Prüfung der initialen Wirkung sowie der Schadwirkungsdauer von Pflanzenschutzmitteln auf Eiparasiten der Gattung Trichogramma

1998

S. 53-67

44 Lit. Ang.

Unselbständiges Werk

200100329

The Working Group "Pesticides and Beneficial Organisms" of the International Organisation for Biological Control (IOBC), West Palearctic Regional Section (WPRS) recommends a combination of several laboratory, semi-field test methods to assess the side effects of pesticides on beneficial arthropods. The choice of methods was made to screen out harmless preparations using a worst case method at the beginning of the sequential testing, harmless preparations are not tested any further. In the present study, three types of methods were carried out to test the side effects on Trichogramma (Hym., Trichogrammatidae): (a) laboratory initial worst case toxicity test at the highest recommended concentration of the product on the adult parasitoids, the most susceptible life stage. This is tested by exposing the adult parasitoids to fresh dry pesticide film applied on glass plates, (b) laboratory, less susceptible life stage, spraying of product on parasite pupae within the host eggs, (c) duration of harmful activity, exposure of adults to pesticide residues applied on plants at intervals after treatment. This combination has the advantage of including two different developmental stages of the natural enemy (adult and pupa) that greatly differ in their susceptibility and vulnerability to pesticides. The persistent test (duration of the harmful activity) adds information towards the overall impact of the chemical on the natural enemy. The results of the experiments with a total of 161 preparations (66 insecticides/ acaricides, 53 fungicides, 42 herbicides) revealed that 17 insecticides/ acaricides, 34 fungicides and 27 herbicides were harmless to Trichogramma adults. 23 insecticides/ acaricides, 19 fungicides and 7 herbicides were shown to be slightly to moderately harmful to the adults, but only harmless to slightly harmful to the host egg. The persistence test demonstrated, with 71 preparations that were harmful to the adults, that 7 were short lived (< 5 days effect), 13 slightly persistent (3-10 days) 22 moderately persistent (10-24 days) and 29 persistent (> 30 days). The value of the combination of tests used to compare between the side effect of different preparations is emphasised.