Interfarm is advising growers to trial biological products to control damaging caterpillar pests as a substitute for insecticides.

The company is urging growers of vegetables, soft fruit, protected crops and ornamentals to trial them to observe their effectiveness.

Dr David Stormonth, technical manager for Interfarm (UK) which is an affiliate of Sumitomo Chemical Company, said: “Biological products could be seen as slightly quirky products, but actually they can offer a highly effective and easy to use solution for the control of damaging caterpillar pests. In fact they are just as easy to use as conventional chemical insecticides and are easy to integrate into a programme with conventional chemicals.

“Take DiPel DF for example. This is a bio-insecticide in that the active ingredient is produced from the naturally-occurring micro-organism Bacillus thuringiensis var kurstaki, referred to as “BtK”. It is a highly effective insecticide recommended on a wide range of vegetable, fruit and protected crops, with the major advantages of no maximum number of applications, no harvest interval, no residues and with a unique mode of action. And you apply it in exactly the same way as any other insecticide, mixing the recommended dose rate with sufficient water to give good coverage of the target crop,” says David. “It also offers the advantage of not having any resistance problems.”

Dr Stormonth explained that DiPel acts as a stomach poison on the target Lepidoptera pests. He said: “The larvae or caterpillars feed on the treated foliage and stop feeding rapidly, dying within 1 to 3 days of ingesting the product, just like many other insecticides. It stops caterpillars feeding very rapidly and, once dry, is very rainfast, so it is a good first spray. It is also useful applied at a time when its no residues would be beneficial, such as when fruit is setting and during picking.”