A Preliminary Study on Identifying the Predator Community of Invasive Bactericera cockerelli (Hemiptera: Triozidae) and Developing Molecular Identification Tools for Testing Field Predation

TL;DR

This study identifies natural predators of the invasive tomato potato psyllid in Western Australia and uses molecular tools to confirm their predation, supporting potential biological control strategies.

Contribution

The study is the first to confirm field predation on Bactericera cockerelli by native predators in Australia using molecular techniques.

Findings

Green lacewings and ladybirds were the most abundant predators of B. cockerelli in Solanaceous crop fields.

Molecular analysis showed 45% of tested predators consumed B. cockerelli, with Coleopteran predators having the highest positivity rate.

Predatory spiders were common but their populations varied between years.

Abstract

This study investigated generalist predators in Solanaceous crop fields across Western Australia to understand their role in controlling the invasive pest Bactericera cockerelli. A diverse range of predator species, including insects from Neuroptera, Coleoptera, Diptera and Hemiptera, as well as spiders, was identified. Laboratory feeding trials and molecular analysis confirmed that many of these predators consumed B. cockerelli in the field. Notably, green lacewings and ladybirds were the most abundant predators, with capsicum fields supporting the largest populations due to floral resources. Molecular techniques revealed that 45% of the tested predators consumed the pest, with Coleopteran predators showing the highest positivity rates, followed by Neuroptera and Hemiptera. Predatory spiders were also common, though their populations varied between years. This study emphasizes the utility of molecular tools for monitoring predation and suggests that these predators could play a key role in integrated pest management strategies for B. cockerelli in Australia.

The tomato potato psyllid Bactericera cockerelli (Hemiptera: Triozidae) is a significant insect pest of Solanaceae. In early 2017, it was first detected in Perth, Western Australia. The objective of this work was to identify predator species of B. cockerelli occurring in fields of Solanaceae in Western Australia. Predatory insects and arachnids were sampled using sweep netting in some of the major Solanaceae-growing regions in the south-west of Western Australia in 2021 and 2022. Several laboratory feeding trials were conducted to develop PCR primers that could detect the DNA of B. cockerelli in predators that had fed on B. cockerelli rather than on alternative diets. The primers were then used to screen predators collected from the field to identify those that had been feeding on B. cockerelli. In the two years of field sampling, the predators collected represented a broad taxonomic range. The most abundant predator was green lacewing followed by ladybirds. Further, we analysed predators belonging to seven insect taxa (one Neuroptera, two Hemiptera and four Coleoptera) for the presence of B. cockerelli DNA. We found that 45% of the individual insects from all taxa that we caught were positive for B. cockerelli DNA, and Coleopteran predators showed the highest rate of positive results. This is the first report confirming predation on invasive B. cockerelli by the resident predator community in the field in Australia.

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