Within the concept of IPM, chemical pesticides are mainly used as a corrective measure. Nevertheless, the following guidelines should be respected:
- Use selective pesticides. These are pesticides that are non-toxic or only slightly toxic to beneficials or do not inhibit their development or reproduction.
- Use selective application techniques. Some pesticides may be applied without actually damaging the beneficial population, even if they are not particularly safe for beneficials. This can be achieved by applying pesticides through the drip system, drenching, using seeds treated with a seed coating, and restricting applications to young plants.
- Use pesticides with a short persistence. Some chemicals are quite harmful at the moment of application, but the effect may not last more than a couple of days. Soon afterwards, beneficials can be introduced again, or natural enemies from the surroundings can enter in the treated area again and survive.
- Ensure that the plant propagator does not use pesticides with a long persistence. These products can stop or inhibit the development of beneficials.
- Avoid the use of pesticides with a long persistence prior to beginning biological control.
- Consult the Koppert Side-Effects Guide for detailed information about the compatibility of pesticides with most beneficials and the persistence of a possible harmful effect. This guide is also available on the Internet 'Koppert's Side Effects Database On-line'.
- Avoid dusting any products, as dusting inhibits the development of beneficials.
- Be aware that pesticides or their vapour may drift from the area of application into an area with biological control. When this happens, the population of beneficials can be affected. During spot treatments, screen off the infested area if possible. Proper communication with neighbours in combination with the right action (open/close vents, avoid spraying under windy conditions) can mitigate these effects.