New insecticide, Actara, will provide potato growers with rapid knockdown of aphids, and at least three weeks of persistence, according to manufacturer Syngenta.

Belonging to the neonicotinoid class of insecticides, active ingredient thiamethoxan controls all four aphids [see box] important in the potato crop, including strains of Myzus persicae resistant to other insecticides, the firm’s Jon Ogborn (pictured below) said at a press launch of the product at British Potato 2007.

“It also, uniquely, has a label recommendation for virus reduction.”

Actara had contact, stomach and systemic properties, he explained. “Knockdown activity is as fast, if not faster, than any of the new generation insecticides [such as Teppeki, Biscaya and Plenum].”

In fact, speed of kill was so quick, it wasn’t necessary to tank mix a pyrethroid, although mixing with one such as Hallmark Zeon, would give repellent activity discouraging aphids from flying in.

Its strong systemic properties meant it also protected new growth, as well as taking out aphids feeding on the undersides of leaves that might not be sprayed directly, he said.

Seed potato growers were advised to use the product as the first application in the programme, to clean out aphids from the crop, before moving into other products with a different mode of action, such as Plenum and Aphox during flowering. Actara could be used as the final spray in the programme to minimise survival of aphid colonies, he suggested.

Ware growers should use Actara if they saw high numbers of aphids in crops; otherwise he advised the use of Plenum. One application of Actara could see growers of varieties, such as Nadine and Russet Burbank that are susceptible to the effects of virus infection, through the early stages most vulnerable to early virus spread, according to his colleague Bruce McKenzie (pictured).

Trials suggested Actara programmes were as effective as the current standard, Hallmark Zeon, in reducing virus symptoms.

Only two sprays of Actara can be made in any one season in seed crops, and one in ware crops. Technically growers could use alternative neonicotinoid insecticides in the programme and exceed Insecticide Resistance Action Group guidelines for their use.

But to remain within the spirit of the guidelines for resistance management growers shouldn’t make more than two applications of any neonicotinoid insecticide in seed crops, Mr Ogborn said.

Actara will be “price-competitive” among other new generation insecticides, Mr McKenzie said.

It was so far only registered for potatoes in the UK, although it was being looked at either as a straight or in co-formulation for other crops, he added. The active ingredient is already available as a seed treatment for sugar beet.