Response to short-term cold storage for eggs of agasicles hygrophila (coleoptera: Chrysomelidae), a biological control agent of alligator weed alternanthera philoxeroides (caryophyllales: Amaranthaceae)

The alligator weed flea beetle, Agasicles hygrophila Selman & Vogt (Coleoptera: Chrysomelidae) has been used very successfully for the biological control of the widely-distributed invasive weed Alternanthera philoxeroides (Mart.) Griseb (Caryophyllales: Amaranthaceae). In order to extend the 'shelf life' of natural enemies released in biological control programs, cold storage has proven to be a valuable commercial procedure. To determine a suitable low temperature for storage of A. hygrophila, we conducted short-term cold storage treatments of eggs (4°C for 0.5, 1, 2, 5 d, and 7.5, 10, 15°C for 5 d and a control of 25°C; all eggs were returned to 25°C after the treatments). We evaluated the effects of these treatments on the subsequent fitness of the populations based on a demographic analysis using group-reared age-stage two-sex life tables. For 5 d storage, temperatures below 10°C had lethal effects, which were also observed at 4°C for 2 d storage. Storage at 4°C for 0.5 d did not affect the fitness of A. hygrophila, but it did not prolong the developmental time. Storage at 10°C for 5 d significantly decreased rates of population increase compared with 25°C. A. hygrophila stored at 15°C for 5 d had similar age-(stage) specific survival rates, rates of population increase, increased longevity and reproductive capability to the controls at 25°C. It is concluded that there were no significant fitness costs after 5 d storage at 15°C, which is therefore potentially a suitable storage temperature for A. hygrophila eggs. © The Author(s) 2018. Published by Oxford University Press on behalf of Entomological Society of America.National Natural Science Foundation of ChinaWe sincerely thank Dr. Lingling Gao (CSIRO Plant Industry, Perth, Australia) for reviewing an early version of this manuscript and the staff in the Biosafety and Biocontrol Group, Shanxi Agricultural University at Taigu, Shanxi, China. This work was supported by the National Natural Science Foundation of China (31570436 and 31500304). Y.H.L. and R.Y.M. conceived and designed the experiments. Y.H.L., D.J., X.F.Y., and Y.X.W. performed the experiments. Y.H.L. and H.C. analyzed the data. Y.H.L., T.J.R-S., H.C., and R.Y.M. wrote the paper. We declare no competing financial interests

Host plant resistance and insect pest management in chickpea

The major pest problems in chickpea, i.e. pod borers (Helicoverpa armigera and H. punctigera), leafminer Liriomyza cicerina, black cutworm Agrotis ipsilon, aphids (Aphis craccivora), semilooper Autographa nigrisigna and bruchids (Callosobruchus spp.), and their management options (cultural, biological and chemical controls) are discussed. Low to moderate levels of resistance have been identified in the germplasm, and a few improved cultivars with resistance to pod borer and high grain yield have been developed. Germplasm accessions of the wild relatives of chickpea (Cicer bijugum, C. judaicum and C. reticulatum) can be used to increase the levels and diversify the bases of resistance to H. armigera. Efforts are also underway to utilize molecular techniques to increase the levels of resistance to pod borer. Synthetic insecticides, agronomic practices, nuclear polyhedrosis virus, entomopathogenic fungi, bacteria and natural plant products have been evaluated as components of pest management in chickpea