Repellency of Five Mineral Oils AgainstDiaphorina citri(Hemiptera: Liviidae)

Abstract

The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), is the vector of huanglongbing, a destructive citrus disease worldwide. Horticultural mineral oils (HMOs) are commonly used for management of D. citri. In the past, repellency of HMOs against D. citri was reported. The primary objective of this study was to determine the repellency characteristics of 5 HMOs against D. citri. The settling and oviposition responses of D. citri to aqueous emulsions of the HMOs were assessed by bioassay. The relationships between repellency and carbon number distribution, as well as the emulsifying efficiency of each HMO were analyzed. The results showed that the various HMOs had significantly different behavioral repellent effects against D. citri. Correlation analysis using Pearson's correlation coefficient indicated that the repellent effects of the HMOs against D. citri were significantly correlated with the mass percentages of C22, C23 and C24, but not with their emulsifying efficiencies. These results can help to select and develop HMOs with high repellencies for D. citri control. The mechanism of HMO repellency against D. citri is unclear and needs to be investigated.