Effects of Dimpropyridaz on Feeding Behavior, Locomotivity and Biological Parameters of Aphis Gossypii

Abstract

Aphis gossypii is a worldwide agricultural pest insect that has developed resistance to multiple pesticides. Dimpropyridaz is a new chordotonal organs regulator and has been registered for control of sap-sucking insects including A. gossypii. For the aim to effectively apply dimpropyridaz for cotton aphid control, it is necessary to clarify the toxic effects of dimpropyridaz on cotton aphids. In present work, the effects of dimpropyridaz on feeding behavior, locomotivity and biological parameters of A. gossypii were investigated. The bioassay results showed that dimpropyridaz had good insecticidal activity against A. gossypii, with a LC50 of 1.914 mg/L at 72 h after treatment. Moreover, the dimpropyridaz treated A. gossypii showed obvious poisoning symptoms of dehydration and shrivel. Through the gentle-touch experiment and feeding experiment, it was found that dimpropyridaz treatment had significant adverse impacts on the locomotivity and feeding behavior of A. gossypii. Compared with the control group, the coordinated movement ability of the treated A. gossypii attenuated. In addition, dimpropyridaz treatment inhibited feeding behavior of A. gossypii, with the feeding rate decreased by 62.00%, 64.00% and 71.67% after treatment with 50 mg/L dimpropyridaz for 24 h, 48 h and 72 h, respectively. Furthermore, the treatments with LC10 and LC30 of dimpropyridaz significantly reduced the longevity and fecundity of F0, and led to a decrease of the relative fitness of F0 to 0.48 and 0.32, respectively. The net reproductive rate (R0) and mean generation time (T) of F1 generation also significantly decreased, moreover the oviposition days was significantly shortened. In addition, after 72 h treatment with LC30 dimpropyridaz, the gene expression levels of JHEH and USP of cotton aphids significantly increased, while the expression of EcR and INRS decreased. The expression level of FOXO and INR was also significantly downregulated in cotton aphids treated with dimpropyridaz at LC10 and LC30 for 72 h. These results provide basis for clarifying the toxicology of dimprppyridaz to cotton aphids, and also are beneficial to scientific control of cotton aphid using dimpropyridaz.

Keywords: dimpropyridaz, Aphis gossypii, feeding behavior, locomotivity, biological parameters