Fight the mites

Grain growers have access to an additional tool for control of redlegged earth mite, RLEM, in canola crops.

A Pegasus miticide-insecticide label has varied to include control of a potentially destructive mite, Halotydeus destructor, in canola.

Research by sustainable-agriculture research organisation Ceser through Grains Research and Development Corporation investment supported the registration.

Pegasus, a Group 12A insecticide, is a Syngenta product with the active ingredient of diafenthiuron.

GRDC pests manager Dr Leigh Nelson said the label variation was welcome news for the nation’s canola growers.

“RLEM is a major threat to a variety of Australian crops and pastures, and canola seedlings are among the most susceptible to attack,” she said.

“Feeding on canola seedlings by mites can cause distortion and shrivelling of leaves, and when infestation is at a significant level, affected seedlings might die.”

Dr Nelson said increasing RLEM resistance to commonly used chemistries was of concern to the grains industry, so the registration of another insecticide option helped in extending the longevity of available chemical controls.

“It’s another tool in the toolbox for our growers,” she said.

“But as is the case with the use of any available chemistries, for best results Pegasus should be used as part of an integrated pest management program that includes cultural practices, seed

treatments and rotation of insecticides with different modes of action.”

Based on the product label, farmers can apply Pegasus to canola from a cotyledon stage when action thresholds are reached.

Growers are advised thorough coverage is essential and they should not apply more than two applications in any one crop.

Four other chemical groups are registered to control RLEM in grain crops.

These are: organophosphates – Group 1B; synthetic pyrethroids – Group 3A; phenylpyrazoles – Group 2B; and neonicotinoids – Group 4A. The latter two are registered only for use as seed treatments.

Ceser director Dr Paul Umina said resistance to pyrethroids and organophosphates in RLEM was widespread in Western Australia.

“These resistances have also been detected in some South Australian mite populations and are expected to be confirmed in other regions in the future,” he said.

“Having more chemical options for management is crucial to the longevity of chemical options for RLEM.”

Syngenta’s Head of Portfolio ANZ, Peter Holmes, said working with the GRDC and Ceser to extend the label for Pegasus was part of Syngenta’s innovation model to deliver solutions for more sustainable agriculture.

“It takes 11 years of research and development and millions of dollars to bring a new crop protection product to market, which is why it is so important that existing products are used safely and sustainably,” he said.