eChapters

Chilli thrips: Scirtothrips dorsalis, Thrips palmi: Thripidae

The adults of this insect are small brownish black with fringed wings. The nymphs are slender and yellowish straw coloured, later acquiring more brownish hue. They lacerate the tissues and feed on the exuding sap. Leaves become crinkled, curled upward and shed. The attack can be confused with chilli mosaic symptom.  In capsicum and chilli, they also feed beneath calyx of flowers and fruits causing flower/fruit drop and reduction in yield and market value of capsicum. Buds become brittle and drop down. Plants get stunted and bronzed. The fruits if at all formed are crinkled and small.

Diamond back moth: Plutella xylostella: Plutellidae
 
The adults of this moth are small, greyish brown having pale whitish narrow wings and with inner margins yellow. There are three pale whitish triangular markings on hind margins of each forewing. At rest, when both forewings come together, they form a dorsal median patch of three diamond shaped yellowish white spots that give them their name diamond back moth. Hind wings have a fringe of long hairs.

Shoot and fruit borer: Leucinodes orbonalis: Pyraustidae

The pest is active throughout year, but more during monsoon period. Heavy losses up to 60% can occur.

The adult is a greyish brown medium sized moth with white and hyaline wings, having triangular brown and red markings on forewing. A crescent shaped mark facing outside at the apical margin is typical for the species. About 150-250 creamy white eggs are laid singly on leaves, tender shoots, flowers and developing fruits. Egg period is 3-5 days and the hatched larva completes its life in 15 days with 5 instars.

Shoot and fruit borer: Earias vitella (=E.fabia), E. insulana: Noctuidae

This is a pest on cotton, bhendi, hibiscus, holly hock and other malvaceous vegetables. The damage is due to the larva that bores into tender terminal shoots in the vegetative stage and flower buds;  flowers and young fruits in the fruit formation stage.  The damaged shoot drops, wither and dry up.  The infested fruits have bore holes, are deformed and become unfit for consumption.  Bore holes are plugged with excreta.

Amaranthus stem weevil: Hypolixus truncatulus :Curculionidae
 
It is an important pest of amaranthus and is widely distributed in India. It attacks both wild and cultivated amaranthus, especially the leafy varieties with large leaves. Hence, management involves destruction of unwanted, weedy wild amaranthus plants, to reduce the breeding place for the weevil. Adults are ash-grey in colour, with elbowed antennae and brown elytra. Females lay eggs singly in holes made on the stem, branches, petioles or midribs. Eggs are smooth, oval and pale yellow in colour. Incubation period is 3 to 8 days.

Sweet potato weevil: Cylas formicarius: Apionidae

It is a specific pest of sweet potato and the most important one. Adult weevils are ant-like, slender bodied having elongated snout-like bluish-brown head with geniculate antenna, bright red thorax and leg tips and bluish-brown elytra. Females make small cavities on the tubers or stems and lay eggs singly. Each female lays 180-200 eggs. Grubs are elongate, legless, pale-yellowish white in colour with smaller brown head. Pupation takes place in larval tunnels in the tuber. Incubation, grub and pupal stages last for 5 to 8, 14 to 17 and 4 to 5 days respectively. Life cycle is completed in 4-5 weeks and adults live for 95-110 days. The grubs bore into stems, tunnel inside and feed on soft tissues. Grubs and adults bore into tubers both in field and storage godowns. Affected tubers develop dark patches, which later start rotting. Feeding holes and adult emergence holes can be seen on vines and tubers.  In severe infestation the collar region of the plants shows unusual thickening due to proliferation and hypertrophy of tissues causing a characteristic terpenoid odour.  Even the slightly damaged tubers are unsuitable for cooking and consumption.  Hence yield loss in practice may come to 100% in many cases.

Aphids: Myzus persicae, Lipaphis erysimi and Brevicoryne brassicae Aphididae
 
Aphids suck the sap from potato foliage, causing wrinkling, cupping and downward curling of young leaves. The older leaves will become yellow, wilt and fall off.  They also excrete honeydew on which sooty mould develops covering affected parts with a thin superficial black coating that hinders photosynthetic activity of leaves resulting in stunted growth of plants. In addition, they also act as vectors, for transmitting potato leaf roll virus. Major damage by M.persicae and A. gossypii is through transmission of potato leaf roll virus.

Leaf-and shoot folders: Hymenia recurvalis : Pyraustidae

Pycnarmon cribrata;Phostria piasusalis

Cassava scale : Aonidomytilus albus: Diaspididae

White elongated scales appear in colonies on stems. Plants die in the field and under storage.  Stem becomes weak and dry, causing side branching to give bushy appearance.  Viability of planting material is reduced, resulting in poor establishment.

Aphids: Aphis gossypii :Aphididae

The aphids congregate on growing points and suck the sap. Honey dew secreted by the aphids can cause sooty mould in severe infestation. Attack leads to yellowish speckling and curling of leaves.
 
Thrips: Caliothrips indicus: Thripidae

Characteristic silvery white specks with black dots which are mostly faecal pellets, develop on leaves. Consequently, the leaves dry up.

Pollu beetle: Longitarsus nigripennis:Chrysomelidae

This pest is monophagous to pepper and no alternate host has been reported so far.

Nature of Damage

Adult is a shining blue flea beetle with yellow head and thorax and has thick enlarged femur and tibia. The adult beetle is only the size of a pin head.  The infested berries dry up and turn dark in colour. Berries become hollow and crumble when pressed and such hollow berries are called “Pollu” meaning empty. The eggs are laid on the berries @ 1-2 eggs in each hole. Eggs hatch in 5-8 days. The grub period extends for 30-32 days. The emerging grubs feed on the berries of pepper and consume the internal contents.

Thrips: Thrips tabaci: Thripidae

The nymphs and adults of the thrips desap from the narrow spaces between the inner leaf axils. Leaves are faded, with curled tips and shining silver streaks or brown spots.  Many minute yellow or white insects are seen moving, generally near the base or middle of leaves and they suck the sap from the plants.  Plants are faded and the yield is reduced.

Scale insects:Pseudaulacaspis cockerelli, Parasaisettia nigra:Coccidae

Attack Adults and nymphs feed on plant sap and cause wilting and drying of seedlings and young plants.
 
Brown soft scale: Lecanium sp. (=Coccus) hesperidum : Coccidae

Grasshoppers: Mecopoda elongata :Tettigonidae; Oxya velox: Acrididae

These pests occur both in nurseries and plantations. Both adults and nymphs feed on leaves by scrapping and eating outer tissues and margins. The emerging leaves are nibbled and the spot holes appear when the leaf unfurls. In severe conditions the entire leaf is eaten leaving behind only the midrib.

Shoot borer: Conogethes punctiferalis: Pyraustidae

The main damage done by the caterpillar of this pest is to bore holes in the pseudostem and to plug it with excreta, causing dead hearts. Larva is pale greenish with pinkish tinge and dark head and has fine hairs on the body with a pro thoracic shield. Adult is a medium sized moth, pale yellowish with small black spots on the fore and hind wings.

Management involves spraying dimethoate or malathion 1.5 ml/lit or phosphamidon 0.75 ml/lit of water. This is mainly intended to manage the adults flying in the crop canopy and the first instar caterpillars that are seen on the outside of the plants and before thsy enter the pseudostem. The spray has to be given at the very first spotting of dead haearts.

Coriander aphid: Hyadaphis coriandri: Aphididae

Coriander aphids are yellow-green in color, dusted with grayish wax. They have short, dusky, slightly swollen, siphunculi (or cornicles). The Aphids form dense, damaging colonies on leaves, heads, and stems of their host plants.

In its native land, Florida, USA, the life cycle of the coriander aphid is similar to that of other host-alternating aphids. Overwintering eggs occur on other hosts.  A fundatrix (or stem mother) hatches from the egg in the spring. Her offspring are parthenogenetic, and the winged-females are spring migrants. They colonize summer host plants in the family Umbelliferae.

Stem-borer: Sahyadrassus malabaricus: Hepialidae

Presence of the pest is understood when chewed tissue is seen at at the col­lar region. The mouth of the tunnel in which the borer feeds show pieces of bark, wood and frass particles held together by silk. The saplings break off at the point of injury. When the main stem is attacked, there is mat-like frass at basal region of stem. Larvae girdle main stem and bores downward killing the tree.

Adult moth is peculiar and hangs vertically down by the support of two pairs of legs. Egg period is for 7-10 days, and larvae live for about 10 months inside the larval tunnels. They pupate for 3-5 weeks.

Cinnamon butterfly: Chilasa clytia clytia : Papilionidae

Larvae defoliate plants. The larvae are pests on many crop plants and weeds and are common in the plains. The larvae are jet black at hatching. They develop a series of broad white patches. The adult is a common butterfly rich velvety brown, and spotted with white dots. The hind wings have arrow shaped streaks and crescent shaped spots.

Cardamom thrips: Sciothrips cardamomi: Thripidae

Thysanoptera

This thrips attacks other crops like amomum,  tea, colocasia, grapevine, castor, cotton, ginger and turmeric also. The thrips are minute greyish brown insects with fringed wings. They breed on unopened leaves, spindles, leaf sheath, flower bracts and floral tubes .

Scale insect: Lepidosaphes sp.: Diaspididae

The mature scale is elongated and oval in shape and dark grey in colour. They infest the stems, leaves and petioles, causing shriveled leaves due to sucking of the sap. The affected parts wither and dry up. In severe infestation leaves dry up and give sticky look and gradually the vine wilts.