What was it all about?

From 2017 to 2020, this project identified and assessed the impact of integrated pest management (IPM) strategies on the sustainable control of redberry mite in commercial blackberry production systems in Australia. Monitoring protocols were also developed to enable a more predictive approach to managing redberry mite.

Australia’s commercial blackberry industry is expanding rapidly but relies on the consistent production of high-quality fruit. Redberry mites are a minute plant-feeding mite in the superfamily Eriophyoidea that infests blackberries in many growing regions. Redberry mite feeding results in the incomplete and/or uneven ripening of blackberry fruit. The damaged fruit is unmarketable resulting in significant crop losses.

The project team interviewed growers to examine on-farm management systems, conducted a national fruit survey to assess redberry mite distribution and prevalence, and implemented IPM field trials at commercial production sites in Victoria’s Yarra Valley and in Tasmania. The trials consisted of both predatory mite releases and a spray reduction trial, with redberry mite and predatory mite populations monitored on both blackberry fruit and within winter buds.

The results indicated that crop losses are more common in later season cultivars. Cultural control strategies including wild blackberry removal, cultivar selection and crop hygiene were highlighted as IPM strategies to limit redberry mite populations.

Several predatory mite species were also assessed in field trials. The results confirmed that Typhlodromalus lailae and Typhlodromus occidentalis are not effective for controlling redberry mite. However, Typhlodromus doreenae was isolated on both ripe fruit and within winter buds indicating they do persist in the crop and may impact redberry mite. Typhlodromus dossei was also commonly observed in fruit sourced from Victoria. Little is currently known about T. dossei except that its presence is commonly associated with high numbers of Eriophyid mites.

The spray reduction trial confirmed that the spray program currently used by many Australian producers successfully reduces redberry mite populations but also has severe impacts on predatory mite populations. It was found that the adoption of a ‘softer’ chemical management program reduces redberry mite populations without impacting on predator populations or fruit quality.

These outcomes were extended to industry using online resources, workshops and articles in industry magazines and newspapers.

ACT NOW

The redberry mite page within the Berries Australia website holds many of the extension and information materials developed by the project team.

Read these articles about the project, published in the Australian Berry Journal:

• Redberry mite unpacked, Summer 2020 edition, pp99-102
• ‘Doreen’ to lend a helping hand in blackberry crops, Summer 2019 edition, pp76-77
• The secret life of redberry mite in blackberries, Spring 2018 edition, pp35-36

Along with these stories featuring the team’s research appeared in several Tasmanian newspapers:

• Tasmanian research project benefits national berry growers, Launceston Examiner, 21 February 2018
• TIA project studies blackberry colour, Burnie Advocate and Launceston Examiner, 7 December 2017
• More Mites might be the key to help berries, Launceston Examiner, 28 February 2019

Watch this mite extraction demonstration video prepared by the project team.