult damage on upper surface of leaf
The prothorax (area behind the head) of this grey and light
brown bug has a hood-like projection which extends out over the
body and comes to a point over the wings.
Adults (3 mm), straw coloured dorsally and dark brown to blackish
ventrally.
Pronotum and fore wings are reticulated consisting of irregular
thick lines forming a frame work of cells; and two pairs of lace-like
wings which are black at the base, coastal area hyaline with strong
spines on the outer margin; hind wings whitish and transparent
The bug has a dark head, pale yellow legs,
The body appears flattened and is about 4 mm long and 2 mm wide.
Egg
The 0.4-mm-long, oval-elongate egg appears almost bottle-shaped.
Female lays eggs singly in leaf tissues. Life cycle is completed in
15-30 days.
Greenish at the base and brown towards the tip, the egg has a crater-like
depression in one end with a white, lace-like border.
All eggs in each roughly circular clusters are deposited on end and
lean in different directions.
Nymph
Nymphs on the lower
surface of leaf
About 2 to 3 mm long, the mature nymph is yellow with a dark
spot at the tip of the abdomen. The body is covered with spines.
Nymphs are pale yellowish-brown with prominent spines.
Host Plants
The eggplant lace bug has a narrow host range.
Its food plants include tomato, potato, sunflower and cotton.
Damage
Severly infested plant
Circular discolored areas about the size of a quarter are the
first noticeable symptoms of lace bug damage.
The remains of an egg mass and a group of nymphs typically are
found on the underside of each discolored spot.
Lace bugs gradually move outward until the whole leaf yellows
and dries out.
Feeding in groups, they move from leaf to leaf and eventually to new
plants.
A severe lace bug infestation may kill whole plants or weaken them
to the point that fruit fails to develop.
Life History
They emerge and lay eggs in mid- to late May.
Each female spends 4 to 5 days depositing 100 to 200 eggs in a roughly
circular mass on the underside of a leaf.
The female guards her eggs against predators.
When the eggs hatch about 6 days later, the female continues to guard
her offspring. Nymphs feed and move as a colony, guided by the adult
female.
Molting every other day, nymphs develop through five instars and become
adults in about 10 days.
Several days may elapse before adults of the new generation mate and
deposit more eggs.
Approximately 6 annual generations occur on eggplant.
Control
Brinjal lace bugs are preyed upon by lady beetle larvae and adults,
spiders, and shield-shaped soldier bugs.
If the bugs appear in large numbers dust Endosulfan or Carbaryl 2g/liter
or spray Dichlorvos @ 1.5ml/liter of water.
About 13 mm long, this shiny, metallic green beetle has coppery brown
wing covers, which extend almost to the tip of the abdomen.
Two small tufts of white hairs occur just behind the wing covers on
each side of the body. Five more white patches are located on each side
of the abdomen.
Egg
White or cream colored egg is spherical and about 1.5 mm in diameter
when first laid in turf.
By the time it hatches, the egg has doubled its original size.
Larva
The grayish-white, slightly curled grub has a yellowish-brown head
and measures about 26 mm long when mature.
It can be distinguished from other white grubs by two rows of spines
which form a "V" on the underside of its last abdominal segment.
Pupa
The cream colored pupa, approximately 13 mm long and 6 mm wide, gradually
turns light brown and finally develops a metallic green cast.
Host Plants
Adult Japanese beetles infest over 275 different plants including
most vegetable crops.
Shade and fruit trees, ornamental shrubs, small fruits, garden crops,
weeds, and field crops often are damaged also.
The grubs are serious pests of lawns, other grasses, and nursery stock.
Damage
Gregarious in nature, Japanese beetle adults are often found feeding
in masses on flowers, foliage, or fruit of a few plants leaving others
nearby uninfested.
On most hosts, including okra, leaves are skeletonized and mature
fruit is damaged.
Injury to corn occurs when beetles feed heavily on the silks and ear
tips, sometimes reducing pollination and predisposing the ear to other
insect damage and fungal infections.
In localized spots, larvae injure the developing root systems of grass
crops or weeds.
Life History
The grubs overwinter in cells within 13 cm of the soil surface.
In spring they move upward, almost to ground level, where they complete
feeding and pupate.
The three larval instars complete development in about 140 days.
Adults emerge as early as mid-May
Throughout summer they attack the fruit and foliage of many plants
including silks of corn.
Soon after emerging females deposit 40 to 60 eggs in small batches
5 to 8 cm deep in the ground.
Under extremely dry conditions, many eggs and larvae perish.
However, during warm, set summers populations thrive and eggs hatch
about 2 weeks after deposition.
Newly emerged larvae feed until cold weather forces them into hibernation.
Only one generation occurs each year.
Control
Milky spore disease and several parasites often attack beetle grubs
and thereby keep Japanese beetle adult populations below economically
damaging levels.
Spray Carbaryl 3g/litre of water when infestation is severe.
Also attack bitter gourd, bottle gourd, potato and tomato.
Adults
Egg mass of leaf
feeding beetle
Adults are spherical, pale yellowish brown elytra mottled with
black spots.
A total of 28 spots are found on H. vigintioctopunctata while
E.dodecastigma has 12 spots.
Female lays as may as 120 to 180 eggs, Yellowish, elongated,
cigar-shaped eggs are laid in batches, generally on lower surface
of leaves, with their tips pointing which are in batches of 30
to 35 in number.
They hatch in 2 to 4 days and spiny, yellowish grubs start feeding
on the epidermis of leaves.
Grubs
Grub of leaf feeding beetle
Grubs are yellowish with spines all over body.
Pupation is on leaves, pupae are hemispherical.
Life cycle is completed in 25-50 days.
Symptoms
Scraping on leaf surface
Infested fruit
Infested leaves
Both grubs and adults feed by scraping chlorophyll from epidermal
layers of leaves, leaving the veins and veinlets, and cause characteristic
skeletonized patches on the leaves and forming ladder-like windows.
In severe cases even calyx of the fruit may also be infested.
Later, the affected areas on leaves dry and falloff and damage appears
in the form of holes in the leaves.
Control
Collect and destroy egg masses and skeletonised leaves with adults
and grubs.
If infestation is severe Endosulfan 2 ml/litre of water, Carbaryl
2g/litre of water or Dichlorvos 2ml/litre of water may be sprayed.
Hand picking of grubs and collection of beetles by handnets in the
early stages of attack is recommended for smallholdings.
The adult is wedge-shaped, about 2mm. Long and pale green in colour.
The forewings have a black spot on their posterior parts.
The nymphs are wingless, pale green in colour and are found in large
numbers on the lower surface of the leaves.
They have a characteristic way of walking diagonally in relation to
their body.
Nature of damage and host plants
The nymphs and adults pierce the plant tissues and suck the cell sap
by their mouthparts.
Initial damage is noticed curling up, followed by the yellowing of
the margins of leaves, while a continued excessive infestation may result
in etiolating of the leaves and subsequently stunted growth of plants.
A little-leaf, a virus disease is transmitted by E.devastans
from diseases to healthy eggplants.
Life History
Hopper nymph
Adult hopper
The adult female lays about 15 to 300 eggs in the leaf tissues and
the minute nymphs emerge out of the eggs in 4 to 11 days.
The nymphs moult five times.
The life cycle is completed in 14 to 30 days.
About 11 generation have been observed in a year, the duration of
each varying from 15 to 46 days, but there is considerable overlapping.
The insect is not known to hibernate and if the conditions are favorable
rapid multiplication takes place.
The adults are generally long-lived and can tide over during adverse
climatic conditions.
Control measures
Spraying of systemic insecticides like Monocrotophos or Phasphomidon
or Dimethoate @ of 2ml/litre of water is very effective. Repeat it 2
to 3 times at the interval of 10 days.
Spraying 0.3 percent malathion has given very satisfactory results
against adults and nymphs.
Apply recommended doses of Nitrogenous fertilizers.
The characteristic symptom is the small or little leaves.
The petioles are so short that the leaves appear to be sticking to
the stem.
Affected plants have narrow, soft, smooth and yellow leaves.
Newly formed leaves are much more shorter.
lnternodes of the stem are also shortened.
Axillary buds get enlarged but their petioles and leaves also remain
shortened giving the plant a bushy appearance.
Mostly there is no flowering but if flowers are formed they remain
green. Fruiting is rare.
The phytoplasma is transmitted by the Plant hopper Hishimonas
phycitis .
Control
Pusa Purple Round is tolerant to little leaf.
The severity of the disease can be reduced by destruction of affected
plants and spraying of insecticides like Methyl demeton 1 ml/litre or
Malathion 3 ml/litre of water.
Highly polyphagous and has a world-wide distribution.
Adults are ovate, reddish brown with four pairs of legs.
Eggs are globular and whitish.
Larvae (Ist instar nymphs) are pinkish with three pairs
of legs while nymphs (later instars) are greenish-red, look like
the larvae, but have four pairs of legs.
Life cycle is completed in about 20 days.
Symptoms
Silken web by red spider mite
Colonies of mites are found feeding on ventral surface of leaves
under protective cover of fine silken webs, resulting in yellow
spots on dorsal surface of leaves
Affected leaves gradually curl, get wrinkled and crumpled.
In heavy infestations even fruits are affected.
Control
Sulphur dust, or sprays of wettable sulphur 2g /litre, Ethion or Dicofol
@ 2ml/litre of water are recommended.