Tomato production is threatened by the tomato borer Tuta absoluta, notably due to the development of resistance in strains treated with conventional insecticides. Agronomists Borgi et al. show that the Beauveria bassiana fungus can be used efficiently against the tomato borer. Fungal strains overproducing the protease and chitinase enzyme are suitable biocontrol agents.
Perennial crops are plants that live for more than two years. They reduce fertilizer input and soil erosion, and favor carbon sequestration. However perennials are declining due to soil pests and pathogens. Vukicevich et al. propose to use cover crops to select soil microbial communities that will benefit perennial crops.
Sustainable agriculture should tend to reduce or stop the use of pesticides. However, this absence of chemical control may affect harvest quality by leading to an increase of fungal toxins, named mycotoxins, due to the development of pathogenic fungi in maize, for instance. Agronomists Reboud et al. studied mycotoxin levels in 29 maize fields over 4 years in France. They found mycotoxins levels twice higher in untreated fields, of cumulated 3.7 mg/Kg on average, versus pesticide-treated fields, of 1.9 mg/Kg. However, mycotoxins levels in untreated fields were still about 50% lower than the acceptable legal level for edible maize but with reduced safety margin.
Damage on fruit production depends on the nature and movement of insects. However little is known on the year-round movements of insect predators in fruit crops and surrounding non-crop vegetation such as cover crops and edge plants. Agronomists Sorribas et al. showed that insect biodiversity was highest in organic managed farms. Nonetheless, insect abundance was highest in integrated pest managed systems. Numerous insect species moved from the crop toward edge shelterbelts to overwinter, because shelterbelts were largely preferred over cover crops. As a consequence, control strategies should focus on enhancing flying predators in shelterbelts.
A mycotoxin is a toxic metabolite produced some fungi, commonly known as molds. Mycotoxins contaminate maize and food, and thus pose a serious health risk. The factors favoring mycotoxin contamination are poorly known. A study by Liu et al. show that the main factors for contamination include less strict receiving and inspection criteria, inappropriate storage conditions and poor processing practices. The critical control points for mycotoxin management in the supply chain of maize and maize-based feed, are feed mill receiving, storage and feed processing.
Potato late blight, caused by Phytophthora infestans, is one of the main diseases in potato production, causing major losses in yield. Potato late blight is presently controlled by toxic fungicides. There is therefore a need for safer strategies. Agronomists Pacilly et al. used fuzzy cognitive mapping, a modeling technique, to understand the biological, physical and social factors influencing late blight development, and, in turn, to propose the best management scenario.
The olive moth is a major pest of olive trees, causing up to 40% fruit fall. A potential solution is to use the common green lacewing because its larvae is a voracious predator of the eggs of the olive moth. But how to favour the abundance of green lacewings? Scientists González et al. found that flowering plants such as pignut, wild fennel, honeysuckle and wild asparagus are food resources that increase the longevity and fecondity of green lacewings.
Industrial farming with intensive breeding has deprived most crop food varieties of their resistance to pests, diseases and climate stresses. Wild relatives of these crops may possess genes that confer enhanced resistance. Such genes of resistance can subsequently be introduced into commercial varieties. McDaniel et al assessed a wild species of tomato for resistance to the glasshouse whitefly. They found several resistance mechanisms present in the wild tomato that are potential targets for introduction into the commercial tomato genome.
Herbicides have been used for decades to control weeds in crop fields. However, a such strategy fails in the long run because weeds, as any living organism, adapt and modify their metabolism to tolerate the toxic chemical. Scientists Fernandez et al. have evidenced the first case in France of glyphosate-resistant weed in the species Lolium rigidum. They also found that this smart weed has not developped only one, but three different defense mecanisms in weed genes.
Most classical pesticides are now found in almost every media such as water, air, food and drinks, thus threatening human health. Moreover, those pesticides are inefficient in the long run because pests adapt to pesticides fast. There is therefore a need for guidelines explaining how to reduce pesticide usage and develop new strategies. Barzman et al. propose eight principles of integrated pest management (IPM). They show in particular that the complexity of farming systems can improve pest management.
