omb3dyw

ENVIRONMENTAL IMPACTS : PEST DYNAMICS INCLUDING RESISTANCEAmreli population was only slightly less susceptible than the most susceptiblepopulation. The data reported here constitute the first evidence of field-evolvedresistance of pink bollworm to Cry1Ac. This initial evidence spurred more extensiveevaluations during the 2009–2010 growing season, which confirmed field-evolvedresistance to Cry1Ac in Amreli. The lack of cross-resistance to Cry2Ab2 suggeststhat plants producing this toxin are likely to be more effective against resistantpopulations than plants producing only Cry1Ac.7. Storer NP, Babcock JM, Schlenz M, Meade T, Thompson GD, Bing JW andHuckaba RM (2010) : Discovery and characterization of field resistance toBt maize: Spodoptera frugiperda (Lepidoptera: Noctuidae) in Puerto Rico.J Econ Entomol.103(4) : 1031-8.Transgenic maize, Zea mays L., event TC1507 produces the Cry1F protein toprovide protection from feeding by several important lepidopteran pests, includingSpodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae). Reports of reducedfield performance against this species in Puerto Rico were investigated, andlaboratory bioassays showed that S. frugiperda collected from the affected areaexhibited lower sensitivity to the Cry1F protein compared with typical coloniesfrom other regions. The resistance was shown to be autosomally inherited andhighly recessive. The Puerto Rico colony was shown to be moderately lesssensitive than susceptible laboratory strains to Cry1Ab and Cry1Ac, but thedifferences in sensitivity were dramatically smaller than for Cry1F. Potentialcontributory factors to the emergence of resistance to Cry1F in Puerto Ricopopulations of S. frugiperda include the tropical island geography, unusually largepopulation sizes in 2006, and drought conditions reducing the availability ofalternative hosts. In response to this resistance incident, the technology providershave stopped commercial sales of TC1507 maize in Puerto Rico pending potentialreversion to susceptibility.8. Lu Y, Wu K, Jiang Y, Xia B, Li P, Feng H, Wyckhuys KA, Guo Y (2010) : Miridbug outbreaks in multiple crops correlated with wide-scale adoption of Btcotton in China. Science. 328(5982) :1151-4.Long-term ecological effects of transgenic Bacillus thuringiensis (Bt) crops onnontarget pests have received limited attention, more so in diverse small holderbasedcropping systems of the developing world. Field trials conducted over 10years in northern China show that mirid bugs (Heteroptera: Miridae) haveprogressively increased population sizes and acquired pest status in cotton andmultiple other crops, in association with a regional increase in Bt cotton adoption.More specifically, our analyses show that Bt cotton has become a source of miridbugs and that their population increases are related to drops in insecticide use inthis crop. Hence, alterations of pest management regimes in Bt cotton could beresponsible for the appearance and subsequent spread of nontarget pests at anagro-landscape level.(127)