The Gazetteers Department

Jowar stem borer (chilo zonellus, swinh).—The host plants of this pest are jowar and maize. Creamy white eggs are laid on leaves in clusters which hatch in six days. Young caterpillars bore into the stems and remain there for three to four weeks, after which fully grown caterpillars pupate in situ. The pupa period is 7 to 10 days and the total period of the lifecycle is 5 to 6 weeks. The pest hibernates as a larvae in stubbles. The pest causes damage to the crop for about 6 months from June to November. During this period the pest completes its life cycle at least four times.

The caterpillars are dirty white with many spots on the body and with a brown head. The full grown caterpillar measures about 1/3" in length. The moths are straw-coloured with fore-wings pale yellowish grey having minute dots on the apical margin and white hind-wings.

The caterpillars bore inside the stems causing thereby the drying of the central shoots called dead hearts. This causes reddening of stems and leaves. The extent of damage is about 4 to 5 per cent. As the pest is an internal feeder only, preventive and mechanical measures are found practicable and economic. They are (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, and (iii) the fodder to be fed to cattle should be cut into small pieces and fed.

Surface grasshoppers (chrotogonus sp).—The host plants of this pest are jowar, maize, groundnut, etc., and other millets. The eggs are laid in the soil at a depth of 0.05 to 0.08 m. (2 to 3 inches) along the bunds, field and even in fallow lands in batches of 40 to 60 during the period of October to December. The eggs remain dormant in the soil till the following June when they come out with the advent of the monsoon. The hoppers first feed on the grasses on bunds and then shift towards the field crops such as jowar, maize, etc. The hoppers develop into adults in about 70 to 80 days after which pairing takes place and egg lying commences. There is only one generation in a year and the pest is active from June to December. It is a minor pest and causes damage to the extent of 1 to 2 per cent.

The hoppers are about ¾" long, medium black coloured with various spots and a rough body surface. Nymphs and adults feed on leaves and tender shoots of the plants. Tender seedlings of jowar are also cut by them at ground level.

The pest can be controlled by destroying egg masses by ploughing and harrowing the fields especially along the bunds after the harvest of the crop. This may crush and expose them to the sun which may help to decrease the carry over of the pest. Insecticidal control consists of dusting 5 per cent BHC at the rate of 20 lbs. per acre.

Groundnut

Aphids.—Aphids are tiny, soft-bodied insects with a sucking type of mouth parts. A single apterous female gives birth to about 8 to 22 young ones called nymphs per day. It takes about four months before they reach the adult stage. Their lifecycle becomes complete in about a week's period. During its latter part, some winged members are produced in most species of aphids.

This is a very important pest as it reduces the vitality and yield of plants by sucking the sap and also acts as the vector of a serious virus disease commonly known as ' resette' of groundnut. The pest is of sporadic occurrence in most parts of the State. However, in some districts like Jalgaon and Dhulia it frequently takes the form of an epidemic.

The pest can be controlled by spraying the crop with 1 ounce of nicotine mixed with 5 gallons of water and four ounces of soap. The total quantity of mixture required per acre is 181.84 to 272.76 litres (40 to 60 gallons) at a time. The crops may also be sprayed with pyrocolloid in the proportion of one ounce pyrocolloid in 22.73 litres (5 gallons) of water. About 181.84 to 272.76 litres (40 to 60 gallons) of mixture is required for 1 acre.

Cotton

Jassids (empoasca devastans Dist.).—This is a pest of cotton, bhendi, potato and holly hock. Both nymphs and adults suck the cell sap from the leaves. As a result, the leaves turn yellowish and ultimately dry up.

The adult is wedge-shaped about 2 mm. long and pale green in colour. The front wings have a black spot on their posterior Parts. The nymphs are wingless and are found in large number on the lower surfaces of leaves. They walk in diagonal directions of their body. About 30 eggs are laid at a time by the adult females. The eggs hatch in 4 to 11 days. The nymphal stage remains from seven to twenty-one days during which period thee nymphs moult five times. The entire life cycle is completed in two or four weeks. The pest is particularly active during the monsoon season.

DDT dust is generally used as a control measure. However the use of DDT alone should be discouraged, as many times it leads to excessive increase in aphid. To prevent this, it is necessary that 5 per cent DDT be mixed with an equal quantity of sulphur before dusting. This insecticide, which is available ready-made gives a good measure of protection of about two weeks if rainy weather does not follow the dusting operation. DDT and sulphur mixture should not be used for Indian or Asiatic cotton, as sulphur scorches these varieties severely. On Asiatic cotton, however, jassid infestation is less due to its relative resistance to jassid attack. If, however, infestation appears, 5 per cent DDT may be used. DDT and sulphur mixture is safe only on the American varieties of cotton, which are also more prone to jassid infestation. 0.2 per cent spray of DDT plus 50 per cent (w/d) and sulphur (w/d) is very effective against jassids. Two to four ounces of endrin per acre or 0.01 per cent to 0.02 per cent parathion are also effective against this pest and are cheaper than the mixture of DDT and sulphur (w/d) mixture. But the latter has an advantage in that it prevents mites build up.

Boll-worms.—There are two types of boll-worms (i) spotted boll-worms (earias. fabia, S.E. insulana) and (ii) pink boll worms (pectinophora gossy-pilla, S.).

The host plants of both of these boll-worms are cotton, bhendi, ambadi and other malvaceous plants Eggs of these boll-worms are laid singly on leaves, flower buds, bracts, holls etc. They hatch within 4 to 6 days. Larval period in case of spotted boll-worms is 9 to 16 days depending upon the climatic conditions and pupation takes place inside the silken cocoons outside the bolls. In this stage it remains for 8 to 14 days. The total period of a life cycle is about 22 to 35 days.

In the case of pink bollworms, the caterpillars, on hatching, feed on developing flowers, seed or lint. The larval period is usually of about 3 to 4 weeks but some of them remain dormant in the seeds for a pretty long time for the perpetuation of the species. Pupation generally takes place inside the bolls or in the soil in silken cocoons from which moth emerges after about 10 days. The pest is active from July to December while the winter season is passed in the larval stage.

The adults of the spotted boll-worms have pale white upper wings with a greenish band in the middle. The moth of pink boll-worms is about ½ inch across the wings and is dark brown in colour. The first segment of the antenna has 4 to 6 staff hairs and the palps are long and curved upwards. Caterpillars when fully grown measure 1/3" long and are pink in colour with a brown head. Both the types of boll-worms have a number of black and brown spots on the body. The full-fed larva measures about ¾ inch in length.

In case of spotted boll-worms, caterpillars bore into the growing shoots of the plants in the initial stage of the crop. Later on, when the flower buds appear, the larvae bore into them and then enter the boll by making holes which are plugged with excreta. The infested buds and bolls are shed but if they remain on the plant, they open prematurely and consequently a lint from such bolls fetches low price in the market.

Unlike the spotted boll-worm, the caterpillars of the pink boll-worm never attack the shoots. They grow inside the bolls and cause shedding of them. The pest is more severe in case of American cotton varieties than of the indigenous ones. As the caterpillars bore the bolls, the entry holes get closed and it becomes difficult to spot out the affected bolls until such bolls drop. The following are some of the measures suggested for controlling the pest—(i) removal and destruction of stubbles to check carry-over of the pests to the next season; (ii) destruction of all the malvaceous plants growing in off season which serve as alternate host for the pest; (iii) fumigation of seed before sowing with carbon-di-sulphide at the rate of two ounces per 15 cubic feet or heating the seed at 145°F to destroy the hibernating pink boll-worm larvae; (iv) quick removal and destruction of the affected plant parts in the early stage of the pest incidence; (v) six dustings with 10 per cent DDT plus 20 per cent lindane plus 40 per cent sulphur mixture or with 1 per cent endrin dust or (vi) six sprayings at fort-nightly intervals with endrin at the rate of 6 ounces per acre, starting from a month prior to flowering have been found to be effective in reducing the pest incidence. It is desirable to add equal quantity of sulphur to avoid subsequent mite incidence.

Other Minor Pests

Cotton aphis (aphis gossipich).— These insects push their beaks into plant tissues in order to suck cell sap and remain in this position for a long time. As a result, leaves get curled up. The pest can be controlled by spraying a mixture composed of a pound of nicotine sulphate, 2.68 kg. (five pounds) of soap and 363.68 litres (eighty gallons) of water spraying with pyrethrum extract mixed with water in the proportion of 1: 1,000 also gives satisfactory results. The use of fish oil resin soap for spraying, about eight ounces in 18.18 litres (four gallons) of water is also common. 454.60 litres (Hundred gallons) of this mixture could be used for one acre.

Bond ali—bond ali, the spotted boll worm.—In the beginning of the cotton season, caterpillars bore into growing shoots of the plant when flower beds appear, larvae bore into them and later into bolls which show holes plugged with their excreta. This causes infested buds and bolls either to shed or open prematurely. Lint from such bolls fetches a low price. There are two species of the spotted boll-worm. Adults of one species have pale, white upper wings with a broad greenish band in the middle (earias fabia): while those of the other species have completely green upper wings (earias insulana). The pest is active practicall throughout the year and generates several times in an year.

As the pest is an internal feeder, only preventive methods are feasible. After harvest, stubbles are removed and destroyed to prevent breeding of the pest in the off season. This is often done by plant pullers specially devised by the agriculture department. The clipping and destruction of the initially infested top shoots is properly attended to during the earlier stages of the crop. Malvaceous weeds are destroyed during the off season, as otherwise they harbour the pest and carry it over to the next crop. Recent experiments show that seven dustings with a mixture of 10 per cent sulphur or one per cent endrin, at fort-nightly intervals, reduce the degree of infestations. Further, four ounces of endrin per acre sprayed five times at intervals of fifteen days also give satisfactory results.

Bond ali, the pink boll-worm (plalyedra gosypiellas):—The caterpillars feed inside bolls which begin to shed gradually. The pest destroys American cotton varieties more than the indigenous ones. As caterpillars enter bolls, entry holes are closed, thereby making it difficult to spot out affected bolls until they decay and drop. Unlike spotted boll-worms, caterpillars do not attack shoots. The pest is active between July and December. The winter season is passed in the larval stage when the pest remains curled up in a small cocoon in stored seed, in soils or in bolls. Larvae develop faster in adequate moisture and later fresh brood infects the new crop. Before sowing, cotton seeds are fumigated with carbon di-sulphate at one ounce per fifteen cubic feet or by heating the seed to 145° Fahrenheit larefully without injuring it. Further, early infested bolls are promptly picked-up and destroyed.

Dahiya.—dahiya, the grey mildew of cotton:—It has assumed serious proportions in recent years. In the case of severely affected plants defoliation takes place which adversely affects the yield.

Mar.—mar, the cotton wilt (fusarium rasinfectum): —Leaves of affected plants become yellow, drop and shed. Affected plants, when split, open through top root and stem and show brown discolouration of the vascular system. Wilt may appear suddenly or attack the plants at any stage of its growth. A partial wilt is also common, the affected plants remaining stunted. Branches of partially affected plants, when pulled out, exhibit peculiar vascular discolouration so typical of wilt. This disease is neither amenable to direct control measures nor can it be exterminated by any known cultural methods, since the fungus causing wilt is a soil dweller and remains alive in the soil for a number of years. Crop-rotation is, therefore, of little value. Growing cotton strains, resistant to wilt, is hence the only practicable method of combating the disease. Virnar, a resistant strain of G. arboreum, is under extensive cultivation in this tract.

Mool-kujne.—mool-kujne, the root-rot of cotton: It is a major disease resulting in a heavy damage to the crop. Affected plants wilt suddenly and completely. When initial wilting is not permanent, affected plants recover on cool nights, in wet weather or in irrigated fields, but complete recovery is rare. Affected plants can be easily pulled out and all roots, except the tap root are invariably found in a damaged condition. The bark can be easily peeled off. leaving a brown discolouration of exposed area. The drying of plants occurs in circular patches in the held, growing of resistant varieties is the only practicable method of controlling the disease but unfortunately no resistance qualities are observed so far, both in American and indigenous varieties.