A new method of gall mite management: application of artificial defoliation to control Aceria pallida

Artificial defoliant is widely applied to cotton to facilitate mechanical harvesting and successfully controls leaf diseases by blocking pathogen epidemical cycles; however, this technique is rarely used to control herbivores. Because many eriophyoid mites live and reproduce in galls, the control of these mites by pesticides is usually limited. However, the abscission of galled foliage is lethal to tiny mites with low mobility. Therefore, artificial defoliation should be effective in controlling gall mites. Here, the effects of defoliant on the control of the goji berry Lycium barbarum L. gall mite Aceria pallida Keifer were compared with those of pesticides under field conditions over 3 years. Our results showed that artificial defoliation enabled almost complete defoliation and timely refoliation. A. pallida galls fell off with the defoliation, and then regenerated foliage escaped from mite attack. After defoliant application, the densities of mite galls decreased by 84.1%, 80.3% and 80.3% compared with those found in the pesticide (undefoliated) treatment in 2012, 2013 and 2014, respectively. Artificial defoliation achieved much better control of gall mites than pesticides.