Crop protection

Herbicides are widely used in agriculture to control weeds that decrease cereal production and economic profits. A new control method is based on cultivation of Clearfield® wheat cultivars that are resistant to the imazamox herbicide. Scientists Rojano-Delgado et al. have evidenced several mechanims involved in  imazamox resistance.

Current control of pests in agriculture is done mainly using mineral fertilizers and toxic pesticides. Alternative solutions are thus needed due to concerns for public health, environmental protection, and development of resistant pests. Chitosan, obtained from exoskeletons of crustaceans and insects, showing both antimicrobial and plant-immunity eliciting properties. Agronomists Xing et al. explain that chitosan, a material obtained from exoskeletons of crustaceans and insects, can be used to enhance natural plant defenses. Chitosan also displays antimicrobial properties.

Plant diseases cause major economic losses for farmers worldwide. The Food and Agriculture Organization (FAO) estimates indeed that pests and diseases are responsible for about 25% of crop loss. To solve this issue, new methods are needed to detect diseases and pests early. Agronomists Martinelli et al. review advanced detection methods such as novel sensors that detect plant odours, and spectroscopy and biophotonics that are able to diagnostic plant health and metabolism.

Rice sheath blight is a disease caused by the fungus Rhizoctonia solani. This disease induces up to 36% of loss of rice production. This problem is particularly high in the Amazon region under tropical conditions where irrigated rice is cultivated by small farmers on the rivers banks. Scientists França et al. have designed a sustainable way to control sheath blight by application of the fungus Trichoderma sp.

European farmers should adopt integrated pest management from 2014. Indeed, applying the principles of integrated pest management and organic farming should lead to a more sustainable agriculture with less pesticide. Lefebvre et al. designed a framework to understand what incentives encourage farmers to adopt integrated pest management. Their findings help to understand farmer reaction to policy incentives. Results also show how should public money be used to favour sustainable agriculture.

The production of cucumber, melon and watermelon is highly decreased by the root-knot nematode – a kind of worm – that causes dramatic galling on the roots of cucurbitaceous plants. A potential solution is to graft susceptible plant scions on nematode-resistant rootstocks. Liu et al. found a new grafted rootstock resistant both to root-knot nematode and to Fusarium wilt, another pest.

The glasshouse whitefly Trialeurodes vaporariorum is major worldwide pest of glasshouse crops. It does its damage by excreting plant sap which then grows black sooty mold fungus which spoils the appearance of the product. Tosh et al. reasoned that since plant volatiles – the odour of a plant – are usually harmless to humans but often harmful to insects, and since the glasshouse is an enclosed space, plant volatiles could be used to control whiteflies. The authors attempted to apply the well know ‘confusion effect’ – confusing animals with too much information – by bombarding the whiteflies with a super-abundance of host plant volatiles while they are feeding on tomato plants. Unfortunately the confusion effect does not have a strong impact on the whitefly. The confusion effect may be used in combination with other odour-based control methods for the glasshouse whitefly, but it is unlikely to be sufficient as a stand-alone control method.

Food security is increased and poverty is reduced in sub-Saharan African by cultivation of fruits and vegetables. However, up to 100% yield losses are due to insects and diseases. Misuse, overuse and use of unauthorized pesticides are common among small farmers. De Bon et al. presents solutions based on agroecology and integrated pest management (IPM) to reduce pesticide use. In particular ecological methods and good pesticide management should be taught to farmers and other stakeholders.

Flavescence dorée is a serious disease that causes major yield losses for European viticulture. Flavescence dorée is still spreading in Europe despite mandatory controls using insecticides. Vine infection by Flavescence dorée is done by the association of a phytoplasma – a bacterial parasite – and the leafhopper Scaphoideus titanus. The only actual solution to avoid the disease is to control the leafhopper. Chuche and Thiéry review the biology and ecology of the S. titanus leafhopper to highlight potential ecological remedies. Innovative techniques include symbionts, mating disruption and push-pull strategies including antifeedants