AGRICULTURE AND IRRIGATION

PESTS

A brief account of various pests of crops in the district is given in the following paragraphs. The extent of damage caused by them cannot be gauged accurately as it depends upon the severity of infestation in the year of attack. Remedial measures mentioned against different pests are such as are within the means of the average cultivator.

Of Paddy.— Paddy is generally affected by pests such as, stem-borer, swarming caterpillar, army worms, paddy gall fly, paddy grasshoppers and crab. The nature and extent of damage caused by these pests and their various control measures are given below: —

Stem-borer (Schoenobius incertellus, Wlk.).—Marks of identification: The caterpillar is one inch in length; yellowish white in colour and smooth with orange-yellow coloured head. Moths are straw-coloured with yellow fore wings having one black dot on each side while the hind wings are white. They are ½" to ¾" long with a wing expanse of 1½".

Nature of damage: The larvae bore into the stem of paddy plant causing death of central shoot. If the crop is attacked at later stage, the shoot bears empty ears locally known as 'Palinj'.

Life history.—Female moth lays eggs in masses on the tips of leaves. These hatch in about a week's time and the tiny larvae initially feed on the leaves for a day or two and then start boring into the stem. Larval period is about 4 to 5 weeks. Pupation takes place inside the stem in a silken cocoon. Pupal period is 8 to 10 days. Thus a generation is completed in about two months. The pest is carried over to next season by the hibernating larvae or pupae in stubbles remaining in field after harvest.

Control measures: The pest can be controlled by preventive measures only: as the same is an internal feeder. These include—

(1) Ploughing the land, collection and destruction of stubbles after the harvest of the crop.

(2) Removal and destruction of affected plants along with the caterpillars inside.

(3) Destruction of egg masses by clipping leaf tips at the time of transplanting.

Spraying with 0.04 per cent endrin (2 ml. endrin 20 per cent E.C. in 1 litre of water) or parathion (1 ml. parathion 50 per cent E.C. in 2 litres of water) or phosphamidon (1 ml. phosphamidon 100 per cent E.C. in 2.5 litres of water) has been reported to be effective in reducing the pest. Trials with lindana and carbaryl granules in paddy water are also reported to be effective.

Swarming caterpillar (Spodoptera mauritia B.): It is dark greenish in colour with a slight yellow tinge and dark white stripes along the body length and with dark head. When full-grown, it measures 1½" in length. Moths are stoutly built with dusky brown hind wings. The fore wings are dark brown with a black spot. They are ½" to ¾" in length with a wing expanse of 1 ¼".

Army worms (Cirphis unipuncta H.): These are dull, greenish in colour with broad light-coloured stripes running along the lateral sides of the body. Full-grown caterpillar is smooth, stout-bodied and measuring about 1" to 1¼" in length. Moths are of two types. The first one is brownish red with prominent spots on the anterior margin of the wings. Hind wings are pale coloured with dark borders. The other one is dusky brown with a dark median line and spots on the apical margin of wings

Nature of damage: Immediately after hatching the caterpillars feed on grasses or young paddy seedlings. When the pest attacks the crop at the time of grain formation, considerable losses are caused due to shedding of grains. The pest is active mostly during night while during day time larvae hide in whorls of leaves, leaf sheath or under clods, if the field is not flooded.

Host plants: Besides paddy, jowar and other cereal crops are also attacked by the pest.

Life history: Two to three hundred eggs covered with greyish hair are laid in masses mostly on the lower surface of leaves. Eggs hatch in 7 to 8 days. Caterpillars hatching out of eggs feed on the leaves mostly at night and become full-grown in about two weeks. Pupation takes place in soil in earthen cocoons. Life-cycle is completed in about 40 to 50 days. Larvae have migratory habit and they move like army from one field to another causing complete destruction and hence the name 'Army worm'. It has also been observed that initial good start of monsoon followed by the prolonged dry spell is favourable for the activity of the pests. More than one generation are found in a season.

Control measures: Preventive measures include protection of seed-beds by trenching around the seed-bed and collection of egg masses followed by their destruction, trapping the larvae under bunches of dry grass, flooding the field, etc. Ploughing the fields immediately after the harvest of the crop to expose hibernating pupae in soil also helps considerably in keeping the pest under check. Pest can also be effectively controlled by application of 5 per cent BHC dust at 20—25 lbs. per acre or 0.2 per cent BHC spray. The treatment should preferably be given in the evening when the pest is active.

Paddy gall fly (Pachydiplosis oryazae W.)—Marks of identification: The larva is a legless maggot while the adult is a fly having two simple wings and long slender legs. Adult female is reddish while the male is ash grey in colour. Wing expanse is about 1/15".

Nature of damage: Young larvae on hatching gets access into the growing bud and lacerates the tender tissues thereby checking the apical growth. Tubular structure called " Silver shoot" is formed in place of normal shoot. Infestation is highest during the tillering stage.

Life history: Eggs are laid on the basal side of leaf which hatch in 3 to 5 days. Larvae on hatching enter the growing bud. Larval period lasts for 8 to 10 days and pupation is within the silver shoot which lasts for three to five days. Thus generation is completed in 3 weeks time.

Host plants: Besides paddy, grasses and wild rice are host plants.

Control measures: Being an internal feeder it is difficult to control the pest. However, the following control measures have been found to minimise the pest incidence:—

(i) Clean up campaign to destroy other grasses which serve asalternate host plants.

(ii) Three sprayings with 0.04 per cent parathion (1 ml. parathion 50 per cent E.C. in 2 litres of water) or endrin (2 ml. endrin 20 per cent E.C. in 1 litre of water) at 15 days interval as soon as pest incidence is noticed. One spray in the nursery may be given if the infestation is observed.

Paddy Grasshoppers (Hieroglyphus banian, Fb.)—Marks of identification: Adults are medium sized greenish in colour without spots and with bluish hind tibia. There are 3 dark streaks on prothorax. Female measures about 1½" to 2" while the male measures 1" in length. Nymphs are brownish but turn greenish as they grow.

Nature of damage: Both nymphs and adults feed on foliage and also on developing ears.

Host plants: Besides paddy, the pest attacks sugarcane and grasses.

Life history: Eggs are laid in soil in batches of 30 to 40 especially along the bunds or in fallow lands. These eggs hatch immediately after the first shower of rains and tiny nymphs feed initially on grasses but later migrate to the main crop in fields. They become full-grown in about 70 to 80 days after moulting 4 to 5 times. There is only one generation in a year and carry over of pest is through egg masses.

Control measures : If the pest occurs regularly in a particular area, it is better to plough the fields and crush the egg masses by clod crushing. Scraping the bunds and destroying egg masses also help in keeping the pest under check. The insecticidal trials conducted had shown that the application of 5 per cent BHC dust at 20 to 25 lbs. per acre or 5 per cent BHC poison bait at 20 to 30 lbs. BHC per acre or spraying with 0.2 per cent BHC spray at 80 to 100 gallons per acre, is quite effective in controlling the pest.

Crab (Paratelphusa Jacquemontii)—Marks of identification: It is whitish to dark brown in colour with yellowish borders. Eyes are stalked and dark black at the back. The body measures 0.5 cm. in thickness and 4 cm. in length.

Nature of damage: Crabs are polyphagous. They cut the young paddy plants near the ground level and carry them to their burrows for feeding. They are mostly active during nights. Be sides this they prepare a series of burrows in the embankment of paddy fields as a result of which, water is not retained in the field which is virally required for the crop growth.

Control measures: Fumigation of crab burrows with cyanogas dust was recommended so far. However, poison baiting with 3 per cent DDT 1 per cent dieldrin or 0.08 per cent endrin baits in boiled rice or application of 0.05 per cent endrin or parathion at the rate of 80—100 ml. per burrow is quite effective in controlling the pest.

Of Jowar Jowar stem borer (Chilo zonellus swinh).—Marks of identification:The caterpillars are dirty white with many spots on the body and with a brown head. The full-grown caterpillar measures about ½" to ¼" in length. The moths are straw coloured with forewings pale yellowish grey having minute dots on the apical margin and white hind wings.

Host plants : Jowar, maize and grasses.

Nature of damage: Caterpillars bore inside the stems causing thereby drying of the central shoots called " Dead Hearts " due to which reddening of stems takes place.

Life history: Creamy white eggs are laid on leaves in clusters which hatch in six days. Young caterpillars bore into the stems and they remain there for three to four weeks, after which the full-grown caterpillars pupate in situ. The pupal period is 7 to 10 days and the total period of the life-cycle is 5 to 6 weeks. The pest hibernates as larvae in stubbles. The period of activity is from June to November. There are about four generations in a year. Summer jowar is frequently found heavily infested by this pest.

Control measures : Being an internal feeder only preventive and mechanical measures are found effective and economic: —

(i) The affected plants should be pulled out along with the caterpillars inside and destroyed promptly.

(ii) After harvest of the crop stubbles should be collected and burnt to destroy the hibernating larvae.

(iii) The fodder to be fed to cattle should be cut into small pieces and stored.

Jowar stem fly (Atherigona indica)—Marks of identification : Its maggots are legless, tapering anteriorly and are found feeding inside the stems of young plants. The adults are similar to house-flies but very much smaller in size, and on their dorsal side, there are a few dark spots.

Host plants: Jowar and other millets.

Nature of damage: The maggots bore inside the stem and cause dead hearts and are generally more common in a very young crop.

Life history: The eggs are laid on stems or tender seedlings and they hatch in 2 to 3 days. The maggots bore into the stems of young plants and feed inside the stem for about a week. Full-grown maggots pupate inside the infested stems of plants. The pupal period lasts about a week. The pest is occasionally serious in early stages of the crop.

Control measures: As the pest is an internal feeder, mechanical methods though laborious have been found to be more useful which consist of: (i) removing the affected seedlings and destructing the larvae, and (ii) increasing seed rate to make up the loss. For hybrid varieties which are more susceptible to the attack of the pest, the following chemical control measures have been recommended: —

(i) Soil application of 10 per cent phorate granules at the rate of 7 kg per acre prior to sowing. The granules should not come in close contact with the seeds, and (ii) if phorate is not available 4 sprays with 0.05 per cent endrin (2.5 ml. of endrin, 20 per cent E.C. in 1 litre of water) at 10 days interval starting from 7 days after germination.

Flea beetle (Chaetochnema indica)—Marks of identification : The beetles are black and small about 1/10" long, oblong and with the hind pair of legs thickened by means of which they are able to jump about. Some species may be brownish in colour.

Host plants: Jowar is some times seriously damaged in the eastern parts of Maharashtra, though the pest may also occur at other places. The species is also a serious pest of sann-hemp.

Nature of damage: The beetles feed generally on the middle part of the leaf-blade and not on the border as is the case with caterpillars and grasshoppers. When the flea beetle feeds on the leaf, there result numerous small holes on its surface.

Life history: Its life history is not known fully but the younger stages, i.e., the grubs, are supposed to be root feeders.

Control measures : Dusting 10 per cent BHC at the rate of 8—10 kg per acre gives satisfactory control of the pest. Treatment with 0.05 per cent endrin or 0.15 per cent malathion would also prove to be effective.

Army worms (Cirphis unipuncta)—Marks of identification: Full-grown caterpillars are 1" to 1½" long, smooth bodied and dull greenish coloured with broad light coloured strips running along its length on either side of the body. They are found in the central whorl of plants, or may remain under stubbles around the plants in soil. Moths are of two types. One type of moth is brownish red with prominent spots on the anterior margin of the wings. The hind wings are pale in the middle with dark borders. The other type of moth is dusky brown with a dark median line and less prominent spots on the apical margin of the wings. A pest called swarming caterpillar which is a little darker and with longitudinal bands is also known to infest jowar. Their habits and the control measures for them are identical.

Host plants : Jowar, maize, bajri, paddy and other cereals.

Nature of damage: The caterpillars feed on leaves mostly at night, while during the day they remain hidden in the whorl in the clods underground. They migrate from one field to another when their food is exhausted and hence the pest is called army worms.

Life history : Round, greenish white eggs are laid on central leaves in two parallel rows in batches which hatch in a week. Caterpillars feed on leaves from the margin inwards and hide in the central whorl of the plant. In bad cases of attack they completely defoliate the plants as they have a habit of feeding together. Their larval period is from 21 to 28 days. Full-grown caterpillars descend to the ground for pupation. Their pupal period lasts from 8 to 10 days. The total period of their life-cycle is five to six weeks. The pest is active from June to November. Kharif crops suffer more from it than rabi crops. There may be a number of generations during a season, after which the insects hibernate in the pupal stage in soil. The pest does not become abundant every year and it is observed that when a long dry spell follows a good start of monsoon, the pest assumes epidemic form. It shows a tendency to subside if heavy showers occur thereafter.

Control measures : (1) Collection of egg masses and their destruction, (2) if the attack is localised, caterpillars may be collected by employing labour and destroyed, (3) deep ploughing of the infested fields after the harvest of the crop to expose the hibernating pupae to the action of weathering agencies and birds, (4) dusting with 10 kg of 10 per cent BHC or spraying 0.2 per cent BHC [½ kg of 50 per cent BHC (WP) in 120 litres of water], (5) dusting with 5 per cent aldrin or 3 per cent heptachlor at the rate of 10 kg per acre also gives effective control of the pest.

Hoppers and Aphids (Peregrinus maidis, Ashm. and Rhopo-losiphum maidis, F. and Aphis sacchari Zhent): Delphacids (Peregrinus maidis, Ashm.) and Aphids are responsible for causing the sugary secretion on jowar, the symptoms are locally known as Chikta. It is quite severe especially on rabi jowar.

Marks of identification : Delphacids are wedge shaped, greenish brown in colour with blackish spots on wings.

Aphids: Adult is oblong and dark brown or yellowish green in colour having two projections called cornicles on the dorsal side of the abdomen. It is mostly found in the wingless stage.

Host plants : Sugarcane, maize and grasses.

Nature of damage : Sugary secretion is seen on the leaves of the plant and also in the whorl and ultimately the growing shoots of the plant are damaged and further growth is checked.

Control measures : The problem of ' Sugary disease' is still under investigation, however, spraying with 0.02 per cent diazin-on, thiometon, endrin or dusting with 5—10 per cent BHC dust helps in reducing the intensity of infestation of these pests.

Of Gram.— Gram pod borer (Heliothis armigera)—Marks of identification: The moths are stout, light yellowish brown, with a wing expanse of 3.7 cm. The forewings are pale brown with some black dots and the hind wings are lighter in colour with smoky dark margins. The caterpillars are greenish with darker broken grey lines along the sides of the body. They are 3.7 to 5 cm in length when full-grown.

Nature of damage: The caterpillars feed on tender foliage and young pods. They make holes in the pods and eat the developing seeds by inserting the anterior half portion of their body inside the pods.

Host plants: Gram, cotton, tomato, peas, tobacco, ganja, safflower, etc., are the principal hosts.

Life history : Shining greenish yellow eggs, spherical in shape are laid singly on the tender parts of plants and they hatch in about 6 or 7 days. On hatching the caterpillars start feeding on tender leaves and shoots and as they grow, they bore into the pods and eat the developing grains inside. They become full-grown in 14 to 15 days and descend to the ground and pupate in earthen cocoons in the soil near the plants. Their pupal period lasts from one week to a month. The pest is active from November to March.

Control measures : Hand picking of the caterpillars during initial stages of attack would help in reducing the future infestation. Ploughing the field after the harvest of crop would destroy the pupae.

The pest can be effectively controlled by spraying the crop with 0.1 per cent carbaryl or 0.06 per cent isobenzan or 0.2 per cent DDT or 0.03 per cent aldrin or endrin or heptachlor or 0.12 per cent phosphamidon at the rate of 250 litres per acre.

Of Tur.— Tur pod caterpillar (Exelastis atomost)—Marks of identification: The moths are slender, not more than 12 mm long and are grey with long, narrow wings. The front wings are divided into two parts and the hind wings are cut into three parts and provided with a fringe-like border. The full-grown caterpillars are about 12 mm long, greenish brown in colour and are fringed with short hair and spines.

Nature of damage: The caterpillars bore into green pods and feed on the developing seeds.

Host plants : Tur and Wal.

Life history : Minute eggs are laid singly on the tender shoots, leaves, flowers or pods and they hatch in about 5 days. On hatching, the caterpillars first scraps the surface of pods and gradually cut holes and thrust their heads into pods and feed on seeds and become full-grown in about four weeks' time. They pupate on the pod surface or even in the burrows of infested pods. Their pupal period lasts for two weeks. The pupae are also fringed with short hair and spines and are often liable to be mistaken for larvae. The total period of their life-cycle is about seven weeks.

Control measures: Preventive measures include collection of the infested pods and their destruction during early stages of attack and avoiding leguminous crops consequently in the same field.

Spraying the crop with 0.2 per cent DDT at 250 litres per acre or dusting with 1 per cent telodrin or 1 per cent endrin or 5 per cent BHC or 3 per cent heptachor or 10 per cent carbaryl or 4 per cent malathion or 1.5 per cent dieldrin or 5 per cent DDT or 3 per cent morphothion or 2 per cent parathion at 9 kg per acre have also proved effective.

Tur pod fly—(Agromyza obtusa)—Marks of identification: Freshly laid egg is white, broad and rounded at the posterior and narrowed anteriorly into a curved elongated hollow process. It measures 0.66 x 0.15 mm. Newly hatched larvae is white with dark brown mouthparts. It measures 0.61 x 0.12 mm. A fine brownish stripe runs along the entire mid-dorsal line of body. Full-grown larvae is creamy white measuring 3.5 to 4 mm in length and 1.25 to 1.5 mm in breadth. Pupae measure 2.5 mm x 1.25 mm. Adult flies are glossy black with pubescent eyes and strong legs with femur slightly thickened. They are proboscis brown at the apex, wings clear, veins brown, yellowish at their bases, halteres black, abdomen broadly ovate. They measure 2.75 mm in length.

Nature of damage: The pest is widely distributed throughout India. Young larvae after hatching from the eggs enter soft seeds and feed on them. At first, the damage resembles that of leaf miners as their galleries run just under the epidermis of seed. Later they burrow deep down resulting in decaying of the grains which become unfit for either consumption or germination. As high as 80 per cent of the pods and 63 per cent of the grains may be damaged. In advance cases of damage, the pods present a twisted appearance.

Host plants: Few hosts belonging to family leguminosae have been recorded.

Life hitory: Copulation starts within 24 hours after emergence and egg laying takes place soon after. Life of adult is short and oviposition is limited to 3 to 4 days. A female lays on an average 38 eggs with a maximum of 79. It avoids very young as well as mature pods of oviposition. It pierces her ovipositor in pericarp and deposits a single egg. When a pod is opened the eggs appear like needles projecting from the wall of the pod. Larval period is about 6 days at 26° C but during winter it may be as much as 21 days. Pupal stage lasts for 8 days at 27°C and for 30 days at 18°C. Thus it requires about 22 to 23 days to complete one generation.

Control measures : Removal of affected pods of first brood during winter will help in reducing the population to a great extent. The crop may be treated with 0.2 per cent DDT or 0.02 per cent endrin spray at the rate of 300 litres per acre to kill the adult flies.

Tur Pod Bug (Clavigralla Gibbosa)—Marks of identification: The adult bugs are about 12 mm long, are greenish brown in colour, have a spined pronotum and a femur swollen at the apical end.

Nature of damage: Both the nymphs and adults suck the sap from pods and cause the infested pods to shrivel. The pest, however, is rarely serious.

Host plants: Tur, Wal, etc.

Life history : The eggs are laid in rows. On hatching, the nymphs start sucking the juice from pods and pass through five moults to reach the adult stage.

Control measures: Preventive measures are the same as those in the case of the pod caterpillar, 5 per cent BHC powder, if dusted at the rate of 8 kg per acre may control the pest.

Of Potato.— Potato Tuber moth (Gnorimoschema operculella)— Marks of identification : Full-grown caterpillars are 18 mm. long, pinkish white or greenish with a dark brown head. The moths are very small, narrow-winged, measure 12 mm from tip to tip of the wing and are greyish brown in colour, mettled with hue of a darker brown.

Nature of damage: In the early stages of the crop, the pest injures the plant as a leaf-miner, but this injury seldom attracts much attention. The infested tubers rot. The activity of the pest in stored potatoes can be generally made out by the presence of black excreta near the eye buds. On cutting open one of such potatoes, one finds the caterpillar in the pulp.

Host plants : Potato, tobacco, tomato, egg-plant and weeds of the same family.

Life history: The eggs are laid singly on the underside of leaves or on exposed tubers. On hatching, the caterpillars produce blotch mines on the leaves and subsequently bore into the stems and become full-grown in 2 to 3 weeks. Full-fed caterpillars pupate in a greyish, silken dirt-covered cocoon, about 12 mm in length and entangled in dried leaves or in trash lying on the ground. The pupal period lasts for 7 to 10 days. The total period of their life-cycle is about 4 weeks in warm weather. Warm weather is most favourable for the spread of this pest and there are several generations in a year. The later generations infest the tubers in the field and come out of them for pupation.

Control measures: Timely earthing up of the crop to cover the exposed tubers helps in reducing the intensity of infestation. Initial field infestation can be checked by dusting the crop with 5 per cent DDT or 0.65 per cent lindane at the rate of 8 kg per acre or spraying with 0.03 per cent lindane or 0.2 per cent DDT. Heaps of harvested potatoes should not be kept exposed in the field but covered with straw. The infested tubers should not be rejected before storage.

Fumigate the tubers with carbon-di-sulphide at the rate of 1 kg per 27 cm for 48 hours at 70° F or methyl bromide at the rate of 1.1 kg per 27 cm for atleast 3 hours before storage. Carbon-di-sulphide is reported to induce sprouting in storage. Bags used for storing potatoes may be treated with 1 per cent DDT solution in xylene. Walls of godowns should be sprayed with 1.5 per cent DDT at the interval of 3 months. Treatment of tubers with 0.65 per cent lindane or 5 per cent DDT or malathion at the rate of 125 to 250 gm per 100 kg is also reported to offer good protection against the pest. Such treated potatoes however should not be used for consumption. If cold storage facilities are available, the produce can be safely stored for a longer period.

Cutworm.— (Agrotis ypsilon Rott.)—Marks of identification : Full-grown caterpillars are about 18 mm long, dirty black in colour and have habit of coiling up at the slightest touch. As they become old, they live in cracks of soil nearabout the base of plant during the day time and feed on young plants at night. The moths are about 25 mm long with dark or blackish grey patches on their forewings and are attracted by light.

Nature of damage: The caterpillars are active during the night. They cut the young plants at the ground level and feed on tender leaves and shoots. They cut many more plants than they can eat.

Host plants: Potato, tobacco, peas, gram, cotton, tomato, lucerne, chillis, brinjal and other vegetables.

Life history: Creamy white spherical eggs are laid singly quite near one another on the lower surface of leaves and stems close to the ground. The egg-laying capacity of a single female is about 300 eggs. The eggs hatch in a period of 4 to 7 days. Newly hatched caterpillars are light-grey coloured and move as a semi-looper. The caterpillars become full-grown in about 3 to 5 weeks' time and pupate in the soil in earthen cocoons. The pupal period is 11 to 18 days. The total period of their life-cycle in cold weather in the plains is about 5 to 9 weeks and there are generally two generations in a year.

Control measures: Clean cultivation by regular interculturing should be practised. Heaps of green grass may be kept at suitable intervals in the infested field during evening to trap the caterpillars. These heaps should be removed along with the caterpillars during early morning and destroyed. Irrigation also brings the caterpillars to the surface and then birds destroy them. The pest can be effectively controlled by 5 per cent BHC or paris green in 25 parts of wheat bran or one part of 50 per cent wettable BHC in 9 parts of wheat bran. Little jaggery or molasses is added for taste. Sufficient quantity of water should be added to moisten the bait. Bait should be broadcasted in the field in the evening at the rate of 10 to 25 kg per acre depending upon intensity of infestation. Poison baits though reported to be effective are rarely used as it involves high cost. Soil application of heptachlor or aldrin or DDT at the rate of 1 kg of active ingredient per acre before planting is also reported to reduce the pest infestation.

Mites (Hemitarsonemus latus, Banke)—Marks of identification: They are extremely minute with variable colour.

Nature of Damage: They suck the sap from leaves. Badly attacked leaves show a peculiar bronzy and shiny appearance and ultimately wither and dry up.

Host plants: Potato, citrus, cotton, jowar, etc.

Life history : The eggs are laid on the leaf surface from which young-ones hatch out, feed on the host plants and grow into wingless adults. Some plant-feeding mites cause galls on the leaves and others cause reddening or browning, as on jowar; silvering and bronzing are observed on guava, cotton, citrus, etc.

Control measures: The crop should be sprayed with lime sulphur wash after diluting with 90 parts of water. Sulphur dusting at the rate of 8 kg per acre also gives satisfactory control of the pest.

Of Brinjal.— Brinjal shoot and fruit borer (Leucinodus arbona-lis G.)—Marks of identification: The moths are medium sized and have whitish wings with large brown patches all over. The head and thorax are blackish brown. The caterpillars are pale white about 12 mm long when full-grown.

Nature of damage: The caterpillars bore into the stem and riddle it and eat the internal tissues and thus cause the plants to wither. When the infestation is on shoots, they bend down and wither. They attack the fruits as well, making their entry under the calyx when they are young, leaving no visible signs of infestation. The large holes seen on fruits are usually the exit holes of the caterpillars.

Host plants: Brinjal and stems of potato.

Life history: Flat whitish eggs are laid scattered on the leaf surface which hatch in 3 to 5 days. On hatching, the caterpillars start boring into the tender, growing shoots of plants and when fruits are formed they bore into them. They feed on the internal part of the shoots or fruits and become full-grown in 7 to 13 days. Full-grown caterpillars come out of the larval burrow and pupate in boat-shaped cocoons. Their pupal period lasts for 7 to 11 days.

Control measures: Removal and destruction of the affected fruits and shoots along with the caterpillars helps in reducing the intensity of infestation. Continuous cropping of brinjal and potato in the same area encourages the pest activity and hence proper rotation should be followed.

Two sprayings with 1 per cent DDT or 0.08 per cent endrin at 3 and 6 weeks after transplanting are reported to be promising against the pest.

Of Chillis.— Thrips (Atiaphothrips Dorsalis)—Marks of identification: The adults are minute delicate insects, less than 1 mm long and are light yellow in colour. Their wings are fringed with hair. The younger stages are still more minute but wingless.

Nature of damage: These insects have mouth parts suited for scraping the epidermis of leaves and sucking the oozing sap. The plant tissues damaged by insects initially become whitish but later turn brown and ultimately dry. As a result of feeding leaves curl and become small, such symptoms are locally known as Murda or Bokadya.

Host plants: It is a polyphagous species recorded on cotton, mango, tondli, bottlegourd, guava, bhendi, brinjal, onion, etc.

Life history: Adult female lays fertilized or unfertilized eggs inside the leaf tissues generally on the lower side of leaf. A female can lay 50 to 60 eggs at the rate of 4 to 6 per day. Average incubation, larval, prepupal and pupal periods have been observed to be 8 to 9, 4 to 6, 2 and 3 days, respectively. Prepupal and pupal stages are generally found in soil at a depth of 1" to 2". The pest is more active during later part of monsoon, especially during a dry spell.

Control measures: The pest can be effectively controlled by spraying with 0.2 per cent DDT. So also, 0.02 per cent endrin, telodrin, methyl demeton, diazinon, dieldrin, thiometon, endosulfan, isobenzan, phosphamidon or lebaycid or 0.05 per cent malathion or dimethoate, 0.1 per cent carbaryl have also been found to be quite promising. Addition of sulphur to chlorinated hydrocarbon insecticides in equal proportion would help in controlling mites also. Dusting with one per cent endrin plus sulphur or 10 per cent DDT sulphur at the rate 9 kg per acre is also equally effective. Repeated applications may be given at 15 days interval. A period of two to three weeks should be allowed to lapse before the crop is marketed for consumption.

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