Comparison of New Zealand perennial clovers for resilience against common pasture pests

Abstract

Clovers (Trifolium spp.) are vulnerable to a large number of invertebrate pests so pest resilience amongst 19 leading commercial or near release New Zealand-bred clover cultivars was compared. Laboratory feeding choice tests comparing foliage from the test clovers against Grasslands Kopu II as the standard confirmed that red clovers (T. pratense) were less preferred than white clovers (T. repens) by adult clover root weevil and clover flea. Grey field slug showed no preference between red and white clovers, with the white clover Grassland Prestige performing the best. Porina larvae had lowest weight gains on strawberry clover (T. fragiferum). Subsequent tests using neonate greenheaded leafroller larvae and an artificial diet made with freeze-dried foliage from cultivars in the most and least preferred subgroups indicated antifeedant compounds, rather than leaf morphology, are likely responsible for differences in feeding preferences between red and white clovers.