Crop protection

Preserving remnants of the forest in agricultural landscapes supports biodiversity conservation and the provision of agriculturally-relevant ecosystem services such as pollination or biological control. In Brazil, scientists Medeiros et al. recently found that forests in the surrounding landscape reduce the occurrence of a widespread economic pest in sun-coffee monocultures by enhancing natural enemy diversity. Remnants of the forest maintain a permanent reservoir of natural enemies and therefore, these habitats should be protected.

Inter-cropping non-Bt-maize with legume crops increases the role of predatory arthropods in naturally regulating herbivorous arthropod pests. Scientists Nickson Otieno et al. recently observed stronger predator-herbivore interactions within maize intercropped than in monoculture fields, both in organic and conventional farming systems. The results are useful in prescribing field practices for sustainable small-scale agriculture from sub-Saharan Africa.

Smallholder farmers in low-income countries often use plant extracts (‘botanicals’) to prepare homemade pesticides. This practice has remained controversial due to a perceived lack of evidence that such home remedies are effective and safe. Scientists Dougoud et al. reviewed commonly used botanicals and found evidence that they can reduce pests and crop damage. However, results are highly variable, depending on how the homemade pesticides are prepared and used.

Xanthomonas wilt is a devastating disease causing great yield losses to banana producers. Scientists Uwamahoro et al. identified several factors influencing disease occurrence in Rwanda: agro-ecological locations, farming practices, farmers’ knowledge, application of disease management strategies, and information distribution channels. The understanding of such factors will facilitate the development of sustainable methods to manage Xanthomonas wilt.

Enhancing natural enemies to control pests in apple orchards is an alternative to using pesticides. Scientists Salliou et al. compared what the stakeholders perceive to be the impact of different strategies developed to enhance natural enemies. They identified greater expectation from biological control with habitat management within orchards than from engineering the surrounding landscape.

Weeds represent an important obstacle to wheat production, particularly in low-input and organic systems. Scientists Lazzaro et al. combined genetic with agroecological approaches to study weed competition related traits in wheat. They show the high potential of interdisciplinary research for selecting more competitive wheat cultivars as valid support to sustainable integrated weed management.

Worldwide crop production sustainability is threatened by weed resistance to herbicides. Scientists Mascanzoni et al. demonstrated in Italy that a high risk of resistance evolution is associated with traditional rice cultivation systems opting for monoculture, water-seeding, and less diversified herbicide strategies. They showed that dry seeding and crop rotation rate are negatively correlated with resistance occurrence.

Scientists Baraibar et al. showed that in the fall, early planting resulted in larger weed biomass in all cover crop types, but grasses and mixtures were more weed suppressive than legumes and brassicas. In the spring, cover crops with large biomass consistently limited weed growth. Their results may help farmers achieve multifunctional cover crops coping with production and conservation.

Weedy rice is one of the worst weeds worldwide, capable of severely decreasing yield in rice fields. Scientists Gao et al. recently showed that combine harvesters are major agents of weedy rice seed dispersal within fields and across rice-growing areas. They recommend that fields severely infested with weedy rice should be harvested separately in order to avoid accumulation of weed seeds in the combine harvester and their subsequent dispersal.