Location: Insect Behavior and Biocontrol ResearchTitle: Survival and behavior of the insecticide-exposed predators Podisus nigrispinus and Supputius cincticeps (Heteroptera: Pentatomidae) Author
|De Castro, Ancideriton|
|Legaspi, Jesusa - Susie|
Submitted to: Chemosphere
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/29/2013
Publication Date: 7/20/2013
Citation: De Castro, A.A., Correa, A.S., Legaspi, J.C., Guedes, R.N., Serrao, J.E., Zanuncio, J.C. 2013. Survival and behavior of the insecticide-exposed predators Podisus nigrispinus and Supputius cincticeps (Heteroptera: Pentatomidae). Chemosphere. http://dx.doi.org/10.1016/j.chemosphere.2013.05.075. Interpretive Summary: The velvetbean caterpillar is an important pest of soybean. Pest management of the caterpillar can include a combination of controls, such as insecticides and its natural enemies, predatory stinkbugs. To be effective, the controls must be compatible. Therefore, Scientists at the USDA-Agriculture Research Service, Center for Medical, Veterinary and Agricultural Entomology, Gainesville, Florida, studied the effectivenesss of several types of insecticides against the caterpillar, as well as their effects on two species of predatory stinkbugs. We tested several types of insecticides: deltamethrin (plant-based), methamidophos (conventional), spinosad (microbial) and chlorantraniliprole (novel “reduced risk”). Spinosad was most toxic to the pest, followed by chlorantraniliprole, methamidophos and deltamethrin. Against the predators, chlorantraniliprole demonstrated low toxicity. In comparison, methamidophos, spinosad and deltamethrin led to 100% mortality of both predators. In summary, this study shows that for management of the velvetbean caterpillar, chlorantraniliprole is most compatible with the use of predatory stinkbugs and therefore most likely to result in successful control.
Technical Abstract: Pentatomid stinkbugs are important predators of defoliating caterpillars in agricultural and forestry systems, and knowledge of the impact of insecticides on natural enemies is important information for IPM programs. Thus, we assessed the toxicity and behavioral sublethal response of the predators Podisus nigrispinus and Supputius cincticeps exposed to deltamethrin, methamidophos, spinosad and chlorantraniliprole, insecticides commonly used to control the velvetbean caterpillar, Anticarsia gemmatalis. With the exception of deltamethrin for S. cincticeps, all insecticides were more toxic to the prey than to these natural enemies. The recommended field concentration of deltamethrin, methamidophos and spinosad for controlling A. gemmatalis caused 100% mortality of P. nigrispinus and S. cincticeps nymphs. Chlorantraniliprole was less toxic to these predators resulting in mortality of less than 10% when exposed to 10 times the recommended field concentration for a period of 72 hours. All insecticides were effective in controlling A. gemmatalis. Chlorantraniliprole proved to be most selective with low toxicity to P. nigrispinus and S. cincticeps nymphs. Behavioral pattern changes in predators were found for all insecticides, especially methamidophos and spinosad resulting in insecticide irritability (i.e., avoidance after contact) in both predator species. However, insecticide repellence (i.e., avoidance without contact) was not observed in any of the insects tested. To know the lethal and sublethal effects of pesticides on natural enemies is of great importance for IPM, and our results indicate that substitution of pyrethroid insecticides and organophosphate insecticides by chlorantraniliprole can be a key factor for the success of IPM programs of A. gemmatalis in soybeans.