AGRICULTURE AND IRRIGATION

PESTS AND DISEASES

Crops in the district as elsewhere, are susceptible to various insect pests and pathological diseases. In the following pages a brief account of some of the more important pests and diseases and measures to control them is given. No attempt has, however, been made to determine the extent of damage caused in all the cases as it varies with the severity or otherwise of the infestation in any particular year.

Of Jowar.

Jowar Stem Borer (Chilo zonellus, Swinh) locally known as Khod Kida causes considerable damage to both kharif and rabi jowar. Caterpillars bore inside the stems of the young plants and feed inside as a result of which growing shoots wither and dry up causing dead hearts. Summer jowar is frequently found to be heavily infested by this pest. It also affects paddy maize and grasses. The extent of damage caused varies between four and five per cent.

Full-grown caterpillars are dirty white with many spots on the body with a brown head. The moths are straw-coloured with pale yellowish grey fore-wings, having minute dots on the apical margin and white hind-wings. The pest hibernates as larvae in stubbles.

As stem borers are internal feeders only preventive measures are found practicable as also economic: (i) The affected plants containing the caterpillars should be pulled out and destroyed promptly (ii) After harvesting the crop, the stubbles should be removed and burnt to destroy the hibernating larvae (iii) Before storing the fodder to be fed to cattle, it should be chopped into small bits.

Jowar Stem Fly (Atherigona indica) is locally known as Khod Mashi. The maggots bore inside the plants of the seedlings and kill the growing shoots. Besides jowar, other millets are also susceptible to this pest. In the early stages of the crop the pest is found to be serious.

Its maggots are legless tapering anteriorly. The adults are similar to house-flies but are much smaller and bear a few dark spots on their dorsal side. Full grown maggots pupate inside the infested stems.

The following two control measures have been found to be effective: (i) Dead seedlings should be promptly uprooted and destroyed along with the maggots, (ii) The seed rate may be increased to make up or minimise the loss.

Flea Beetle (Chaectocnema indica) locally known as Pisum or Bhungre is another serious pest of jowar. In the eastern parts of Maharashtra, this pest causes serious damage to jowar. Sann hemp is very much susceptible to a species of this pest. The beetles generally feed on the middle part of the leaf-blade and not on the border as is the case with caterpillars and grasshoppers, with the result that numerous small holes are bored on the leaf surface. Their life history has not been traced so far with any accuracy, but the young ones i.e. the grubs are supposed to be root-feeders.

They are blackish small and oblong in shape with a thickened hind pair of legs which enables them to hop about. Some species are found to be brownish in colour.

The pest can be controlled by giving a dusting of 10 per cent BHC. If the attack is not severe 5 per cent BHC dusting will get rid of the pest. Treatment with 0.05 per cent of aldrin or 0.15 per cent of malathion is also found to be effective.

Army Worms (Cirphis unipuncta) locally known as Lashkari Ali affects mainly jowar and paddy. Its other host plants are maize, bajra and other cereals. The caterpillars feed on the leaves resulting in the destruction of the growing shoots. In case of a severe attack they completely defoliate the plant as they are habituated to feeding en masse. Kharif crops are liable to more damage than rabi ones. They are night-feeders and remain hidden in the leaf-sheaths or whorls or the clods underground during the day time. When the food exhausts they migrate to another field and for that reason they are known as ' army worms '.

Full-grown caterpillars are smooth-bodied, dull greenish coloured with broad light coloured stripes running along the length on either side of the body. Two types of moths are found. One is brownish red with prominent spots on the anterior margin of the wings, the hind-wings being pale in the middle with dark borders. The second type 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 having longitudinal bands is also known to infest jowar. Their habits as also the measures to control them are the same as those of the flea beetle. Full grown caterpillars pupate in the soil. The pest is active from June to November. It is observed that the pest assumes epidemic form when a long, dry spell follows a good start of monsoon. However, if heavy showers occur thereafter it shows a tendency to subside.

The pest may be overcome by adopting the following measures: (1) Egg masses should be collected and destroyed. (ii) If the attack can be localised, the caterpillars may be collected by employing labour and destroyed. (iii) After harvesting the crop, the infested field should be thoroughly ploughed in order to expose the pupae. Insecticidal measures have also been found very effective. If dusted with 5 per cent BHC or aldrin dust at the rate of 30 lbs. per acre, the pest can be successfully controlled. As the pest is a night-feeder evening dusting, if there is less breeze, is found to be more effective; 50 per cent BHC wettable powder sprayed after diluting one pound in 25 gallons of water gives a satisfactory result. About 80 to 100 gallons of such water is required to cover one acre. 5 per cent of BHC poison bait, when broadcasted in the evening, will also control the pest provided it does not rain and the soil is dry.

Delphacids (Peregrinus maidis, Asham) and Aphids are responsible in causing a sugary secretion on the leaves and in the whorls which damages the growing shoots of the plants and checks their further growth. The symptoms are locally known as chikta and the pest affects severely, especially rabi Jowar. Delphacids and Aphids are locally known as Tudtude and Mava respectively. Its host plants besides jowar, are sugar-cane, maize and grasses.

Delphacids are wedge-shaped, greenish brown in colour with blackish spots on the wings. In case of aphids the adult is oblong in shape 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.

So far, no definite control measures have been evolved to fight and overcome this pest and its sugary secretion, and the problem is still under investigation. However, spraying with 0.02 per cent diazinon, thiometon endrin, or dusting with 5 to 10 per cent BHC dust at the rate of 20 lbs. per acre helps reduce the intensity of the infestation though not to wipe it out. It is expected that measures will soon be evolved to effectively fight this pest.

In addition to the pests noted above, jowar is also susceptible to various diseases like smuts, downy mildew and leaf rust.

Grain Smut (sphaceolotheca sorghi) (Link Clinton) is locally known as Kani or Dane Kani and affects both kharif and rabi jowar. The disease is seed-borne and threshing yards are the sources of infection of this disease. While in case of mild attacks the percentage decrease in yield ranges from two to five, in case of heavy attacks it may rise upto 10 per cent.

The peculiarity of this disease is that it cannot be detected until the earhead comes out. The diseased earheads do not form normal grains but spore-sacs in place of grains. The affected ovaries turn into conical porcelain white sori which contain black powder consisting of millions of chlamydospores of the fungus.

By treating the seed with sulphur (300 mesh fine) at the rate of 100 gms per 30 kg of seed the disease can be effectively controlled. Other organo- mercurial seed dressers can also be used at the same rate.

Loose Smut (Sphaceolotheca crucenta (Kuhn Potter) locally known as Kajali does not differ from that of the grain smut in any of its aspects including the control measures, with the exception of symptoms. Even the symptoms are nearly the same, but with this difference that in case of loose smut the wall of spore-sac gets ruptured and the black mass of chlamydospores is exposed giving a blackish appearance to the affected earhead.

Leaf Rust (Puccinia purpurea. Cke) locally known as Tambera is an air-borne disease and affects jowar during its growing period. Reddish brown pustules appear on the leaves breaking and letting out red mass of uredospores later turning black. In case of a severe attack yield reduction amounts from 5 to 10 per cent.

Use of resistant varieties of seeds is the only effective method of controlling the disease and preventing the occurrence of epithytotic.

Downy Mildew [Sclerospora sorghii (Kulk) Weston & Uppal] locally known as Kevada is a soil-borne disease caused due to oospores shed in the soil and the debris of the previous year's crop in the field. Downy white growth appears mostly on the lower surface of the tender leaves. The upper surface also becomes yellowish and the leaves get shredded.

It causes 3 to 10 per cent reduction in the yield. The disease occurs seasonally mostly from August to September. It can be controlled by systematic rogueing and burning of the affected plants. It can also be controlled by crop rotation and sowing of resistant varieties of seed.

Of Paddy.

Stem Borer (Schoenobius bipunctifer) locally known as Khod Kida as the jowar Stem borer is known, causes heavy damage to paddy reducing the yield considerably. The caterpillars bore inside the stems of the paddy plants as a result of which the central shoots wither away and die. If the infestation takes place at a later stage the shoots bear only empty earheads. The damage caused can be recognised from the appearance of whitish shoots.

Moths are straw-coloured with yellow fore-wings bearing a black dot on each side and white hind-wings. Full grown caterpillars are pale yellowish, white and smooth with an orange yellow coloured head. Even after harvesting, the pest lingers in the stubbles left in the field until the next monsoon and becomes active by June.

Being an internal feeder only preventive measures are practicable. These are: (i) Collection and destruction of the stubbles after the harvest (ii) In the early stages of the attack the affected shoots along with caterpillars should be picked out and destroyed. (iii) Egg masses, which are generally laid on leaf-tips, should be collected and destroyed.

Swarming Caterpillar (Spodoptera mauritia) locally known as Lash-kari Ali is another serious pest of paddy. It also affects jowar and other cereals. Immediately on hatching, the caterpillars feed on grass or young paddy seedlings, thereby destroying the plants. They are active only during the night and during the day remain in hiding in leaf whorls and sheaths and the soil, if it is not flooded.

The moths are stoutly built with dusky brown hind-wings and dark brown fore-wings with a black spot and an irregular wavy light line near the ends. Full-grown caterpillars are dark greenish with a slight yellow tinge. The presence of white longitudinal dorsal stripes along the length of their body readily distinguishes them from other caterpillars. The head is dark and well chitinished. The pest multiplies rapidly when there is a long break in rains after a good start.

This pest can be controlled by adopting the following measures: (i) Protection of seed beds by deep trenching with steep sides, (ii) Hand collection of egg masses and their destruction. (iii) As the larvae hide in soil-clods during the day time the field should be planked to trap them, (iv) Dragging a thick rope across the field may be resorted to after flooding the affected field so that the caterpillars in the leaf-sheath and whorls drop into the water, (v) If the attack can be localised, the caterpillars may be hand-picked and destroyed, (vi) Clean cultivation by removing grasses with a view to starving the emerging caterpillars may be tried with good results, (vii) Poison bait spread in the evenings helps in checking the pest. (viii) The affected field should be ploughed after the harvest so as to expose the pupae.

The pest can also be successfully controlled by dusting with 5 per cent BHC at the rate of 20 to 30 lbs. per acre. As the caterpillars are night-feeders, evening dustings give better results. When rains are frequent, spraying BHC water-dispersible powder by diluting 5 lbs. of 50 per cent BHC in 100 gallons of water can be tried. For effective control sixty to 100 gallons of spray should be used per acre.

Paddy Grasshopper (Hieroglyphus banian) is locally known as Naktode and besides paddy also affects sugar-cane and grasses. Both the nymphs and the adults feed on the plant foliage and the earheads. The adults are medium sized and uniformly greenish without spots, with the hind libia-coloured blue. This grasshopper is distinguished from other types by the presence of two to three dark black streaks immediately behind the head on the prothorax. The brownish nymphs turn greenish as they grow.

The pest can be controlled by scraping the bunds and digging out the low lying areas after the harvesting of the crop in order to expose the egg masses. Bagging the hoppers in the early stages of attack, when they are fairly big, may also prove useful. At the rate of about 20 to 30 lbs. per acre, a 5 per cent BHC bait may be spread. This measure is found more practicable in case of sugar-cane, especially in the early stages when the hoppers feed on grasses on bunds. Dusting with 5 per cent BHC at the rate of 20 to 25 lbs. per acre controls the pest effectively. In case of migration from the adjoining fields, two to three dustings have to be given.

Blue Beetle (Leptispa pygmoea) is locally known as Nile Bhungre and affects grasses besides paddy which is the main host plant. Beetles generally feed on the green shoots and leaves of the young paddy crop with the result that plants turn white and dry up. The infestation generally takes place before flowering.

The beetles are dark greenish blue, smooth and slightly rectangular. On hatching, the grubs feed on green portion of the upper surface of the leaves. During the off season the pest hibernates in wild grasses probably as an adult.

This pest can be controlled by collecting the beetles by means of hand-nets in the seed beds and destroying them. Crude oil at the rate of four to five bottles per acre, may be added to the flooded fields and the beetles dislodged in it by drawing a thick rope across the fields or by using a broomstick. However, the pest can be more easily checked by dusting 5 per cent BHC dust at the rate of 15 to 20 lbs. per acre or spraying 0.2 per cent BHC spray prepared by adding four lbs. of 50 per cent BHC water-dispersible powder to 100 gallons of water. At least 60 to 80 gallons of such liquid should be used per acre. Precautionary measures such as clipping the tips of the seedlings before transplanting so as to get rid of a majority of the eggs and dipping the seedlings in 0.2 per cent DDT water suspension obtained by mixing 4 lbs. of 50 per cent DDT water dispersible powder in 100 gallons of water are also found to be very effective.

Gall Fly (Pachydiplosis oryzae) is locally known as Kane and paddy is its principal host plant. It is also known to affect some varieties of wild plants. Some strains of paddy like Red Helga and Jaddu are known to be more susceptible to the gall fly than White Helga and Maskati which show relatively good resistance.

The young larva after hatching creeps down the leaves and enters the bud and damages it. This checks normal apical growth which results in forming an oval chamber called  'silver shoot' round the maggot. Such buds do not produce a normal stem to bear an earhead and leaves. The damage inflicted by this pest can be readily distinguished from that of the stem-borer, in that whereas Kane produces a tube-like structure in place of the growing shoot, in case of the stem borer, the normal looking shoot dries up. Infestation is highest during the tillering stage and the subsequent broods of this pest damage the crop to the maximum extent. The crop does not get any time to recoup as the new brood again infests the tillers. To begin with the pest appears on giant grass (Paspalum sp.) and then shifts over to the crop. The infestation takes place from July to November.

Gall fly is a serious pest and so far no satisfactory measures have been devised to control it effectively. However, a high humidity and subsequent parasitization are to a large degree responsible for a natural check of the pest in some years. Another way to escape the pest is the use of resistant varieties and early transplantation. Chemical methods of control also have not been established so far. A possible method of containing the pest is the removal of " silver shoots " as and when they form. Of the insecticides tried so far 01 per cent parathion emulsion spray has shown some result when five to seven applications were given at the rate of 100 to 150 gallons per acre at weekly intervals.

In addition to the above noted pests paddy is also susceptible to a variety of other pests like Rice Hispa locally known as Karpa, Rice Earhead Bug or Lombivaril Dheknya, Rice Case Worm or Suralitil Ali Rice Skipper or Pane Gundalnari AH, crabs or Khekade, Paddy Jassid or Tudtude etc. However, these pests with the possible exception of crabs, do not pose a serious menace to the crop as there are remedial measures to control them easily and very effectively. Though crabs do not inflict much damage on the crop as such, they seriously damage the bunds.

Paddy is also susceptible to very many diseases besides pests of which a few of the important ones are given below:-

Paddy Blast (Piricularia oryzae, Cav.) locally called Karpa is both a seed-borne and air-borne disease. Sources of infection are infected seeds, plant debris and wind. The disease first manifests on leaves in the form of small spindle shaped brown spots with white centre on seedlings. As the spots widen they coalesce with each other and subsequently the plant dies. If the crop is attacked at the time of the emergence of the earhead the necks are found to be rotten and black. Such earheads do not develop grains. If the attack is in the post-grain formation stage the neck becomes too weak to support the weight of the panicle and it breaks resulting in grain shedding. The disease occurs seasonally and attacks the seedlings from July to August and the grown up crops from September to November. In case of mild attack the percentage loss in grain yield ranges from 5 to 10 and 45 to 75 in case of a severe attack.

The following control measures have been found to be effective: (i) Seed treatment with organo-mercurial seed dresser containing 1 per cent organic mercury at the rate of 100 gms per 30 kg of seed. (ii) Before transplanting, the seedlings should be dipped in bordeaux mixture. (iii) Upto flowering time one to two sprayings of bordeaux mixture 3: 3: 50 or any copper compound containing 50 per cent metallic copper could be given, (iv) By using resistant seed varieties. Early Ambemohor 39, Kolhapur-scented, Patni-6, Bhadas-78, Krishnasal-10 and Antrasal-10,61,90,200 are found to be resistant to this disease.

Bacterial Blight of Paddy (Xanthsmonas oryzae, Mueda and Ishtyama, Dowson), locally known as Karpa or Kad Karpa is a seed-borne disease, sources of infection being affected seed, and plant debris of the previous affected crop. The symptoms of the disease are the appearance of water soaked streaks and marginal blighting with yellow bacterial ooze at the margins of the leaves of the paddy plants. The marginal blighting extends further resulting in the death of the leaves. The disease affects the crop in August and September causing a percentage loss in yield to the extent of 20 to 25.

The disease can be controlled by adopting the following measures: (i) Destruction of the plant debris after the harvest. (ii) Treating the seeds with organo-mercurial compounds at the rate of 2 to 3 gms per one kilogram of seed. (iii) Spraying the seed-bed with 0.02 per cent endrin for insect control, (iv) Spraying the transplanted seedlings with 0.02 per cent endrin and 0.3 per cent copper oxychloride thrice at an interval of 20 days. 20 to 40 lbs. of potash should be used per acre as it tends to reduce the disease.

Helminthosporium Leaf Spot (Helminthosporium oryzae, Breda de haan) locally known as Tikkya is another disease that affects the paddy crop throughout its growing period. It is a seed-borne disease, the infected leaves of seedlings and adult plants showing spots with white centre and yellow halo. If the attack takes place at the grain formation stage there may be sterility. This disease can be controlled by adopting the measures suggested for Paddy Blast.

Of Wheat.

Wheat Stem Borer (Sesamia inferens, Wlk.) locally known as Khod Kida also affects maize in the dry weather. Sometimes winter wheat crop is also found to be infested by this pest. The caterpillars bore inside the stems causing ' dead hearts '. The initial feeding of the caterpillar on the whorl, while entering the shoot, gives rise to numerous holes on the leaves. This causes the plant to dry which leads to reddening of the stems.

The full-fed caterpillar is about an inch long, flesh coloured, smooth with black head and dark spots on the body. Each dark spot bears a hair. They are found in the stems of the affected plants. The moths are small and straw-coloured. Their fore-wings have a marginal dark line and the hind-wings are white.

Inside the leaf-sheaths of the stem creamy white eggs are laid in clusters. The total period from the egg stage to the adult stage is six to seven weeks. In the cold weather, however, this period may be prolonged. The caterpillars pupate inside the stems.

Being internal feeders only preventive measures are found practicable and economic. These are: (i) In the early stages of infestation the plants showing dead hearts should be uprooted and destroyed promptly. (ii) After harvesting the crop the stubbles should be collected and burnt so as to destroy the hibernating larvae. Chemical control measures have so far yielded no fruits.

Wheat is also susceptible to a variety of diseases. These are:

Black Stem Rust (Puccinia graminis tritici, Erike and E. Henn) is locally known as Tambera and is a serious disease of wheat causing 60 to 75 per cent loss in grain yield under severe conditions. It is air-borne and is spread by spores carried by the wind. The disease appears in the form of reddish brown elongated linear eruptive spots known as pustules mostly on the stems. However, pustules appear on the leaves and leaf-sheaths and awns in the early part of the season. When these pustules are rubbed on the thumb, they leave a brownish smear. This reddish brown powder contains spores called uredospores. Later in the season this endophytic mycelium gives second type of black coloured sori or black pustules at the same erupted spot or by its side. These black pustules contain blackish powder containing spores called teleutospores, which means last spores. As the name signifies taleuto stage appears at the maturity of the crop. The disease occurs from November to February.

The disease can be overcome by growing the following resistant varieties of wheat viz., Kenphad-25, MED-345, KON, Hy-65, NI-315, NI-146,' NI-284-S, NI-28 and NI-62 for irrigated crops and selection 59 and 125 for dry crops.

Loose Smut [Ustilago tritici (pers) Roaster] locally known as Kani or Kajali is another disease of wheat causing a decrease in yield to the tune of 5 per cent. The disease is seed-borne and is caused by internally infected seeds. It affects the crop from January to March.

The disease is detected only when the earheads are formed. The earheads become black and every part of the earhead save rachis and awns get saffected. In place of grains a loose blackish powder is formed.

Infection being internal i. e., inside the seed, dressing with fungicides is ineffective and hence a special method has been devised to remove this type of infection. The process consists in soaking the seeds in cold water for about four hours from 8 to 12 A. M., then drying them up in the hot sun on galvanised iron sheets for four hours and then cooling them down in the shade for some time. After this process is over the seeds should be sprayed with insecticides like pyrethrum, DDT. etc.

Foot Rot (Fusarium moniliforme sheld) locally known as Mulkujvya is both a seed and soil borne disease of wheat. The extent of damage caused ranges from 5 to 6 per cent. The pathogen attacks at the collar region as a result of which the plant wilts and dies. It affects the crop throughout its growing season. It can be controlled by treating the seed with organo-mercurial compounds containing one per cent active mercury at the rate of two to three grams per one kilogram of seed. Deep ploughing may also help to stave the disease.

Of Bajri.

Blister Beetle (Zonabris pustulatd) locally known as Hinge or Bali is a pest of bajri also affecting jowar, cucurbits and beans. The beetles feed on the pollen and the petals of flowers and thus reduce the setting of grains in the earheads. The larvae feed on the eggs of the grasshoppers which thus is an advantage.

The beetles are black with yellowish brown stripes across their wings and over an inch long and about half an inch thick. Its other species are smaller, about three fourth of an inch long with a light brown or greenish blue colour. All of them have rather a soft body and their wings are also thinner than those of other beetles. When crushed on the human body, it causes a blister and hence the name blister beetle.

Whitish eggs are laid in the soil in masses which hatch in about a fortnight. The larvae feed on the eggs of the grasshoppers laid in the soil. The beetles emerge from pupae and remain active from August to December. Only the adult stage of this pest causes damage to the crops.

Preventive measures consists in collecting the beetles by using hand-nets and destroying them. As the beetles are attracted towards light, light-traps may be used. However, this method is not effective. Insecticidal results are more satisfactory. 5 per cent BHC dust is effective against this pest if dusted properly at the rate of 20 lbs. per acre.

Tur Plume Moth (Exelastes atomosd) locally known as Pisari Patang is a pest of tur and also affects wal. The caterpillars bore into the green pods and feed on the developing seeds.

Of Tur.

The moths are slender, not more than 1/2" long and are grey with long narrow wings. The front wings are divided into two parts and the hind- wings are cut into three provided with a fringe-like border. The full-grown caterpillars are about 1/2" long greenish brown in colour and are fringed with short hair and spines.

Minute eggs are laid singly on the tender shoots, leaves, flowers, or pods which hatch in about five days. On hatching the caterpillars first scratch the surface of the pods and gradually enter inside by cutting holes. They become full-grown in about four weeks' time. 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.

Preventive measures consist in collecting the caterpillars by shaking the shoots and pods in small trays containing kerosenized water and avoiding the taking of leguminous crops in the same fields in successive years. The insecticidal measures given under gram pod borer may be tried with considerable advantage.

Tur Wilt (Fusarium oxysporium f. udum) locally known as Ubhal or Mar is a soil borne disease of tur and affects the crop throughout its growing period. The disease is endemic and the percentage of wiltings is from 2 to 5.

The affected plants appear sickly, leaves drop down and ultimately the plants wither away and die. If the roots of the affected plants are split open brown discolouration of the vascular tissue is seen. So far the only remedy found against this disease is to grow resistant varieties.

Gram Pod Borer (Holiothis obsolata) locally known as Ghatyatil Alt is a pest which besides gram, also affects cotton, tobacco, tomato, peas, ganja and safflower. These are its principal host plants. The caterpillars feed on tender foliage and young pods. They bore holes in the pods and eat the developing grams by inserting the anterior half portion of their body inside the pods. The pest is active from November to March.

The moths are stout, light yellowish brown, with a wing expanse of 1½". While the fore-wings are pale brown with some black dots, the hind ones are lighter in colour with smoky dark markings. Full-grown caterpillars are greenish with dark broken grey lines along the sides of the body. They are 1½" to 2" in length.

Shining greenish yellow eggs, spherical in shape are laid singly on the tender parts of plants which are hatched in about six to seven days. In 14 to 15 days they become full-grown, descend to the ground and pupate in earthen cocoons in the soil near the plants. Their pupal period lasts from a week to a month.

Preventive measures include hand-picking of caterpillars in the early stages of attack and their destruction. To expose the pupae hibernating in the soil the field should be thoroughly ploughed after the crop is harvested. The pest can also be controlled by 0.2 per cent DDT spray obtained by diluting 1 lb of 50 per cent water dispersible DDT powder in 25 gallons of water. Generally a young crop requires about 60 to 80 gallons of such mixture per acre and a grown up crop about 100 gallons.

Boll Worms locally known as bond ali are of two types (a) Spotted Boll Worms, and (b) Pink Boll Worms.

(a) Spotted Boll Worms (Erias fabia S. & E Insulana B) locally known as Thipkyanchi Bond-ali is a serious pest of cotton, its other host plant being bhendi, ambadi and other malvaceous plants.

Of Cotton.

Spotted Boll Worm caterpillars bore into the growing shoots of the plants in the initial stage of the crop. Later when the flower buds appear the larvae bore into them and enter the bolls by making holes which are plugged with excreta. This results in shedding the buds and bolls. However, if they still remain they open up prematurely and consequently lint from such bolls fetches a low price.

(b) Pink Boll Worms (Pectinophora gossypiella, S.) is locally known as Shendri Bond-ali and unlike the spotted boll worms, the caterpillars never attack the shoots. Instead they feed inside the bolls and make them drop down. The pest is more harmful to American varieties of cotton than the Indian ones. As the caterpillars bore inside the bolls, the entrance holes get closed and it becomes difficult to spot out the affected bolls until they drop down or open up prematurely.

The life history, marks of identification and the control measures are more or less the same in case of both the boll worms and hence are grouped together.

The adult of spotted boll worms have pale white upper wings with a greenish band in the middle. However in case of adults of the pink boll worm the upper wings are totally greenish. The caterpillars of both the species are brownish white and have a dark head and prothoracic shield. Spotted boll worms bear a number of black brown spots on the body and hence the name. Full fed larvae measure about 3/4" in length.

Eggs are laid singly on leaves, flower buds, bracts, bolls etc. They hatch within four to six days. In case of the spotted boll worms the larval period lasts from nine to sixteen days depending upon the climatic conditions. Pupation takes place inside silken cocoons, outside the bolls, in which stage they remain for eight to fourteen days. The total period of the life cycle ranges from about 22 to 35 days. The pest is active from July to November.

In case of the pink boll worms, the larval period lasts from three to four weeks. Some of them remain dormant in the seeds for a long time for the perpetuation of the species. Generally, pupation takes place inside the bolls or in soil in silken cocoons from which moths emerge after about ten days. The pest becomes active from July to December. The winter season is passed in the larval stage.

The following are the measures prescribed for the control of these pests: (i) Removal and destruction of stubbles to check carry over of the pest to the next season. (ii) Destruction of all the malvaceous plants growing in off season which serve as alternative hosts for the pest, (iii) Seed fumigation with carbon disulphide at the rate of two ounces per 15 cubic feet before sowing or heating the seed at 145° F to destroy the hibernating larvae of the pink boll worm., (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 D. D. T. +2 per cent lindane +40 per cent Sulphur mixture or with 1 per cent, endrin dust. Six sprayings at a fortnightly interval with one ounce of 20 per cent. E. C. endrin mixed in four to six gallons of water starting from one month prior to flowering have been found to be effective in reducing the pest incidence. It is desirable to add an equal quantity of sulphur to avoid mite incidence.

Red Cotton Bug (Dysdercus sigulatus, Fabr.) locally known as Tambdya Dheknya is a minor cotton pest its other hosts being bhendi, deccan hemp and hollyhock.

Both nymphs and adults suck plant sap thereby greatly impairing the vitality of the plant. By feeding on the seeds they lower their oil content. The excreta of these insects soils the lint. The infected seeds become useless for sowing. From October to February the pest remains active.

The adult is bright red, about half an inch long, with eyes scutellum, antenna of black colour. A series of white transverse bands are present on the ventral side of the abdomen. The nymphs are wingless, but resemble the adults in colour.

Bright yellow rounded eggs are laid in the soil in masses near the plants. These are hatched within seven days. Nymphs which are bright red pass through six instars in 30 to 35 days before reaching the adult stage. The total period of their life cycle is about six to eight weeks. During winter the pest hibernates in the adult stage.

The pest can be controlled by collecting the adults and the nymphs in trays containing kerosene mixed with water. This is done by shaking the plants. In case the pest becomes serious, which rarely happens, the crop may be treated with 5 per cent B. H. C. dust.

Jassids (Empoasca devastans, Dist.) is locally known as Tudtude, cotton being its main host plant. Its other host plants are bhendi, brinjal, potato and hollyhock. The pest is particularly active during the monsoon season.

Nymphs as well as adults suck the cell sap from leaves as a result of which the leaf margins turn yellowish. In case of excessive infestation the leaves redden and dry up as a result of which the growth is stunted.

Pale green in colour, the adult is wedge-shaped and 2 mm. in length. The front wings bear a black spot on their posterior parts. The nymphs are wingless and are found in large numbers on the lower surface of the leaves. They walk diagonally.

About 30 eggs are laid at a time in the tissue of the leaf-vein. The eggs are hatched in four to eleven days. The nymphal stage lasts from 7 to 21 days during which period they moult five times. In two to four weeks the entire life cycle is completed.

By adopting the following measures the pest can be controlled: 5 per cent D. D. T. dust at the rate of 15 to 20 lbs per acre mixed with an equal quantity of sulphur is known to be effective. The use of D. D. T. alone should be discouraged as it leads to excessive multiplication of mite population. It is to counteract this effect that sulphur should be mixed. This insecticide, which is sold ready-made, gives a good measure of protection for about two weeks provided rains do not follow the dusting operation. However, care should be taken to avoid the use of this mixture on Indian or Asiatic cotton varieties as it severely scorches these varieties. It may be added here that these varieties are not liable to jassid infestation. If infestation takes place only 5 per cent. D. D. T. may be used. The mixture is practicable only on American varieties which incidentally are more prone to jassid attacks. 0.2 per cent, spray of D.D.T. 5 per cent (w/d) and sulphur (w/d) is very effective against jassids. Also effective against this pest and cheaper too than D D.T. plus sulphur mixture is endrin applied at the rate of two to four ounces per acre or 0.01 to 0.02 per cent, to parathion. D. D. T. and sulphur mixture has the advantage in that it prevents mite build up.

Aphids (Aphis gossypii, Glover) locally known as Mava is another pest of cotton, its other hosts being bhendi, potato, chillies, brinjal and watermelon. The nymphs as well as adults suck the cell sap with the result that leaves turn yellowish and finally dry up.

The adult is oblong dark yellowish green in colour and is about one m.m. in length. It has two projections called cornicles on the dorsal side of the abdomen. It is mostly found in the wingless stage.

The alate and apterous forms reproduce parthenogenetically and viviparously. A single apterous female produces eight to 22 young ones a day. Before reaching the adult stage they pass through four moults. The duration of their life cycle lasts from seven to nine days.

The following control measures are known to be effective: (i) spraying with nicotine sulphate at the rate of one pound in 80 gallons of water with five pounds of soap, (ii) Spraying with pyrethrum extract in the proportion of one part in 1000 parts of water gives satisfactory results. Nearly 80 to 100 gallons of spray are required per acre. 2 ozs. to 4 ozs. of endrin per acre or 0.01 per cent to 0.02 per cent parathion are also effective against cotton aphids.

Mealybugs (Ferrisiana virgata, CKLL.) is locally known as Chiktya and affects cotton, cashew, cocoa, jute, soyabean, pepper and many other crops. Both the nymphs and adults suck the juice of the leaves and tender shoots as a result of which plants give a stunted and whitish appearance. The feeding also causes curling and chlorosis. It is also reported to be acting as a vector of a virus disease. The pest is active from June to October.

The adult female is pale yellow in colour with its body covered with white meal and glossy threads, the caudal filaments attaining about half the length of the body. Its average length is about 2.6 to 3m.m. Newly hatched nymphs are light yellow in colour. However, the males are rare and winged. Adults and nymphs are seen congregating on the lower surface of the leaves and shoots of cotton plants.

The female is capable of reproducing parthenogenetically. Eggs hatch in about 19 to 29 minutes. Whereas the female undergoes three nymphal instars, the male undergoes four. The total nymphal period lasts for about 18 to 19 days, and the total life cycle from the egg to oviposition about 42 to 56 days.

Spraying with 1 per cent, fish oil rosin soap, 0.3 per cent, diazinon or parathion and 0.10 per cent malathion helps reduce the pest infestation.

Mites (Eriophes gossypii, Bank.) known by the same name locally also is a polyphagous species, but its main host plants are cotton, bhendi and castor. Both the adults and nymphs usually feed on the lower surface of the leaves as a result of which they become silvery white and ultimately dry up. In cases of extreme infestation complete defoliation of plants is caused.

The larva which undergoes three moults before becoming an adult, is flesh coloured with three pairs of legs. Adults are minute sized creatures with an oval body and four pairs of legs. The female lays about 10 to 100 creamy, spherical and semi-translucent eggs which hatch in four to Seven days time. Within six to ten days the nymphs become adults which live from ten to thirty days. The total life cycle is completed in three to four weeks.

Spraying with 0.05 per cent aramite, 0.03 per cent dichlorobenzilate (akar), 0.02 per cent, parathion or 0.2 per cent sulphur effectively controls the pest.

Cotton like other crops is also susceptible to diseases like anthra-cones and black arm.

Anthracones (Colletrotrichum indicum, Dastur) locally known as Kawadi is a seed-borne disease of cotton, the sources of infection being infected seed and plant debris. It causes loss in bolls ranging from 2 to 5 per cent. In the seedling stage the disease causes 'seedling rot,' ' cotton rot' and damping off. Depressed circular spots appear on the bolls which become pinkish in the centre due to spore formation. Attack on the bolls results in short, immature and discoloured lint. The disease appears in the seedling stage in June-July and on bolls from October to November.

It can be controlled by adopting the following measures: (i) Destroying affected debris, (ii) Sowing healthy seeds, (iii) Treating the seeds with organo-mercurial compound containing 1 per cent organic mercury at the rate of two to three grams for one kilogram of seed.

Black Arm or Angular Leaf Spot (Xanthomonas malvacearum Smith Dawson) locally known as Tikka or Karpa mainly affects Indo-American variety as also irrigated cotton. It causes a loss in yield ranging from 2 to 10 per cent. It is a seed-borne disease the source of infection being affected seed. Infection is also caused by splashing rain drops carried by wind. It occurs on dry cotton from July to December and irrigated cotton from March to December.

The disease first manifests itself in the shape of small water soaked areas on leaves. These angular spots later coalesce involving larger areas of the leaf. When the disease extends along the edges of mild and lateral veins, the petioles, bolls and stems also get affected. This leads to the premature opening of the mature bolls. The lint from such bolls gets yellow strains and consequently its market value is reduced. Though indigenous varieties are not immune, the American varieties are highly susceptible to this disease.

The disease can be countered by adopting the following methods: (i) Growing resistant varieties, (ii) Using disease free or healthy seeds, (iii) Treating the seeds with organo-mercurial compound containing 1 per cent organic mercury, 3 to 4 grams for one kilogram of seed, (iv) Spraying the crop with bordeaux mixture 3:50, twice or thrice during the growing period of the crop.

Of Groundnut.

Aphids (Aphis crassivora) locally known as Mava is a serious pest of groundnut. The pest is of sporadic occurrence in most parts of the State. It frequently takes the form of an epidemic. By sucking the sap it reduces the vitality of the 'plants and acts as the vector of a serious virus disease commonly known as " Rosette " of groundnut.

The life history of this pest is not much different from that of safflower aphids, but the species become abundant during the kharif season. It can be controlled by spraying 10 per cent. BHC dust.

Tikka (Cercospora arachidicola, Hori) locally also known by the same name is a disease affecting groundnut which reduces the yield by 10 to 15 per cent. It is an air-borne disease the source of infection being infected plant debris. It occurs from August to October.

The disease is caused by two species of pathogen each producing characteristic spots. The first sign is the appearance of conspicuous round purplish brown spots on one and a half month old plants. These spots later on increase in size and become blackish in colour with the surface marked with concentric stromatic rings of conidiophores. The spots are surrounded by a bright yellow halo when mature.

It can be controlled by spraying the crop in the third week of July with 3:3:50 bordeaux mixture or any copper fungicide containing 50 per cent, metallic copper. A second spraying has to be given in the month of August and if still necessary a third one in the third week of September. Dusting with 200 to 300 mesh sulphur at the rate of 15 to 20 lbs per acre also gives good result.

Of Sesamum.

Sesamum Gall Fly (Aspondylia sesami) locally known as Tilavaril Pili or Kane is a minor pest affecting sesamum. So far no other host plants are known. The maggots get inside the young flower buds and the irritation causes gall formation which interferes with the process of pod formation. Consequently the buds wither away without bearing fruit.

The adult is like a small delicate mosquito. The larva is legless and remains inside the galls. Eggs are laid on flowers and the maggots develop into pupae after feeding on the contents of the flower. Pupae emerge as adults resembling mosquitoes.

Only preventive and not insecticidal measures of control have been devised so far. No stray plants should be allowed to grow in the off season so as to avoid giving rise to conditions favourable to the breeding of this pest. All infested buds should be scrupulously clipped and destroyed.

Shinx Moth (Acherontia styx) locally known as Pane Khanari Ali is another pest affecting sesamum. The caterpillar feeds extensively on leaves. The pest is found in all til growing areas of the State.

The moth is large with a dark grey bluish thorax. The abdomen is yellow with black bands. The fore-wings are dark brown. Full-fed larva is stout, 90 mm. long with a rough skin and having an anal horn at the abdominal end. It is light greenish in colour and has eight yellow stripes on its body. Eggs are laid singly on leaves. The larval period last for about two months. Pupation takes place in the soil, the pupae period lasting for about a month and a half.

As the caterpillar is very large hand-picking and destruction may be tried with effect. Dusting with 5 per cent BHC also gives good result.

Of Sugarcane.

Sugar-cane is susceptible to various pests, of which a few of the important ones are described below:

Sugar-cane stem Borer (Chilotrea infuscatellus, S.) locally known as Khod Kida is a pest which is known to affect only sugar-cane in Maharashtra State. However, in other states it is noticed on maize and bajra as well.

The pest is injurious principally to young cane. The caterpillars enter the plant from the side at ground level, by making holes in the stalk and may bore either downwards or up-wards or in both the directions. The presence of this pest is indicated by the drying up of the plant and causing of " dead hearts ". A dead heart can easily be pulled out.

The adult moth is greyish brown or straw-coloured measuring about 1½" when the wings are spread out. The lower wings are greyish white with the palpi pointed forward. Newly hatched larva is greyish with dark head and translucent body bearing spots and hair. Later these tiny spots develop into spines. Fully developed larva is greyish white in colour. Its body is often covered with dark marks, having tubercles and short setae on them.

Oval scale-like whitish eggs are laid overlapping each other on the under surface of leaves by the side of the midrib. The egg stage lasts for about three to five days. The newly hatched caterpillar enters the cane near the eye at ground level and later tunnels as far as the roots. Sometimes it migrates from the roots to other tillers. The larval stage lasts for about a month and before pupation it bores a round hole into the cane above ground level which is covered by a silken membrane from where the moth can escape. The pupal stage lasts for about a week and the entire life cycle gets over within a month and a half.

Among the control measures of this pest the following may be listed: (i) Uprooting the affected plants showing " dead hearts " ensuring that the larva has come out in the portion and feeding the same to cattle or burying them deep to prevent further development.

(ii) Planting in early November or December in case of plant cane and late planting in August or September in case of adsali cane will help in minimising the infestation, as the pest is less active during these months.

(iii) Releasing of Trichogamma parasites at the rate of one lakh of parasites per acre in three instalments at an interval of a fortnight in the infested field. This method, however, has not yielded satisfactory results, but its cheapness attracts much attention.

(iv) Light earthing up of the cane will prevent the emergence of the moth as the holes will get closed by the mud.

Sugarcane Top Shoot Borer (Scirpophaga nivella, F.) locally known as Shendyantil Ali is a very serious pest of sugarcane that breeds throughout the year and is capable of attacking cane at a later stage. The newly hatched caterpillar enters first the midrib of the leaf and bores downwards into the shoots from the top. As a result of such feeding the central shoot dries up in a characteristic way which later results in giving off side shoots, which form a bunch top. The punctures on the leaves, the death of the central shoots and the formation of bunch tops are the characteristic effects of this pest. In Maharashtra this pest affects only sugar-cane but in some other states jowar has been recorded as its host plant.

The moth is creamy white in colour with a wing span of a little over an inch when spread out. The females have orange hair-like structures at the tip of the abdomen. The first pair of wings of certain males has a single black spot on each wing. Fully developed caterpillars measure from about one to one and a half inches. They are yellowish white in colour.

Eggs in masses of 35 to 40 are laid on the undersurface of leaves and are covered with brownish hair-like structures. The newly hatched caterpillar after remaining for some time on the leaves enters the shoots. A fully developed larva measures one to one and a half inches and before pupation it prepares a silken membrane from which the moth can escape. The pupa is found in the larval tunnel. The egg stage lasts for six to. seven days. While the larval stage continues for three to six weeks, the pupal period lasts for seven to ten days. Within two to four days of its emergence the moth starts laying eggs.

Methods such as mass collection of eggs and destruction, removal of affected plants etc. are the only effective measures known so far.

Conservation of egg parasites with the help of special boxes can be tried. Chemical measures have, so far, not yielded any appreciable results. However, for effective control of the pest the following measures, are recommended: (i) Harvesting the crop by digging out the stump and not by cutting at the ground level as is usually done, (ii) Large scale campaign for collecting and destroying the egg masses of the top shoot borer, (iii) Giving two light earthings during the early stages of the crop.

Sugar-cane Leaf Hopper or Pyrilla (Pyrilla sp.) locally known as Tudtude is mainly a sugar-cane pest but sometimes its adults are found on maize and jowar. The nymphs and adult bugs suck the sap of cane leaves from the lower surface with the result that the leaves lose turgidity, begin to wither and ultimately dry up. The bugs secrete a honeydew like substance that spreads on the leaves on which a black fungus develops. As a result of pyrilla damage the sucrose content of the juice is reduced.

The adult pyrilla bug is a straw-coloured insect with two pairs of wings folded roof-wise on the back and the head extended like a pointed beak which is quite readily visible. The young nymphs that hatch out from the eggs are pale brown in colour having a pair of long characteristic processes covered by wax. They are very active and are found in large numbers on cane.

Pale greenish-yellow eggs are laid in clusters of 2 to 4 or 10 to 60 generally on the under surface of leaves, and between the detached leaf-sheaths and the stem. They are covered with white cottony waxy filaments and hatch out within a week. Within 50 to 60 days the nymphs become adult bugs. Egg laying continues from April to November and the period of the activity of the pest is from July to August.

The following control measures are suggested to overcome this pest: (i) Collection and destruction of egg masses. Crushing the eggs between fingers and the leaves has been found to be an easy and convenient method, (ii) Stripping off the lower leaves to remove the eggs laid in the leaf-sheaths was a method recommended for a long time. Now however, insecticides are used, (iii) Dusting the crop with 5 per cent. BHC at the rate of 30 to 40 lbs. and 50 to 60 lbs. per acre in the pre and post-monsoon periods respectively destroys both the nymphs and the adults. This method has largely been adopted now, (iv) Spraying 0.12 to 0.25 per cent. BHC or 0.25 per cent. D.D.T. at the rate of 30 to 50 gallons per acre for young cane during the pre-monsoon period and over 100 gallons during the post-monsoon period also gives considerable relief.

Of Chillis.

Fruit Rot (Colletotrichum capsoci) (Syd.) is locally known as Kavadi and affects both dry and irrigated chilli crop during November and December. There is rotting of fruit and fruit drop resulting in a loss of nearly 15 to 20 per cent, in the yield. Plant debris and the infected seeds are the sources of the incidence of the disease. Seed treatment with organo-mercurial fungicides and spraying three times with bordeaux mixture 3: 3: 50 or any other copper fungicide from flowering onwards help in reducing the disease.

Of Grapes.

Powdery Mildew [Uncinula necator (Schew.) Burr.] locally known as Bhuri is an air-borne grape disease, the source of infection being spores carried by wind from diseased to healthy crops. In severe cases it causes a 10 to 15 per cent, loss in the yield. No variety of grapes is immune to this disease.

The disease manifests itself in the form of whitish patches appearing on both sides of the leaves. These patches gradually enlarge covering maximum part of lamina turning whitish green. In severe cases withering and shedding of leaves, giving wilted appearance to the plant takes place. Patches also appear near the base of the shoots which turn black. Affected blossoms are rendered incapable of developing fruits. Young berries, if affected in the early stage, drop and in advanced stage they crack. The disease occurs from November to January.

Powdery Mildew can be effectively controlled by dusting the crop with sulphur of 200 to 300 mesh, in the third weeks of November, December and January.

Anthracnose (Gloeosporium ampelophagum, Sace) locally known as Karpa is another air-borne disease of grapes, the source being infected debris. In case of a severe attack the vines are considerably damaged resulting in a loss in yield ranging from 20 to 30 per cent.

The disease appears on the vine stems and young shoots in the form of deep seated elongated lesion, dark on the border and pinkish white in the centre. Similar spots also develop on leaves. Young blossoms when affected, show blighting effects. If, however, the crop is affected in the advanced stage, berries show a peculiar symptom known as blind eye spot. The disease affects the crop from June to November. It can be controlled by spraying with bordeaux mixture 5: 5: 50 in the third week of May and October and last week of July and November.

Downy Mildew (Plasmopara viticola (Berk and Curt) Berl and DeToni) locally known as Kevada is yet another air-borne disease of grapes. Like the Karpa, its source of infection is also infected debris and it causes a loss of nearly 20 to 30 per cent, in the yield in case of a severe attack.

The disease attacks all aerial plant parts viz., leaves, canes, tendrils, bunches etc. On the upper surface the disease makes its appearance in the form of greenish yellow indefinite sized spots which look translucent and oily. Under humid conditions white downy growth is found on the under surface of the leaves. The leaves finally dry up and turn brown. Badly affected leaves fall down. On tender bunches shrivelling, hardening and mummification is observed. However, matured berries do not succumb to the disease. The disease affects the crop from June to September. It can be controlled by spraying with bordeaux mixture 5: 5: 50 in the third week of May and October and last week of July and November.

Of Mango.

Powdery Mildew of Mango (Oildium magnifarae, Herthet) locally known as Ambyavaril Bhuri is an air-borne disease of mango crop, the infection being carried by wind and hoppers Idiocerus Sp. The loss in yield in case of a severe attack amounts to nearly 30 per cent.

Whitish Coating appears on the inflorescence covering it entirely. This coating later turns black and consists mainly of spores and mycelium of the fungus. Young fruits are also sometimes thus affected. The incidence of this disease is from January to February and it can be controlled by dusting the tree with sulphur (200 mesh) plus D. D. T. (4: 1) as soon as the tree blossoms.

Disease of citrus fruits.

Citrus Canker (Xanthomonas citri) locally known as Devi Rog chiefly affects lime disfiguring the fruits and thus reducing its market value considerably. All aerial plant parts are affected on which a canker in the form of raised corky spots, orange to brownish in colour, appears.

These spots are more conspicuous on leaves and fruits and cause disfiguring. The disease persists from April onwards and can be controlled by pruning the heavily infected twigs and spraying the plants with 5: 5: 50 bordeaux mixture.

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