Studies on development rate of Diabrotica barberi
Laboratory studies were carried out in USA to determine the development rates and thresholds of immature stages of Diabrotica barberi (EPPO A1 quarantine pest), over a wide range of constant temperatures (15, 18, 21, 24, 27, 30, 31.5 °C). Laboratories methods used to maintain the insects at their various stages were similar to those used in previous studies on Diabrotica virgifera virgifera (EPPO A2 quarantine pest) done by Jackson and Elliott (1988), to facilitate comparison. Results showed that development from egg to adult was completed at all temperatures, but survival was lower at 15 and
31.5 °C for both males and females. Optimal temperature for growth lies between 18 and 30 °C. The proportion of time spent in each life stage from hatch to adult emergence is independent of sex and was respectively: 15 % for 1st instar, 18 % for 2nd instar, 41 % for 3rd instar and 25 % for pupal stage ; this is similar to data obtained for D. virgifera virgifera. Nevertheless, development time between males and females is substantially different, males seem to emerge earlier than females. A developmental threshold of 10.2 °C was established for development from hatch to adult emergence. Development from hatch to adult emergence was faster at 30 °C (28 d) and slowest at 15 °C (98 d). Accumulated degree-days (base 10.2 °C) is »525 DD from hatch to adult escape (434 DD was observed for D. virgifera virgifera). By adding data provided by other studies for the egg stage, it would take »865 DD for adult to emerge in the field. This number is approximately 150 DD shorter than what was found by other authors to obtain adult emergence in the field under fluctuating temperatures. The authors concluded that these data could serve as a basis for prediction models to be used for a better timing of chemical treatments against D. barberi.
31.5 °C for both males and females. Optimal temperature for growth lies between 18 and 30 °C. The proportion of time spent in each life stage from hatch to adult emergence is independent of sex and was respectively: 15 % for 1st instar, 18 % for 2nd instar, 41 % for 3rd instar and 25 % for pupal stage ; this is similar to data obtained for D. virgifera virgifera. Nevertheless, development time between males and females is substantially different, males seem to emerge earlier than females. A developmental threshold of 10.2 °C was established for development from hatch to adult emergence. Development from hatch to adult emergence was faster at 30 °C (28 d) and slowest at 15 °C (98 d). Accumulated degree-days (base 10.2 °C) is »525 DD from hatch to adult escape (434 DD was observed for D. virgifera virgifera). By adding data provided by other studies for the egg stage, it would take »865 DD for adult to emerge in the field. This number is approximately 150 DD shorter than what was found by other authors to obtain adult emergence in the field under fluctuating temperatures. The authors concluded that these data could serve as a basis for prediction models to be used for a better timing of chemical treatments against D. barberi.
Sources
Woodson, W.D.; Jackson, J.J. (1996) Development rate as a function of temperature in northern corn rootworm (Coleoptera: Chrysomelidae).
Annals of the Entomological Society of America, 89(2), 226-230.
Jackson, J.J.; Elliott, N.C. (1988) Temperature-dependent development of immature stages of the western corn rootworm, Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae).
Environmental Entomology, 17, 166-171.