Recent research on pesticides to manage the chive maggot, Bradysia odoriphaga Yang et Zhang (Diptera: Sciaridae) in China.

The chive maggot, Bradysia odoriphaga Yang et Zhang (Diptera: Sciaridae), is a devastating pest for Chinese chive and other vegetables in China Most farmers take pesticides as their first tool to control this pest. Phoxim, imidacloprid, thiamethoxam, clothianidin and cypermethrin are the common used pesticides but the development of the resistance against these compounds is the main concern, especially phoxim. Insect resistance to thiamethoxam and clothianidin is much lower than that to phoxim although it varies among different area. This issue can be greatly alleviated by rotating the use of the pesticides with different mode of action. Moreover, proper application method can substantially improve control effect. Pesticides with new mode of actions are under intensive investigations and chlorfenapyr has been shown to be a potent alternative pesticide for the control of the chive maggot. The pest shows low resistance to this chemical. Furthermore, many promising pesticides derived from biological products such as plant allelochemicals and microbial metabolites have been discovered and tested for their controlling efficacy. These pesticides are generally environmental-friendly and strongly encouraged in China now. They usually have relatively lower control effect in contrast to the traditional pesticides so they are suggested be used along with the rapid knock-down pesticides. Except for these pesticides, non-chemical methods are also vigorously developed to control B. odoriphaga, among which increasing soil temperature by covering the crop with plastic mulch film in hot days is very effective. This method developed by Youjun Zhang and his colleague has great potential to substantially decrease the usage of pesticides against the chive maggot. Overall, the multiple choices in the toolbox can help suppress the pest population under the economic threshold and greatly reduce the resistance of this pest to pesticides.