Avocado lace bug (ALB), Pseudacysta perseae, is a sap-feeding insect pest of avocado trees that feeds on the underside of avocado leaves. Feeding damage from ALB is indicated by medial areas of necrotic leaf tissue with these areas becoming larger as new generations eclose and feed on the same leaves. Eventually, areas of necrosis on leaves become sufficiently large that the leaves are prematurely dropped from the tree. Severe ALB infestations can lead to a large proportion of leaves dropping resulting in underdeveloped fruit. Since its first observed population on Oah’u in 2019, ALB has become established on most of the remaining Hawaiian islands causing economic loss due to leaf drop and resulting decrease in avocado fruit size. Due to the challenging topography of Hawai’i and nature of ALB feeding, routine foliar sprays of pesticide typically are not economically sustainable or effective at controlling infestations, particularly for organic avocado orchards. However, soil drenches of imidacloprid have been shown to be highly effective in controlling ALB populations throughout a fruiting season due to its systemic properties in avocado trees, though no organic soil drench alternative is currently available. Emerging research has shown one active component of neem oil, azadirachtin, to have potential systemic properties in various species of plants. This study investigated how soil drenches of varying concentrations of azadirachtin in avocado tree seedlings affected ALB first instar survivorship and development over time. Results from this study will aid in developing an organic systemic management program for ALB infestations in Hawai’i.
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