Poor control of leafhoppers and aphids has led to just such a scenario. The use of thiacloprid (Calypso) against leafhoppers mid-season killed biological control agents, resulting in secondary problems with western flower thrips. This led to thrip populations being carried over to the following season, causing damage. HDC project PC 295 was commissioned to find IPM-compatible control measures for leafhoppers and aphids in commercial pepper crops.
With the loss of IPM-compatible buprofezin (Applaud) from the market in 2008, the hunt was on for a replacement. Luckily indoxacarb (Steward) was approved for caterpillar control just before the project and proved to be effective and compatible with many of the beneficials used in peppers. It should be applied at high volume to the point of runoff.
For organic growers, natural pyrethrins (Pyrethrum 5EC) will control leafhoppers but may have an adverse effect on Orius spp predators so should be restricted to leafhopper hot spots.
For aphids, Pyrethrum 5EC and Savona can be used as a secondary control measure to support primary biological agents. However, appropriate parasitoids should be released from planting and tailored to suit each cropping situation. If required, apply secondary treatments at high volume when aphids are just starting to cause sticky patches on leaves on fruits.
For details on all HDC activities, visit www.hdc.org.uk.