Recruiting lady beetles using olfactory and visual cues for the biocontrol of Acanthococcus lagerstroemiae (Hemiptera: Eriococcidae)

Abstract

Acanthacoccus lagerstroemiae (crapemyrtle bark scale, CMBS) is an exotic scale insect that feeds on the sap of crapemyrtle trees as its primary host. Heavy Infestations of CMBS leads to reduced flowering and sooty mold growth on the leaves and branches. This reduces the aesthetic value of crapemyrtle trees in urban landscapes. Lady beetles (Coleoptera: Coccinellidae) are generalist predators and they have been observed feeding on CMBS. Several laboratory and field studies have demonstrated the attraction of lady beetles to olfactory and visual cues. In order to achieve biocontrol of CMBS and reduce dependence on chemical control methods, we evaluated responses of lady beetles to olfactory lures and yellow visual attractants on infested landscape trees. Significantly more lady beetles were recruited to unbaited (Control) infested trees and infested trees baited with a combination of Predalure and Limonene compared to trees baited with limonene alone. Similarly, yellow rectangular panels placed 1m above the base of an infested tree also recruited up to twofold more lady beetles than control trees. Significant reduction in CMBS was observed on infested trees with yellow rectangular panels in tree’s canopy. Yellow rectangular panels are more likely to recruit lady beetles in an urban landscape than olfactory lures. Management of CMBS is currently achieved using systemic insecticides. This study provides a new tactic to recruit lady beetles for biological control of CMBS, an advancement toward integrated management of this exotic pest.