Transgenic Cry1Ac cotton does not affect the development and fecundity of Chrysoperla carnea

Realized heritability, inheritance, and mechanism of chlorfenapyr resistance in biocontrol agent, Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae): A step towards sustainable pest management

A field population of Chrysoperla carnea was exposed for 17 generations to chlorfenapyr insecticide that resulted in 217-fold resistance compared to a susceptible strain. The overlapping of LC50 values in reciprocal crosses and their dominance values indicated that chlorfenapyr resistance was autosomal and incompletely dominant. The chi-square analysis of back-cross mortality confirmed the polygenic nature of chlorfenapyr resistance. The results of effective dominance of chlorfenapyr resistance indicated that resistance at the highest concentration was completely recessive. The realized heritability of chlorfenapyr resistance in the first 9, last 9, and a total of 18 generations was 0.28, 0.42, and 0.31, respectively. Furthermore, synergism results showed that both experimental synergists, PBO and DEF, did not synergize the toxicity of chlorfenapyr. In conclusion, C. carnea had been found to have autosomal, partially dominant, and polygenic chlorfenapyr resistance. Meaning that thereby resistance is inherited through multiple genes and is not limited to a single gene or sex-linked trait. These findings will help to develop an effective IPM model focusing on the simultaneous use of selective insecticides and resistant biocontrol agents to reduce the problem of resistance development in pest populations.

Impact of transgenic insect-resistant maize HGK60 with Cry1Ah gene on community components and biodiversity of arthropods in the fields

In recent years, transgenic technology has developed rapidly, but the risk of the environmental release of transgenic organisms is still a key issue. Research on the impact on biodiversity is an effective way to objectively evaluate the risk. By taking transgenic maize HGK60 with insect-resistant gene Cry1Ah and common maize Zheng 58 as control, a 2-year experiment of arthropod community biodiversity in fields of them were studied using three methods.in 2019 and 2020. The results showed that a total of 124 species and 38537 individuals were observed from the experiment, belonging to 11 orders and 40 families. There was no significant difference in the individual number and species number of herbivorous, predatory and parasitic groups in the two kinds of maize in two years. Only the individual number of HGK60 was significantly higher than that of common maize Zheng 58 at heading stage in 2019. And the percentages of individual number and species number in different groups were basically the same in the two kinds of maize at each stage in two years. Analyses of Richness index, Shannon-Wiener diversity index, Dominance index and Evenness index showed no significant difference between the two kinds of maize in two years. The similarity coefficient of the arthropod community suggested that the arthropod community composition of HGK60 was similar to that of common maize Zheng 58. Furthermore, HGK60 had no significant effect on the relative stability of the arthropod community. These results indicated that despite the presence of a relatively minor difference in arthropod community between the two kinds of maize, the planting of HGK60 had little effect on arthropod community biodiversity. The results provided some data and support for the further studies of environmental risk of transgenic crops.

Transgenic Cry1Ac/CpTI cotton assessment finds no detrimental effects on the insect predator Chrysoperla sinica

The widespread commercialization of genetically modified (GM) cotton makes it important to assess the potential impact of this recombinant crop on non-target organisms. As important natural enemies of cotton field predators, green lacewing Chrysoperla sinica larvae are exposed to Bt insecticidal proteins expressed by GM cotton by feeding on herbivorous pests, and adults are directly exposed to Bt proteins by cotton pollen consumption. However, potential impacts of transgenic Bt cotton on C. sinica remain unclear. In this study, we evaluated the effects of two transgenic cotton varieties, CCRI41 and CCRI45, which express Cry1Ac (Bt toxin) and CpTI (Cowpea Trypsin Inhibitor), on C. sinica larvae and adults. After being fed with cotton aphids Aphis gossypii reared on transgenic cotton, the survival rate, developmental duration, pupation rate, and emergence rate of larvae were not adversely affected. After being fed two types of transgenic cotton pollen, the 7-day weight of adults and the preoviposition period and the cumulative oviposition of females were not significantly different from control specimen. Taken together, these results indicate that the potential risks of the two tested GM cotton varieties for the predator C. sinica are negligible. CAPSULE: Our study indicated that GM cotton varieties CCRI41 and CCRI45 have no adverse effects on insect predator C. sinica.