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.

BackgroundRecent progress in selective breeding of maize (Zea mays L.) towards adaptation to temperate climate has allowed the production of inbred lines withstanding cold springs with temperatures below 8 °C or even close to 0 °C, indicating that despite its tropical origins maize is not inherently cold-sensitive.ResultsHere we studied the acclimatory response of three maize inbred lines of contrasting cold-sensitivity selected basing on multi-year routine field data. The field observations were confirmed in the growth chamber. Under controlled conditions the damage to the photosynthetic apparatus due to severe cold treatment was the least in the cold-tolerant line provided that it had been subjected to prior moderate chilling, i.e., acclimation. The cold-sensitive lines performed equally poorly with or without acclimation. To uncover the molecular basis of the attained cold-acclimatability we performed comparative transcriptome profiling of the response of the lines to the cold during acclimation phase by means of microarrays with a statistical and bioinformatic data analysis.ConclusionsThe analyses indicated three mechanisms likely responsible for the cold-tolerance: acclimation-dependent modification of the photosynthetic apparatus, cell wall properties, and developmental processes. Those conclusions supported the observed acclimation of photosynthesis to severe cold at moderate chilling and were further confirmed by experimentally showing specific modification of cell wall properties and repression of selected miRNA species, general regulators of development, in the cold-tolerant line subjected to cold stress.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-016-2453-4) contains supplementary material, which is available to authorized users.

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Maize is a cold-sensitive species, but selective breeding programs have recently succeeded in producing plants strikingly well adapted to the cold springs of a temperate climate, showing the potential for improved cold tolerance. The aim of the present study was to determine whether the adaptation of some inbred lines to spring chills is due to their increased true cold tolerance or whether it only represents an avoidance mechanism, which was the sole mode of adaptation during early stages of agricultural dispersal of maize towards higher latitudes. By characterizing numerous physiological features of several lines of different cold sensitivity, we show that a combination of both avoidance and tolerance is involved. A novel avoidance mechanism was found that favored unhindered development of the photosynthetic apparatus through protection of the shoot apex below soil level due to a shortened mesocotyl. It seems to be mediated by increased seedling photosensitivity at early growth stages. True tolerance involved improved protection of the cell membrane against cold injury at temperatures close to 0 °C and stimulation of light-induced processes (accumulation of anthocyanins, carotenoids, and chlorophyll, proper development of chloroplasts) at temperatures in the range of 10–14 °C, likely also related to the increased photosensitivity and mediated by gibberellin signaling.

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