Vol.12_No.2 - Pesticide Alternatives Lab - Michigan State University

Spring 2003 Resistant Pest Management Newsletter Vol. 12, No.2farmers, which has been traced to insecticide resistancein H. armigera (3).The consumption pattern of different insecticidesbelonging to different groups varies across thegeographic locations primarily based on the dealerrecommendations, intensity of pests and diseases,influence of peer groups, efficacy of particularinsecticides, knowledge level of the farmer, availabilityof a particular insecticide, and socioeconomicconditions of the farmer (4). Though a number ofstudies were conducted on knowledge and pesticideuse, the changing scenario warrants more studies. Inview of this, to determine the relative predominance ofindividual insecticide molecules and their relativeusage over the South Indian cotton ecosystem, a surveywas undertaken during the 2000-2001 cropping season.We selected four South Indian states viz.,Maharastra, Andhra Pradesh, Karnataka, and TamilNadu, which comprise more than 95 percent of thecotton cultivation in South India. Looking into thedistribution of cotton cultivation, three samplinglocations in each state were selected to collect the data.The locations selected included: Nagpur, ParbhaniNanded (Maharastra), Guntur, Madhira, Kovilpatti(Andhra Pradesh), Raichur, Dharwad, Mysore(Karnataka), Coimbatore, Madurai, and Kovilpatti(Tamil Nadu). During the cropping season, eachlocation was visited and interacted with by at least 25farmers with a schedule on various aspects of insectpest control including insecticide usage pattern.Aspects concerning insecticides being used, dosage perapplication, number of insecticide applications percrop, number of times a particular insecticide was used,and the relative efficacy in farmers' perception etc.,were collected. Wherever possible, fields were visitedand actual prevalence of cotton bollworm was studied.Later, information on number of insecticides, relativeusage in terms of number of sprays, concentration,farmer perception, and attitude, etc., were computed foreach location and overall cotton ecosystem of SouthIndia.Overall, in the South Indian cotton ecosystem, asmany as 15 different insecticides: monocrotophos,quinolphos, chlorpyriphos, cypermethrin, decamethrin,acephate, endosulfan, fenvelarate, polytrin, sumicidine,carbaryl, permethrin, avaunt, Bacillus thurengenesis(Bt), and spinosad were used with the specificobjective of controlling cotton bollworm. Amongchemical insecticides, monocrotophos was the mostextensively used insecticide with a share of 26.8percent of all the insecticides, followed bychlorpyriphos (19.9%), quinolphos (18.8%),cypermethrin (14.93%), and endosulfan (12.53%)(Figure 1). Bt was the only biological agentencountered in the whole ecosystem and accounted for0.76% overall. However, it was used only in theRaichur region of Karnataka state where it forms9.09% of all the insecticides used in the region.Similarly, spinosad (a recent chemical in South Indiawhich is not yet recommended and commerciallyavailable in market), permethrin, and polytrincomprised 0.36%, 0.46%, and 0.76% respectivelyoverall in the ecosystem but were used only inCoimbatore (4.34%), Nalagonda (5.55%), and Nanded(9.09%) respectively (Table 1). The number ofinsecticides being used to control bollworm variedacross locations in South India. A maximum of 8insecticides including 1biological agent were recordedin the Raichur region followed by 7 in Nalagonda,Coimbatore, and Kovilpatti. Farmers in the Mysoreregion used 4 different insecticides, which was the leastnumber in the overall ecosystem. Raichur is knownhistorically for being the cotton city of India and for itshigh intensity use of insecticides in Asia. Apart fromusing the maximum number of insecticides, Raichurrecorded up to 25 sprays to control the bollworm in thepresent study. Most of the cotton regions of northernstates of South India used between 18-20 sprays, whileDharwad and Mysore used fewer (8-12 and 10-12)numbers of applications of insecticides in the region(Table 1). In all of the locations the usage ofinsecticides was erratic and indiscriminate. Overall, 60-75% of the farmers applied the insecticides as mixtureof 3 to 6 in an interval of 2-3 days during the criticalperiod. Armes et al (5) reported similar insecticideusage patterns in Karnataka and Andhra Pradesh forthe control of H. armigera. Generally, only the firsttwo sprays were not mixtures of insecticides, andmonocrotophos was always used throughout SouthIndia without exception. However, only 21.23% ofcotton farmers of the Raichur region used theinsecticides as a mixture. It was interesting to note that78.77% of the farmers in this area used a definiteschedule of insecticides for the control of cottonbollworm. Most of the farmers in this region rotatedthe insecticides. Further, this was only region where36