Amaranthus retroflexus L. - štir obični

Abstract

Amaranthus retroflexus is a cosmopolitan species which is widely distributed in 70 countries of the tropical and subtropical zone. It is considered to be the third most represented dicotyledonous weed species worldwide, due to its aggressive growth and vast seed production, as well as its high efficacy of water use, C4 mechanism of photosynthesis and its strong photosynthetic productivity. It is a typical weed in row crops, orchards and vineyards, but can also be found in fallow fields, on field edges and in ruderal habitats. Its harmful effects are expressed through its: 1) reduction in the yield quantity and quality, 2) production of allelopathic chemicals, which affect the crop health, 3) acting as an alternative host for pathogens and insects, 4) toxicity to livestock and 5) production of pollen, which causes allergic reactions in humans. The application of integrated weed management system in the case of this species implies the application of all available control measures (crop rotation, timely and adequate soil cultivation practices, crop protection, adequate fertilization, use of a well-burnt manure, timely application of highly efficient herbicides and the application of alternative control measures, e.g. natural and synthetic mulches, biological substances, physical and other available measures). Out of all of the aforementioned, the agro- technical measures and herbicides are the most often used control measures applied in intensive agricultural practice.