Weed and Insect Communities in Wheat Crops with Different Management Practices

Abstract

Biotic adjustments to changes in crop management practices are reflected in the presence or absence of weed and insect populations. The pattern of response and the causes that drive them are important to reveal the main factors involved in molding the structure of an agroecosystem and its dynamics. In this study, weed and insect communities were characterized in wheat (Triticum aestivum L.) crops from the Rolling Pampas with different cropping histories. Surveys were performed in fields that were selected randomly from those located on highlands with typical Argiudol soils and cultivated with conventional tillage. Fields, weeds, and insects were classified with cluster analysis, and weed and insect associations were determined using agronomic variables with canonical correspondence analysis (CCA). The classification of the data resulted in six floristic groups and seven insect groups that characterized different weed and insect communities. Three weed and insect communities associated with the number of years with annual cropping after a pasture that lasted for several years, the duration of wheat crop cycle, and soybean as a preceding crop were identified.