Innovative strategy involving judicious pesticide management to control pests of sorghum in India

Sorghum bieolor (L.) Moench. is the third important cereal crop after rice and wheat in India. It is heavily ravaged by a number of key pests. At present, the sorghum shootfly, Atherigona soccata (Rondani); stem borer, Chilo partellus (Swinhoe); sorghum midge, Contarinia sorghieola (Coquillet); and sorghum earhead bug, Caloeoris angustatus Lethiery are key pests of sorghum which either individually or collectively serionsly limit the productivity of newly developed cultivars. The main thrust in the control of these key pests and other pests was directed towards the use of insecticides. A large number of insecticides belonging to different groups starting from chlorinated hydrocarbons to synthetic pyrethroids were used against these pests in different formulations (dust, spray, granules, etc.) with different modes of applications, viz., seed treatment, soil furrow application at sowing, side-dressing after crop emergence, foliar sprays and dusts, leaf whorf placement of granules, dusts and sprays, etc. Some of the insecticides used for their control are DDT, BHC, lindane, endrin, phorate, trithion, parathion, dimethoate, phenthoate, phendol, carbaryl, monocrotophos, malathion, endosulfan, cytrolane, carbofuran, aldicarb, mephosfolan, disulfoton, sevimol, diazinon, fenitrothion, ehlorphyrifos, cypermethrin, permethrin, fenvalerate, ehlorfenvinphos, etc. These included even outdated insecticides, though earlier spectaeular suceess was achieved. Complete relianee on insectieides due to their broad speetrum biological activity and associated risks cireumvents their use. This situation has led to develop integrated pest management strategies in sorghum where each control component has to play an important role. Quantities of insecticides can be reduced to economic level by integrating their use with resistant varieties like P 311, SPV 1015, P 37, P151, E 601, biocontrol agents and cultural practices. Determination of economic thresholds for different key pests is desirable both to realize maximum benefit of chemieal eontrol and to reduce the number of applications. Seed treatment with earbofuran (5 parts of a.i/100 parts of seed) resulted in suecessful control of shoottly. Two applications of endosulfan (4% dust) at 5.0 and 7.5 kg/ha used 25 and 35 days after germination were effective as also more economieal than those applied 20, 30 and 40 days after germination in controlling the stem borer. With this schedule, the rate of application of endosulfan was reduced to 12.5 kg/ha from 22.5 kg/ha of commercial formulation. Foliar and earhead pests were successfully controlled by applying 1 litre of endosulfan in 500 to 600 Iitres of water at 50% flowering as foliar and earhead spray. Application of inseeticides at vulnerable stage of pests helps in reducing the quantity of insecticides and effectively checking the pests. Hazards of pollution, residues and effects on non-target organisms can also be avoided. Thus, the hitherto misuse or overuse of insecticides will not only be checked but will also effectively halt the ever increase of various problems associated with pesticides. In future, control programmes in sorghum with proper and judicious pesticide management should provide the solution to intricate and complex problems of this crop.