Submitted to: Chinese Journal of Biological Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/20/2006
Publication Date: 4/16/2007
Citation: Sun, L., Zhao, L., Guo, J., Li, B. 2006. Effects of Ttmperature on the development rate of Conitus steveni, a potential biocontrol agent for saltcedar in the United States. Chinese Journal of Biological Control. 22(3):186-189. Interpretive Summary: The small tree or shrub, saltcedar (in plant genus Tamarix) was introduced from Asia and the Mediterranean area into the western U.S. in 1820s, where it has invaded riverbottoms and lakeshores. It causes great damage to native and rangeland ecosystems in the U.S. and northern Mexico by displacing native plant communities, degrading wildlife and fish habitat, using great quantities of scarce groundwater, and increasing soil salinity and wildfires. As part of a program on biological control of saltcedar in the U.S., the authors measured the developmental rate of each life stage at 5 constant temperatures in the laboratory and then calculated the theoretical threshold for development and the degree-days for development of each life stage and the theoretical number of generations during the year. This information is useful in calculating the expected rate of control of saltcedar if this weevil were released in the U.S. and to compare actual U.S. rate with that in China to discover if some mortality factors in the U.S. might be suppressing the rate of control.
Technical Abstract: The effects of temperature on development of Coniatus steveni (Curculionidae, Coleoptera) were studied under a range of constant temperatures (17 C, 20 C, 24 C and 32 C) in the laboratory. The relationships between temperatures and development rate of each life stage were fitted with linear models. The development threshold temperatures for egg, larva, pre-pupa, pupa, pre-oviposition adult, and whole generation were 13.48, 12.48, 10.32, 13.28, 8.71 and 11.44 C, respectively. The effective degree days for the development of each life stage were 46.52 for egg, 12.52 for larva, 31.70 for prepupa, 62.17 for pupa, 186.19 for pre-ovipositional adult, and 445.78 for whole generation from egg to pre-ovipositional adult. And theoretical number of generations was estimated as 3.24.