Agrichemical use on wheat and barley crops in New Zealand in 2008-09

Agrichemical usage on cereal crops grown in New Zealand was assessed from spray diaries for 45 barley fields and 81 wheat fields. From the 2008-09 growing season, 2.13 kg ai/ha (0.35 kg ai/t grain) and 2.93 kg ai/ha (0.31 kg ai/t grain) of agrichemicals of low-moderate human toxicity were applied to barley and wheat fields, respectively. For each crop, 0.31 and 0.33 kg ai/ha of fungicides, 0.14 and 0.28 kg ai/ha of insecticides, 1.46 and 1.47 kg ai/ha of herbicides and 0.22 and 0.85 kg ai/ha of plant growth regulators were applied. The data were reviewed with respect to pesticide resistance management guidelines. Although more than half of the agrichemical active ingredients (ai) applied, mostly herbicides, were classified by the Hazardous Substances and New Organisms (HSNO) Act 1996 as having high water or soil eco-toxicity, the amounts applied to the cereals on a per hectare basis were small (1.14 and 0.84 kg ai/ha, respectively) compared with that applied to comparable horticultural crops. Agrichemical use in cereal crops in New Zealand has remained generally static since 1998 despite incremental increases in yield, reflecting the arable sector's focus on protecting and building farm biodiversity, integrated pest management and agrichemical management.