J. Pestic. Sci., 32(1), 1–9 (2007)

Pests, diseases and weeds of major food crops are currently controlled in the European Union (EU) mainly with the use of plant protection products (ppps) which offer, in many cases, the only satisfactory method of limiting yield losses. Efficacy in its first simple approach is the ability of a pesticide to fulfill the claims on the proposed label. It is expressed in terms of a) the extent of decrease of a pest population occurring on the crop and b) the protection of the yield, quantity and quality against damage caused directly or indirectly by the pest organism concerned. However, several additional elements were listed for the first time by the Food and Agriculture Organization (FAO) in 1985 and later on, by the European and Mediterranean Plant Protection Organization (EPPO), for consideration of the experimentation and evaluation of efficacy data. Efficacy, as defined by EPPO, is an equation in which the positive effects of treatment in performing the desired plant protection activity (effectiveness) and any other useful effects, are balanced against the negative effects (such as direct damage to the crop/phytotoxicity, or toxicity to beneficial organisms). Efficacy evaluation, carried out by regulatory authorities, intends to limit unnecessary pesticide exposure of users/bystanders and impact on the environment that might occur due to ineffective pesticides or unnecessarily high rates and application frequencies. The term “efficacy evaluation” is synonymous with the term “biological evaluation.” Efficacy evaluation at the EU level is mainly based on the data produced and submitted by the notifier and presented in the form of a ‘BioEfficacy evaluation of plant protection products at EU level: Data requirements and evaluation principles