Effects of invertebrate pests on white and annual clovers in dryland soil

摘要

Two experiments were carried out at Ruakura in soil taken from Whatawhata hill country pasture. The relative susceptibility of several annual clovers {Trifolium spp.) and perennial white clover (T. repens) to slugs (Deroceras reticulatum), clover rootweevil (Sitona lepidus) adults, native crickets {Nemobius sp.) or wheat bugs (Nysius huttoni) was tested by sowing seed of the clovers into separate rows in turf. Susceptibility of clovers to clover cyst nematode (Heterodera trifolii) was tested by sowing each clover variety into Whatawhata soil inoculated with the nematode. Plant growth was assessed in both experiments 4 weeks after sowing. White clover was more susceptible to pests than the annual clovers, with slugs and clover root weevil significantly reducing seedling survival, and clover cyst nematode significantly reducing plant growth. Subterranean clover (T. subterraneum) cv. Denmark was the least affected by pests, showing no significant reduction in survival in the presence of slugs, the most damaging pest, and no significant decrease in plant root and shoot dry weight when exposed to nematodes.