Political efforts are made in the European Union (EU) to reduce pesticide use and to increase the implementation of integrated pest management (IPM). Within the EU project ENDURE, research priorities on pesticide reduction are defined. Using maize, one of the most important crops in Europe, as a case study, we identified the most serious weeds, arthropod pests, and fungal diseases as well as classes and amounts of pesticides applied. Data for 11 European maize growing regions were collected from databases, publications and expert estimates. Silage maize dominates in northern Europe and grain production in central and southern Europe. Crop rotations range from continuous growing of maize over several years to well-planned rotation systems. Weeds, arthropod pests and fungal diseases cause economic losses in most regions, even though differences exist between northern countries and central and southern Europe. Several weed and arthropod species cause increasing problems, illustrating that the goal of reducing chemical pesticide applications is challenging. Pesticides could potentially be reduced by the choice of varieties including genetically modified hybrids, cultural control including crop rotation, biological control, optimized application techniques for chemicals, and the development of more specific treatments. However, restrictions in the availability of alternative pest control measures, farm organization, and the training and knowledge of farmers need to be overcome before the adoption of environmentally friendly pest control strategies can reduce chemical pesticides in an economically competitive way. The complex of several problems that need to be tackled simultaneously and the link between different control measures demonstrates the need for IPM approaches, where pest control is seen in the context of the cropping system and on a regional scale. Multicriteria J. Appl. Entomol.

In growth room regimes arranged to simulate field conditions which coincide with natural infection of oilseed rape by Leptosphaeria maculans, leaf inoculation resulted in systemic infection. After colonizing intercellular spaces in the spongy mesophyll of the lamina, the fungus reached a vascular strand and spread down the petiole mainly in xylem vessels or between cells of the xylem parenchyma and cortex, eventually invading and killing cells of the stem cortex and causing the stem canker symptom. The intercellular systemic phase of growth, which was biotrophic and virtually sytnptomless, occurred under a wide range of temperatures.

The main source of Leptosphaeria maculans (Desm.) Ces. & de Not. infection on winter oilseed rape in Cambridgeshire was stubble debris from the previous season. Heavy leaf spot infection of seedlings near unploughed oilseed rape stubble resulted in complete crop loss. The fungus actively colonised stubble debris after harvest and perithecia were formed predominantly on tissues colonised during this period. Ascospores were detected throughout the year, mainly from October to April. The degree of leaf spot infection in the autumn was correlated with stem canker infection at the end of flowering and with severe stem lesions at harvest. The incidence of leaf spot infection was greater in the spring than in the autumn, particularly during the period of extension growth and early flowering. Stem canker infections were first seen in March and continued to develop up to and after harvest.

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