Location: Fruit and Nut Research
Title: The potential for controlling Pangaeus bilineatus (Say) (Heteroptera: Cydnidae) using a combination of entomopathogens and an insecticide Authors
|Mbata, George -|
|Shapiro Ilan, David|
Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 27, 2013
Publication Date: N/A
Interpretive Summary: Burrower bugs such as the species, Pangaeus bilineatus, can be important pests of various crops in the southern United States. Current control methods for these pests, which are based on the use of chemical insecticides, have not been very successful. Also chemical pesticides can be harmful to the environment. Our objective was to determine if naturally-occurring, environmentally-friendly, nematodes or fungi applied alone or in combination with a standard chemical insecticide would provide superior levels of burrower bug mortality compared with the standard chemical (chlorpyrifos) applied alone. The beneficial nematodes and fungi that we used in this study are safe bio-pesticides that are applied commercially to control various economically important pest species; these nematodes and fungi do not harm plants, mammals or the environment. The nematode treatment and the fungus treatment when applied alone were not effective in killing the burrower bug. The combination of chemical insecticide plus fungus was not advantageous relative to using the chemical by itself. However, the chemical insecticide plus nematode treatment caused the highest level of mortality in the burrower bug. The interaction between the chemical and nematode was synergistic, meaning that the combined treatment caused a higher level of mortality than the sum of the two agents acting alone. Based on the observation of synergy, the combination of the nematode (called Heterorhabditis bacteriophora) and chlorpyrifos should be investigated further for potential adoption in the management of burrower bugs such as P. bilineatus or other insects such as pecan pests.
Technical Abstract: It is important to develop new environmentally friendly methods of insect pest suppression. One avenue to reduce chemical pesticide use is to combine the chemicals with biocontrol agents that produce synergistic levels of insect mortality. The aim of this study was to explore this approach of leveraging synergy for insect control. The model insect host was the peanut burrower bug, Pangaeus bilineatus, which is an important pest of peanut. Current control methods for this pest, which are based on the use of chemical insecticides, have not been very successful. Our objective was to determine if entomopathogens applied alone or in combination with a standard chemical insecticide would provide superior levels of P. bilineatus mortality compared with the standard chemical applied alone. Specifically, we investigated the efficacy of an entomopathogenic nematode, Heterorhabditis bacteriophora and a fungus, Beauveria bassiana, applied alone or in combination with and chlorpyrifos. When applied as single treatments, the two entomopathogens were not pathogenic. However, the combination of the H. bacteriophora and chlorpyrifos caused the highest mortality. The nature of the interaction between H. bacteriophora and chlorpyrifos was synergistic, which is of particular interest given that the nematode was not pathogenic when applied without the insecticide. This is the first time a synergy is being reported between a nematode that was not pathogenic when applied alone and a chemical insecticide. B. bassiana and its combination with the chlorpyrifos did not significantly increase insect mortality compared with chlorpyrifos alone or the control. Based on the observation of synergy, the combination of H. bacteriophora and chlorpyrifos should be investigated further for potential adoption in the management of P. bilineatus; and the combination should be explored in other systems such as pecan.