Lacewings (Mallada basalis) and minute pirate bugs (Buchananiella whitei) as potential biocontrol agents of western flower thrips (Frankliniella occidentalis) in strawberries: predation on different thrips stages in no-choice and choice tests

The strawberry (Fragaria × ananassa) is a significant economic crop in New Zealand, but has recently suffered substantial damage from western flower thrips (Frankliniella occidentalis), resulting in significant financial losses. This study first assessed the predation ability of two commercially available predatory insects, the green lacewing, Mallada basalis (first-instar larvae) and Buchananiella whitei (adults), on western flower thrips nymphs and adults under no-choice conditions in a laboratory setting. Next, the preferences of the two predatory insects for different life stages of the thrips were tested in the same laboratory setting under choice conditions. In no-choice test, both predator species consumed the highest number of first instar thrips nymphs, second highest the second instar thrips nymphs, and the lowest the thrips adults. In choice test, both predator species ate significantly fewer thrips adults than immature life stages; further analysis of Manly index confirmed the lowest preference for thrips adults by both predator species. This study provides the first insight into the potential of these two predatory insect species for biocontrol against western flower thrips. The potential of these two predator species in controlling western flower thrips on strawberries should be further tested in greenhouses or field plots to better understand their roles in integrated pest control systems.