Vol.12_No.2 - Pesticide Alternatives Lab - Michigan State University
Vol.12_No.2 - Pesticide Alternatives Lab - Michigan State University
Vol.12_No.2 - Pesticide Alternatives Lab - Michigan State University
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
Spring 2003 Resistant Pest Management Newsletter Vol. 12, <strong>No.2</strong>followed by population from Nalgonda (9.13 µg/µL),Guntur (8.73), Mysore (5.15), and Dharwad (4.84). Thelowest LD50 value was observed in the populationfrom Madurai (0.78µg/µL) followed by Kovilpatti(0.87), Coimbatore (1.35), and Madhira (1.12). Theresistance ratio (RR) against the ICRISAT susceptiblestrain was found to be highest for the population ofRaichur (66.8 fold) followed by Nalgonda (45.7),Guntur (43.6), Mysore (25.8), Dharwad (24.2), Nagpur(14.6), and Nanded (10.7). The least resistance ratiowas observed in the population of Madurai (3.9)followed by Kovilpatti and Madhira (Table 6).The general LD50 values recorded were far highercompared to the recommended dosages indicating theexistence of resistance as was reported earlier (Armeset al., 1992). However, the resistance drastically differsfrom location to location within the South Indiancotton ecosystems. The resistance levels in the Guntur,Nalgonda, and Raichur regions (heavy insecticideusage areas) are due to heavy dependence oninsecticides. This clearly explained that resistancelevels were proportionate with the usage of pesticides.The study conducted by Forrester (1990) also clearlyrevealed that resistance levels rose when pyrethroidswere used but fell significantly when they werewithheld. Thus, the pesticides were creating very highselection pressure for resistant genotypes. Thissuggests that indiscriminate use and heavy dependenceon pesticide will further complicate the alreadyworsened situation and hints at aiming for insecticideresistance management strategies.ACKNOWLEDGEMENT: We thank Dr. Daniel R. Zeigler,Ohio <strong>State</strong> <strong>University</strong>, US for providing the Cry1Acover expressing clone. This research work wassupported by the DBT, GOI project grants to BF.Thanks are also due to Dept. of Agril. Entomology,UAS Dharwad for providing infrastructure facilitiesand all those scientists who helped us during the visitto different locations across south India for H.armigera collection. We thank Dr. G.T.Gujar, IARI,New Delhi, for his useful suggestions during the studyand encouragement.REFERENCES:KRANTHI.K.R., JADHAV,D.R., WANJARI,R.R., SHAKHIR ALI,S.AND RUSSEL,D., 2001, Carbamate and organophosphateresistance in cotton pests in India. Bull.Ent. Res., 91:37-46.Mc CAFFEREY, A.R., KING, A.B.S., WALKER, A.J. AND EL-NAYIR, H., 1989, Pestic.Sci., 27:65-76.RAKILA, A. AND PADMANABHAN, N.R., 1995,Knowledge andfactor influencing pesticide use and frequency of plant protectionmeasures. Pestology, 19:9-12. ROSS, G.J.S., 1987,Maximumlikelihood programme. The Numerical Algorithm groupRothemsted Experimental Station, Harpendon,U.K.ARMES, N.J., JADHAV, D.R., BOND, G.R. AND KING, A.B.S., 1992,Insecticides resistance in Helicoverpa armigera in South India.Pestic Sci., 34:335-364.FORRESTER, N.W., 1990, Designing, Implementing and Servicing anInsecticide resistance Management Strategy. Pestic sci., 28:167-179.B. Fakrudin*, Badariprasad, K. B. Krishnareddy, S. H.Prakash, Vijaykumar, B.V. Patil#, & M. S.KuruvinashettiDepartment of Biotechnology<strong>University</strong> of Agricultural Sciences DharwadKrishinagar, Dharwad - 580005, KarnatakaIndia#Professor and HeadDept. of Agricultural EntomologyCollege of AgricultureRaichur - 584101, KarnatakaIndia*CorrespondenceDevelopment of Resistance in Insects to Transgenic Plants with Bacillus thuringiensis Genes: Current Status andManagement StrategiesINTRODUCTION There is a continuing need to increasefood production as the world population is expected toexceed 6 billion by 2050. In both the developed andundeveloped countries, the cost for achievingproduction has become too high because of the need toincur costs for controlling insect pests that cause anestimated loss of $10 billion annually. The difficultiesexperienced in controlling insect pests over the past 30years have been largely due to the over-use ofpesticides. Indiscriminate use of insecticides has ledboth to the development of resistance in insects and thedestruction of natural enemies. Bio-pesticides such asBt (Bacillus thuringiensis) products are widelyregarded as being the least harmful to natural enemies.Because of its selectivity and environmental safety,usage of Bt is increasing, particularly in IPM programs.Foliar application of Bt breaks down quickly underfield conditions due to UV sensitivity and rainfall.With the advent of recombinant DNA technologies,insecticidal proteins present in Bt have been expressedin crop plants to ensure durable insect resistance. Thereis a considerable increase in global area undertransgenic crops from 1.7 million hectares in 1996 to52.6 million hectares in 2001, in which the share of Btcrops was 15% of the total area (James 2001).Although much progress has been made in thediscovery of new genes for introduction into plants,only Bt genes have been exploited so far.Considerable efforts have been made toincorporate delta-endotoxins from Bt into cereals, rootcrops, leafy vegetables, forage crops, and horticulturalcrops (Schuler et al. 1998). Of the $8.1 billion (US16