Field simulated contact toxicity

To place the contact toxicity of pesticides briefly in a historic framework, two protocols are described briefly. In Stute (1991), the contact toxicity of PPPs applied as a spray, was assessed by exposing the bees to a 150 cm2 paper, contaminated with twice the recommended field application rate of the target pesticide. The PPPs to be applied in a dusted form were administered using a Lang-Welte-Glocke to cover the surface completely and homogeneously. Johansen (1978) assessed the contact toxicity by placing bees in a bell-jar duster loaded with 200 mg pesticide and administered the pesticide onto the bees via vacuum and subsequent imploding incoming air to disperse the pesticide homogeneously over the bees. Both the Stute (1991) and Johansen (1978) tests provide general information about toxicity. However, in both cases the amount of the PPP actually administered to the bees was unknown. This makes it hard to do further calculations about risk assessment. The other two methods imitating field contact exposure are described in section 3.2.3.