Spatial and temporal dynamics of Amblypelta lutescens lutescens Distant (Heteroptera: Coreidae) in avocado crops

The native banana-spotting bug, A. l. lutescens, is a major polyphagous insect pest of many tropical and sub-tropical horticultural crops in Australia, including high valued commodities such as avocados (Persea americana). The cryptic nature of A. l. lutescens makes it difficult to sample and much about its ecology and behaviour remains poorly understood. An attractant lure based on the main components of the semio-chemicals emitted by male A. l. lutescens has been developed and incorporated into a trap and this has created opportunities to investigate A. l. lutescensin the field.

An ongoing two year study is investigating spatial and temporal dynamics of the pest in avocado crops using a grid (36 metres x 36 metres) of traps across two 4-6 ha avocado blocks (cv. ‘Shepard’). Higher A. l. lutescens populations were observed from October through to June with peaks occurring in October, February and May. Spatial Analysis by Distance IndicEs (SADIE) indicated very low occurrences of aggregated adult (4-17%) and nymph populations (4-16%) based on weekly pheromone trap counts from both avocado blocks; in most weeks trap counts were randomly distributed. Year-end summary count data indicated significant adult and nymph spatial aggregations in both avocado blocks near other horticultural crops and native vegetation. Adult male and female count data from both avocado blocks indicated a biased sex ratio of 1.2:2.1. The implications of these results for pest management are discussed.