Early detection of squash silverleaf and chemical control of Bemisia tabaci using imidacloprid

Abstract

Squash silverleaf induced by the geographical variant Middle East-Asia Minor 1 (MEAM1) of Bemisia tabaci (Gennadius) is an economically important disease of Cucurbita pepo L. in tropical and warm temperate regions of the world. Therefore, both early detection of disease severity and judicious use of insecticides are important for minimizing economic losses. Therefore, the aims of this study were to use chlorophyll fluorescence to detect squash silverleaf early and determine the best protocol for imidacloprid application. The results showed that chlorophyll fluorescence was positively correlated with disease severity of whitefly-infested plants. Foliar spraying was suitable for application to control MEAM1 in the high risk region because it could be rapidly implemented against whitefly infestations and because it has a high knockdown rate. Soil application was slow-acting but had a long-lasting effect and was suitable for implementation during the initial stage of a whitefly outbreak. Considering the overall insect control potential and the risks to the environmental contamination and human health, 0.3 g L⁻¹ imidacloprid is the recommended concentration using the two application methods.

Keywords:

• Bemisia tabaci
• chlorophyll fluorescence
• Cucurbita pepo
• imidacloprid
• squash silverleaf

Acknowledgements

This study was supported by the Key Program for Science and Technology of the Chinese Ministry of Education (project 206061) and the Jinhua Science Technology Foundation of China (project 2005-1-233). Thanks are also extended to Wenlong Zhou and Huihui Ying (College of Chemistry and Life Science, Zhejiang Normal University) for their assistance in cultivation of Cucurbita pepo.

Additional information

Notes on contributors

Hongfei Lu

The first three authors contributed equally to the work