Control of HLB-spreading Asian citrus psyllids (ACP) can be improved with dormant winter sprays and targeted perimeter applications, according to Citrus & Specialty Crop Expo presenter Jawwad Qureshi, associate professor of entomology at the University of Florida Institute of Food and Agricultural Sciences Southwest Florida Research and Education Center.
Dormant sprays
Qureshi explained that ACP adults overwinter, and most young shoots emerge in spring. He said dormant winter sprays significantly reduce psyllid populations, but added that further sprays are required during the growing season to maintain control.
Grove perimeters
Qureshi also presented research on ACP spatial distribution in Texas citrus groves. Data showed that psyllid infestations were higher in grove perimeters, with border trees typically infested first. In many cases, one generation was completed on border trees before inner trees were affected. ACP densities decreased with distance from the grove edge.
Perimeter sprays were reported to kill psyllids while leaving interior trees untreated, providing refuge for natural ACP enemies. Qureshi stated that focusing on perimeter treatments can support integrated pest management and reduce costs.
He also noted that ACP showed a clear preference for perimeter trees, while predators and parasitoids were found both in perimeter and interior areas. Psyllids experienced similar levels of natural suppression in both zones. According to Qureshi, the higher ACP concentrations in perimeter areas, combined with natural biological control throughout the grove, suggest that perimeter spraying is a useful tactic for reducing psyllid populations while allowing beneficial organisms to remain active in untreated areas.
Source: Citrus Industry
