Thresholds for Plague Thrips in the Victorian strawberry industry

Client: Horticulture Australia Limited

Project code: BS12003

Project completed: 2014

The aim of this two-year research project was to determine whether or not large numbers of plague thrips (Thrips imaginis) cause damage to strawberry flowers and berries. Trials were conducted over two consecutive growing seasons and the conclusion from the first season was that up to 50 plague thrips in a flower caused no damage to the subsequent berry. The results of the second season suggest that even more than 100 thrips per flower caused no damage to subsequent fruit.

The impact of different numbers of thrips on strawberry formation was assessed in two ways.  The first involved using the naturally occurring levels of plague thrips (as measured by the average number of thrips per flower) and the second method involved caging flowers with known numbers of thrips.