Popular canola seed treatments equal in efficacy against aphids

A recent study conducted by cesar and Advanta Seeds has found three popular neonicotinoid insecticide-based canola seed treatments offer the same protection from green peach aphids (GPA), and that the coatings offer superior protection compared to no treatment.

The research, headed by cesar director and entomologist Dr Paul Umina, showed no significant differences between Cruiser Opti, Poncho Plus and Gaucho seed treatments, and all conferred high levels of protection against GPA for up to eight weeks after seedling emergence.

Additionally, seedlings treated with Cruiser Opti, Poncho Plus and Gaucho showed lower plant damage than seedlings in the untreated controls.

The trial was conducted by the research team using a microcosm approach under shade-house conditions over a five month period.

Advanta Seeds canola business manager Justin Kudnig said the results were timely given the impact the pest had on southern canola growing regions in recent years.

“Following GPA’s contribution to the costly outbreak of Beet western yellows virus (BWYV) in southern Australia in autumn-winter 2014, Advanta Seeds worked with cesar for the first time to clear up any confusion on seed treatments and their role in suppressing GPA,” he said.

Mr Kudnig said the research partnership was a significant first step in the company’s ongoing research into integrated pest management (IPM), one of six fields currently under investigation under its wider Innovative Cropping Solutions (ICS) banner.

“Our ICS team investigates industry issues by conducting professional, technically sound research and providing advice, recommendations and realistic economic solutions for growers, consultants and agronomists throughout Australia.”

The green peach aphid (Myzus persicae) is an important pest of a variety of broadacre crops and controlling it relies heavily on the application of broad-spectrum pesticides.

However, resistance in GPA to multiple chemical classes, including carbamates and synthetic pyrethroids, is widespread across Australia, and appears to be increasing.

The cesar team has recently discovered field populations of GPA that have evolved resistance to neonicotinoid insecticides.

Dr Umina said though the trial results were convincing, it was important to note the trial was conducted on aphid ‘biotypes’ that have no insecticide resistance.

“The efficacy of some insecticide seed treatments could be considerably lower against field populations of aphids with resistance,” Dr Umina said.

He said the trial was also conducted under ‘semi-field’ conditions; therefore the length of protection observed may not necessarily correlate to all field situations and growing conditions.

“Monitoring of seedling canola crops is recommended even when using insecticide seed treatments on canola. This is particularly the case in seasons that follow considerable summer rainfall, which tends to provide a green bridge of weed hosts for aphid survival.”