Use of predatory mites for long-term prevention of rust mite, bud mite and other pest mite outbreaks in Australian vineyards

Abstract

This project aims to answer relevant research questions needed to ensure active role of predatory mites in Australian vineyards in controlling mite pests such as grape rust mite and bud mite. Natural predatory mite fauna is studied in cool climate vineyards, and predatory mite releases evaluated.

Summary

Designating pesticides ‘safe’ to predatory mites – Laboratory tests on detached soybean leaves embedded in cotton wool were used to test effects of wettable sulphur on Euseius victoriensis. Tests on detached French beans were used to test effects on Galendromus occidentalis. Tests were standardised across these two substrates as per (Bernard et al 2004) to provide direct comparison of results across test species. Tests were performed under “worst-case scenario” conditions. Worst-case pesticide exposure is exposure: (i) at highest registered field rate; (ii) to direct pesticide overspray/not just dry residue; (iii) of the youngest most susceptible life stage (freshly hatched 0-48 hours-old predatory mite juveniles); (iv) that mimics real conditions, spraying the initial food and water supply together with mites. (v) The length of the test is also important; 7-day mortality (not just 48-hour tests), and study of effects on female egg lay are essential for predatory mite testing by internationally established protocols for rigorous pesticide testing. This level of rigour is required to designate pesticides ‘safe’ to predatory mites. This project delivered such a high standard of testing, and could thus confidently assess wettable sulphur safety.