| evaluation of the natural refuge function for helicoverpa arnigera (lepidoptera: noctuidae) within bacillus thuringiensis transgenic cotton growing areas in north china. | the density of helicoverpa armigera (hübner) populations on bacillus thuringiensis berliner (bt) transgenic cotton, corn, peanut, and soybean; differences in its development on bt cotton and common (nontransgenic) cotton; and the potential for mating among populations from bt cotton fields and other crop fields were investigated in the suburbs of xinxiang city (henan province) and langfang city (hebei province) in the southern and northern parts of north china, respectively. although development ... | 2002 | 12216828 |
| northward migration of helicoverpa armigera (lepidoptera: noctuidae) and other moths in early summer observed with radar in northern china. | the northward migration of helicoverpa armigera (hübner) and other moths in early summer was observed with radar in 2001 and 2002 at langfang, hebei province, china. migratory flights typically occurred at heights up to 1.2 km above ground level (agl), and high density layer concentrations frequently formed at 200-300 m agl. adult moths of local populations took off at dusk and ceased flight approximately 0.5 h before sunrise with area density peaking approximately 35 min after dusk. a strong du ... | 2004 | 15666739 |
| return migration of helicoverpa armigera (lepidoptera: noctuidae) during autumn in northern china. | the autumn migration of helicoverpa armigera (hübner) was observed with radar and two types of light-trap at langfang, hebei province, china in 2001 and 2002. the sudden increase in the proportion of h. armigera moths in the searchlight trap indicated migration into the area and catches increased 10-fold during the second half of the night due to the landing of migrants before dawn. the moths' migratory flights took place at up to 2000 m above the ground, and moths flew differentially at times, ... | 2005 | 16048684 |
| resistance allele frequency to bt cotton in field populations of helicoverpa armigera (lepidoptera: noctuidae) in china. | resistance evolution in target insects to bacillus thurningiensis (bt) cotton, gossypium hirsutum l., is a main threat to bt cotton technology. an increasing trend of population density of helicoverpa armigera (hübner) (lepidoptera: noctuidae) has been observed since 2001 in qiuxian county (hebei, china), where bt cotton has been planted dominantly since 1998. this region was selected in 2006 and 2007 for estimating frequency of gene alleles conferring resistance to bt cotton by screening the f1 ... | 2008 | 18613597 |
| cry2ab tolerance response of helicoverpa armigera (lepidoptera: noctuidae) populations from crylac cotton planting region. | helicoverpa armigera (hübner) (lepidoptera: noctuidae) is an important lepidopteran pest of cotton, gossypium hirsutum l., in asia. transgenic cotton expressing the cry1ac gene from bacillus thuringiensis (bt) has been widely planted for control of this pest. for managing the potential risk from resistance evolution in this pest, a new transgenic bt cotton containing cry1ac and cry2ab genes (gene pyramided strategy) was designed as a successor of cry1ac cotton. this article reports on levels of ... | 2009 | 19610441 |
| frequency of bt resistance alleles in h. armigera during 2006-2008 in northern china. | helicoverpa armigera is an important lepidopteran pest of cotton in china. from 2002, the frequency of bt resistance alleles and quantitative shifts in larval cry1ac tolerance of field h. armigera population were monitored using bioassays of f(1) and f(2) offspring of isofemale lines from xiajin county of shandong province (an intensive bt cotton planting area) and anci county of hebei province (a multiple-crop system including corn, soybean, peanut, and bt cotton) in northern china. during 2006 ... | 2009 | 19689916 |
| evidence of field-evolved resistance to cry1ac-expressing bt cotton in helicoverpa armigera (lepidoptera: noctuidae) in northern china. | evolution of resistance threatens the continued success of transgenic crops expressing insecticidal proteins. one of the key factors for successful resistance management is the timely implementation of monitoring programmes to detect early changes of resistance allele frequency in field populations. f(1)/f(2) screen, dose-response bioassays and field survey were used to monitor resistance to the cry1ac-expressing cotton in a field population of helicoverpa armigera (hübner), the primary target o ... | 2010 | 19764057 |