New environmentally-friendly solution to major cotton pests

NSW DPI research scientist Dr Robert Mensah
NSW DPI research scientist Dr Robert Mensah inspects a cotton crop at the Australian Cotton Research Institute near Narrabri where he has been working to develop an environmentally-safe fungus to manage cotton pests.

Those little suckers who feed on cotton plants and cause economic damage to crops could soon be managed with a new environmentally-friendly pest control.

NSW Department of Primary Industries researcher and director of the Australian Cotton Research Institute (ACRI), Robert Mensah, said sucking pests, which have recently emerged as a major pest of cotton, could be managed with a natural fungus.

"We have discovered a native Australian fungus which kills soft-bodied sucking pests including green mirids, aphids, mites and early-stage heliothis larvae," Dr Mensah said.

Dr Mensah has been working with the Cotton Research and Development Corporation and commercial partners, Becker Underwood Pty Ltd, to develop a formulation of the fungus which can be applied to crops with standard ground rigs.

"While the fungus occurs naturally in the field it’s taken many years of intensive research to develop a stable biological spray which effectively controls pests," he said.

"Specially reared fungus spores are mixed in oil and then added to a water solution which is sprayed on crops in the same way as a synthetic chemical treatment."

This year in a trial at the ACRI near Narrabri, the cotton crop treated with the fungus yielded more than five bales per acre (12.5 bales per hectare), which is as good as or better than results which could be expected using harsher chemical sprays.

According to Dr Mensah a biological control produced from the fungus promises to contribute to a sustainable local cotton industry.

"The fungus attacks only soft-bodied sucking pests and hard-bodied beneficial insects, including ladybirds, red and blue beetles, shield bugs and lacewings which help manage cotton pests, will not be harmed.

"When the sucking pests come in contact with the fungus, it germinates and invades the insect’s body tissue and the pest dies in three to seven days."

Next season large-scale trials will be run on cotton farms prior to submitting an application for the commercial registration of the bio-control fungus with the Australian Pesticides and Veterinary Medicines Authority.