June 14, 2013
A biopesticide developed from fungal spores is set to save cotton farmers millions of dollars by controlling heliothis pupae and significantly reducing the need to cultivate cotton soils. Department of Primary Industries (DPI) research at the Australian Cotton Research Institute in Narrabri has shown excellent preliminary results from the new strain of environmentally-friendly biopesticide developed by DPI Senior Principal Research scientist Dr Robert Mensah. “Trials this last season showed that about 80 per cent of Helicoverpa larvae treated with the biopesticide failed to develop into pupae,” said Dr Mensah. “The results when integrated with other pest control tools such as attract-and-kill larvae could eliminate the need for Helicoverpa pupae busting – a problem cotton producers still face which requires the cultivation of the soil to destroy overwintering pupae. “Pupae busting involves financial costs and restricts the uptake of minimum tillage farming which can help prevent erosion, conserve soil moisture and enhance soil carbon.” Dr Mensah said the fungal spores when applied to larvae germinate within 3 to 4 days and the roots penetrate and kill the larvae before they turn into pupae or kill the pupae before they emerge as moths. “The strain of fungus we have developed is capable of surviving longer in the low humidity of cotton growing areas – which makes it an efficient biopesticide for dryland farmers as well as irrigators. “It highlights the tremendous potential for biopesticides and also semiochemicals as safe biological alternative pest controls,” he said. “They can complement IPM and the transgenic cotton technology to further reduce synthetic insecticide use in the cotton industry.” Dr Mensah said transgenic cotton crops had resulted in less synthetic insecticide use against Helicoverpa. ”But sucking pests such as green mirids, cotton aphids, green vegetable bugs and silverleaf white flies have emerged as major pests. “In addition, the cotton industry still faces a lack of synthetic insecticides for seed treatment to manage soil inhabiting pests such as wireworms and cutworms, seedling pests such as thrips and aphids that can affect seed germination, plant stand and yield.” Dr Mensah said the development of new biopesticides and semiochemicals for pupae busting, seed treatment and sucking pest management is important for the cotton industry’s sustainability. “Results of a seed treatment trial conducted in wireworm infested fields showed that 100 per cent of the fungus and semiochemical-treated seeds germinated and effectively controlled seedling pests similar to synthetic insecticide treated seeds.” The Research to develop biopesticides and semiochemicals is funded by the Cotton Research and Development Corporation (CRDC). Dr Mensah has worked closely with the CRDC, growers and commercial partners such as Growth Agriculture and Becker Underwood Pty Ltd in developing these technologies, which may have applications in many industries, including organic agriculture.