Spring 2003 Resistant Pest Management Newsletter Vol. 12, <strong>No.2</strong>farmers, 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
Spring 2003 Resistant Pest Management Newsletter Vol. 12, <strong>No.2</strong>credit. The dealers profited from usingthe illiteracy of the farmers, and the lackof a good extension services in many ofthe remote rural areas also aggravatedthe problem. Prolonged use of the sameinsecticides will definitely elevate theproblem of insecticide resistance, as hadhappened in Andhra Pradesh andKarnataka during late 1980s and early1990s (1).Identification of insecticide usagepatterns allows for the rotation ofinsecticides and the rational use ofpesticides for the better management ofthe pest and for insecticide resistance (4,7). This study brings to light that farmerknowledge about insecticide usage isvery poor and as such, insecticides arebeing used indiscriminately by thefarmers were aware of and used Bt for the control ofbollworm on cotton.Monocrotophos was the single most commoninsecticide used in all of the locations of South Indiafor the control of cotton bollworm. In all of the regionsexcept Kovilpatti and Nalagonda, monocrotophos andquinolphos were the primary choices, by more than 30percent, of insecticides for use in controlling bollworm.Both the relative prevalence and the use of insecticidesvaried across the geographical locations of South India(Table 2).It was very clear from the survey that the majorityof the farmers were greatly influenced by the dealers.Beside the fact that the pesticide dealers had such animpact on the pesticide use pattern among farmers, thefarmers tended to be more loyal to those dealers whoalso provided technical advice in all aspects of plantprotection. These results were in line with those ofRakila and Padmanaban (6). The main reason for thisdependence appeared to be that most farmers wereeconomically poor and depended on the dealers forfarmers of South Indian cotton ecosystems. Theexceptions are the regions of Raichur and a few regionsof Andhra Pradesh, which suffered severe outbreaks inthe past. Perhaps the extensive extension efforts withrespect to insecticide usage in these regions areresponsible for the better knowledge of the farmers (7).In order to rationalize the pesticide use on the farms, itis imperative to stress the importance of economicthreshold levels in the application of pesticides and tofollow the integrated pest management practices tobring down the expenditure and to increase theeffectiveness of plant protection measures in cotton.Further, the outcome of the survey clearly indicates theneed for genetic investigations of the geographicpopulations of bollworm and the formulation ofpopulation specific integrated pest management (IPM)modules. Based on the genetic similarity and theinsecticide composition patter by different geographicpopulations, we need to force the rotation of modulesfor the better management of cotton bollworm andinsecticide resistance. Concomitantly, there is a greater37
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