Effect of temperature on efficacy of three natural substances to Colorado potato beetle, Leptinotarsa decemlineata (Coleoptera: Chrysomelidae)

Abstract

Azadirachtin, refined rape oil and slaked lime Á three natural substances with insecticidal potential Á were tested under laboratory conditions for their efficacy against larvae and adults of Colorado potato beetle, Leptinotarsa decemlineata, at 158C, 208C, and 258C. General statistical analysis (all developmental stages and all insecticidal substances taken into account) was performed on the results of the mortality rates of the individuals and no statistically significant differences between the temperatures were observed on the fifth day after application. At all temperatures, the influence of insecticidal substances in question as well as the interaction between the insecticidal substance and the developmental stage of the pest on mortality rates were significant. The individual statistical analysis (a specified developmental stage of the pest at a specified temperature) revealed the maximum efficacy of the refined rape oil at 158C and 208C, the adults being the most sensitive developmental stage (mortality rate about 90%). Other substances tested were less effective, and in general the mortality rate of either larvae or adults did not exceed 50%. In the case that the efficacy of the refined rape oil in controlling the population of the adults of the Colorado potato beetle is confirmed also in field trials, this could be the basis for a better strategy in controlling the overwintered Colorado potato beetles on potato.

Field Testing of Efficacy of Three Environmentally Friendly Insecticides Against Colorado Potato Beetle (Leptinotarsa Decemlineata [Say], Coleoptera, Chrysomelidae) on Potato-Evaluation of the Effect on Yield

“…Foliar application of environmentally safe insecticides studied in our research did not show satisfying efficacy of controling CPB and their influence on potato yield although the results from a laboratory test (Trdan et al, 2007) were promissing. The low efficacy of tested insecticides could be explained with the rapid degradation under high temperature and UV light (Johnson et al, 2003;Barrek et al, 2004).…”

“…Although reports of earlier studies indicate that several environmentally friendly insecticides could offer an alterantive to chemical control of CPB (Trdan et al, 2007;Hiiesaar et al, 2009;Amiri-Besheli, 2010) our current research confirm such results only partly. Namely in 2008, the potato sprayed twice with azadirachtin, gave the highest yield.…”

“…Trdan et al (2007) confirmed in a preliminary laboratory investigation a high susceptibility of CPB adults and larvae to refined rape oil (high mortality rate of adults five days after treatment), while azadirachtin was less effective in their research.…”

“…In addition, to contact toxicity, systemic activity has been documented (Gill & Lewis, 1971;Osman & Port, 1990). The efficacy of azadirachtin to CPB has been demonstrated under laboratory conditions by Trdan et al (2007). Several neem extracts have been commercialized in the United States and Europe (Immaraju, 1998).…”

Effects of organic products with insecticidal action on key insect pests in alfalfa seed production

“…These plants are also used for many uses and represent one of the economically most important classes of compounds with broad usage in integrated pest management and organic agriculture (Isman, 2006;Trdan et al, 2007). In addition, pyrethrum and neem products are environmentally friendly and safe to non-target organisms (Kraiss, Cullen, 2008a, b).…”