Herbicide-resistant weed species have become widespread in recent years. Fifty-five weed species, including 40 dicots and 15 grasses, are known to have biotypes resistant to the triazine herbicides. One or more resistant species have arisen in 31 states of the United States, four provinces of Canada, 18 countries in Europe, and Israel, Japan, Australia, and New Zealand. Resistance to other classes of herbicides is more restricted in distribution and recent in detection but is becoming more widespread. Trifluralin resistance has spread in the southeastern United States and has been detected in Canada, while 11 species with biotypes resistant to paraquat have been reported around the world. Diclofop-methyl-resistant weed species are problems in cereal production in Australia and have been found in Oregon, South Africa, and the United Kingdom. Resistance to the substituted ureas also is present in the United Kingdom, West Germany, and Hungary. Within the last 2 yr, biotypes of at least four weed species resistant to the sulfonylurea herbicides have arisen following several annual applications of these herbicides in wheat. Some resistant biotypes have multiple resistance to different classes of herbicides, which greatly exacerbates the threat of resistance. Herbicide resistance has reached the level where more concerted efforts are needed in research, education, and development of effective management strategies to preserve herbicides as essential tools of agricultural technology.

Introduction. This protocol aims at detecting and evaluating sensitivity shifts in Pseudocercospora musae (teleomorph: Mycosphaerella musicola) populations towards fungicides that are currently sprayed to control Sigatoka disease of banana. The principle, key advantages, starting plant material, time required and expected results are presented. Materials and methods. Necessary laboratory materials, and details of the seven steps of the protocol achieved during four days of experiments are described. Results. The protocol results in the observation of conidial germination of P. musae (pattern or germ tube elongation) according to the sensitivity to fungicides.

Kampimodromus aberrans is a predatory mite species present in vineyards of South of France and also in uncultivated areas, from where great densities disperse into the neighbouring vine fields, mainly by aerial means. In order to determine the origin of migrants in an experimental vine plot, a molecular study using RAPD markers was performed. It was found that there exists genetic differentiation of populations collected in the experimental vineyard, and those collected, both from surrounding cultivated and uncultivated areas. No correlation between genetic and geographic distances was found. Thus, despite the dispersal of great densities of mites into the plot, selection pressures may affect their settlement. To determine the impact of pesticide application on mite settlement, we studied the insecticide resistance of K. aberrans populations collected in the vine field and on an oak located in a neighbouring uncultivated area. The insecticide tested, quinalphos, is the most frequently applied pesticide in the plot. High resistance levels were observed in both populations. However, at the recommended concentration, mortality rates (80 and 87 %) were quite the same for the two populations. Thus, the application of this pesticide seems not to be the major explanation of the poor settlement of migrants coming from woody areas into the plot, and other studies have to be conducted to determine other factors involved.