Caesar AustraliaPress release, September 2, 2022
The resistance of the green peach aphid (Myzus persicae, GPA) to many groups of chemical modes of action makes it an ongoing management challenge. In Australia, GPA has developed resistance to synthetic pyrethroids, carbamates, organophosphates, neonicotinoids and, most recently, sulfoxaflor.
And now, Australian researchers have found GPA populations resistant to spirotetramat, the active ingredient in Movento® 240 SC insecticide, as well as several generic products containing the same active ingredient. Spirotetramat, a Group 23 insecticide, is an important tool in the management of GPA in vegetable crops in Australia.
This discovery was made through collaborative research between Cesar Australia and the University of Exeter (UK), led by Associate Professor Paul Umina, Director of Cesar Australia, a Melbourne-based scientific research organization. The research was a co-investment by Bayer Crop Science and the Grains Research and Development Corporation (GRDC).
“Resistance to spirotetramat has been confirmed in a small number of GPA populations collected from Queensland vegetable crops, and importantly, this resistance has been shown to persist after several generations of culture in the laboratory, demonstrating that there is a basis underlying genetics,” Associate Professor Umina said.
Spirotetramat resistance in GPA has not been found in any other country, although this product is widely used to manage GPA in a range of cultures around the world.
“Clearly there is something we are doing in Australia that is breeding for resistance in this species, which really should be looked at,” says Associate Professor Umina.
Troy Mulcahy, Market Development Agronomist at Bayer Crop Science based in Victoria, recommends that Movento® be applied early before pest numbers build up. “For best results, Movento® should be applied in two sprays 7-10 days apart to target a single generation of aphids for more effective control,” says Mulcahy.
Research has shown that the right adjuvant (eg Agridex®, Hasten®) is essential to achieve high level pest control when using Movento®. Without the correct adjuvant, product performance will be poor.
“Full coverage is also essential so spray booms should be installed to deliver the chemical to where the aphids are and growers should be careful of dust and honeydew on the leaf as these factors can all reduce product performance.” said Mr. Mulcahy.
High water volumes, correct nozzle selection and appropriate ground speeds will help ensure that Movento® performs as expected. It is essential that the full label rate be used, as lower rates will often be insufficient and will only serve to increase the selection pressure for additional resistance.
“We know from this research that the resistance mechanism present in these GPA populations results in cross-resistance to other Group 23 insecticides,” says Mulcahy.
In order to limit the spread and to restrict the further development of resistance, it is important that Movento® and other Group 23 insecticides are used responsibly as part of insecticide resistance management.
“While Movento® remains a very effective means of controlling GPA in many parts of Australia, this finding serves as an important reminder to use the product wisely,” says Associate Professor Umina.
For a species like GPA, which has a high propensity to develop new resistance, this means spraying insecticides only when absolutely necessary and alternating between insecticides of different modes of action in cases where multiple sprays are needed in one go. single season.
Growers are urged to closely monitor their crops this year and contact their local Bayer Crop Science Territory Manager if unsatisfactory aphid control is observed after application of Movento®.