Phenology of greenhouse thrips (Heliothrips haemorrhoidalis) on kiwifruit vines, shelter trees and alternative host plants

The greenhouse thrips, Heliothrips haemorrhoidalis is a quarantine pest of kiwifruit. There is a need for reliable information on its phenology in kiwifruit orchards to inform the development of new management options. Numbers of larval, pupal and adult greenhouse thrips were counted on leaves of the two main kiwifruit cultivars Actinidia chinensis var. deliciosa (‘Hayward’) at two sites at different times and A. chinensis var. chinensis ‘Zesy002’ at one site. Greenhouse thrips were also counted on leaves of shelter tree species Cryptomeria japonica, and other plants present on kiwifruit orchards, blackberry (Rubus fruticosus s.l.), barberry (Berberis glaucocarpa), and wineberry (Aristotelia serrata) across a number of sites at different times. There was a strong seasonal pattern to the phenology of greenhouse thrips and it was relatively synchronous for all the host plants surveyed. In general, number of greenhouse thrips on foliage increased from January to peak in April or May before declining in late autumn or winter and remaining low until the following January or February. The phenology of greenhouse thrips followed the same seasonal pattern for a variety of host plants found on kiwifruit orchards at sites in the Bay of Plenty across two two-year time periods. Therefore, host species does not appear to be a factor affecting the phenology of thrips. Other, non-host factors such as microclimate may be important drivers of phenology but they require further study. The consistency of the seasonal pattern of relative abundance means that there is a well-defined window to target for thrips management.