Temperature-Dependent Development and Cold Tolerance of Microtheca ochroloma (Coleoptera: Chrysomelidae), a Pest of Cruciferous Crops in the Southeastern United States

Abstract

The yellowmargined leaf beetle, Microthecaochroloma (Stål) (Coleoptera: Chrysomelidae ), is an adventive pest of cruciferous crops in the southeastern United States. Despite its pest status, there is limited information about the infiuence of temperature on development and survival of M. ochroloma. The objectives of this study were to assess the effect of temperature on the development and survival of immature stages, and determine the cold tolerance of immature and adult stages. Development was evaluated at 15,20, 25, and 30°C, and cold tolerance was measured at 5,0, and -5°C inside environmentally controlled chambers. Survival of M. ochroloma from egg to adult was ≈80% at 15,20, and 25°C, but only 24% at 30°C. Mean developmental time was longest at 15°C (57 d) and shortest at 30°C (17 d). Leaf area consumed by the fourth instar was 7.4-fold lower at 30°C compared with consumption at 15, 20, or 25°C. The lower developmental threshold varied from 7.3 to 9.8°C and the total degree-days required to complete development from egg to adult was 333. At 5,0, and -5°C, the LT90 values for the first instar were shorter compared with all other stadia, suggesting that the first instar is the most susceptible to cold temperatures. Eggs were most cold tolerant, followed by pupae and adults. Based on the LT50 (13d) andLT90 (38d) of eggs at 0°C, the predicted northern distribution of M. ochroloma extends to Kansas, Illinois, Kentucky, and Virginia.

Crapemyrtle Bark Scale: A New Threat for Crapemyrtles, a Popular Landscape Plant in the U.S.

“…Mortality caused by cold and heat helps determine habitat suitability by a better understanding of the overwintering ability and heat-tolerance of exotic pests. For example, effects of cold temperatures to Microtheca ochroloma Stål (Coleoptera: Chrysomelidae) were studied by exposing different life stages of this chrysomelid to low temperatures for various time periods [60]. Upon the arrival of an exotic pest, thermal tolerance parameters can be useful for regulatory purposes to predict the potential distribution of the new pest in the adventive range.…”

Survival of cabbage stem flea beetle larvae, Psylliodes chrysocephala, exposed to low temperatures

“…Dependent on what triggers the onset and ending of an acclimated state and the speed of the process, insects can exhibit different degrees of survival during winter (Hiiesaar et al, 2009(Hiiesaar et al, , 2011(Hiiesaar et al, , 2012Khani & Moharramipour, 2010). Furthermore, insects can exhibit different stage-and even gender-specific mortality in response to low temperature (Addo-Bediako et al, 2000;Koch et al, 2004;Carrillo et al, 2005;Jensen et al, 2007;Buergi & Mills, 2010;Hiiesaar et al, 2011;Manrique et al, 2012).…”

Occurrence of arthropod pests associated with Brassica carinata and impact of defoliation on yield

“…The population density of each species was variable, but these findings indicate that there are several insect species that utilize B. carinata as a host in the southeast U.S. Several pests have been associated with species of Brassica spp. in the southeast U.S. (Loon et al, 2002;Manrique et al, 2012;Ramachandran et al, 2000;Reddy, 2017); however, this is the first report of pests associated with B. carinata. Plutella xylostella is a pest associated with brassica causing annual yield losses and management costs estimated at $2.3 billion (Zalucki et al, 2012).…”