Pigeon Pea: Living upto Expectations as a Refuge with Bollgard II® Cotton in Australia?
Abstract:Australian cotton growers plant refuge crops to generate Bt susceptible Helicoverpa spp. moths. These susceptible Helicoverpa help to reduce the likelihood that these key pests will develop Bt resistance. In the 1990s, unsprayed pigeon pea was identified as the most Helicoverpa productive and it is now the most popular refuge crop grown in association with Bt cotton in Australia. But Australian cotton production systems have changed since the 1990s. One dramatic change has been the reduction in pesticide use in cotton crops since the introduction of Bt cottons. A reduction in pesticide use in such crops probably means an increase in invertebrates, including beneficials, more broadly in the landscape. Refuges can, themselves, be favourable habitats for predators and parasitoids. It is, therefore, possible that any increase in natural enemies of Helicoverpa could have reduced the ability of refuge crops such as pigeon pea to produce susceptible moths. Indeed, there have been suggestions in the cotton industry that this has happened in recent years. Surveys of live Helicoverpa spp. pupae have been conducted in pigeon pea crops over the last 20 years to see if the performance of refuges has declined. Researchers also looked for any increase in pupal parasitoids of Helicoverpa as parasitism is likely to be an important constraint on moth production. The results so far have shown there is no convincing evidence of any such changes.
Keywords: BENEFICIALS; BOLLGARD II; BT; BT RESISTANCE; BT SUSCEPTIBLE; CONVENTIONAL COTTON; COTTON; HELICOVERPA; INVERTEBRATES; PARASITES; PESTICIDE; PIGEON PEA; PREDATORS; REFUGE; REFUGE CROP; RESISTANCE; UNSPRAYED COTTON
Document Type: Research Article
Publication date: 2011-02-01