Nationwide survey of pests and diseases of cereal and grass seed crops in New Zealand. 1. Arthropods and molluscs.
A national survey of four cereal and two grass seed crops was conducted by the New Zealand Plant Protection Centre from October 1995 to February 1996. Approximately 85 000 plants were inspected at 332 sites in the main cereal growing areas of New Zealand. In addition to the previously known invertebrate species associated with cereal and grass seed crops, 93 new organism-host associations were recorded for wheat (21 primary pests), 85 new associations for barley (22 primary pests), 40 new associations for oats (8 primary pests), 25 new associations for ryecorn (3 primary pests), 57 new associations for ryegrass (15 primary pests) and 29 new associations for brome grass (5 primary pests). Cereal thrips (Limothrips cerealium), wheat sheath miner (Cerodontha australis) and Argentine stem weevil (Listronotus bonariensis) were the most common pests found in this survey. Chamaemyia polystigma, a predatory fly new to New Zealand, was recorded on barley, brome grass and ryegrass. One undescribed species of Thysanoptera was found on wheat from Mid Canterbury.