Crop protection

The growing herbicide resistance of weeds in conjunction with societal concern about the adverse effects of herbicides on the environment compel us to seek out sustainable cultivation systems that are less dependent on chemical crop protection agents. To decrease the use of herbicides while simultaneously preventing the growth of weed populations, we are working on integrated weed control systems. These systems are based on knowledge about weed biology and the ecology of crop-weed interactions.

The variability of weeds in space and time can be tackled through the use of new advances such as vision technology. Intelligent combinations of crop rotation, physical and mechanical control methods and dispensing herbicides through smart application techniques are all part of our ongoing research.

Integrated pest management (IPM) is the term used to describe an optimum combination of farm management measures designed to produce healthy crops. When growing agricultural and horticultural products, farmers are obliged to deal with harmful insects, mites, gastropods and other pests. Damage from insects reduces both the quality and quantity of the yield.

IPM forms the backbone of our approach at Wageningen Plant Research: which measures must be introduced when, and how do you do this efficiently? Infestation depends on the population density and the favourability of the conditions in which they are able to develop. Weather, climate, farm management measures, crop choice and natural enemies are all factors that affect the ability of pests to develop. The character and resilience of the affected plants are factors that determine the economic damage the pests cause. All species of plants have their own defence mechanisms. Expertise about crops and pests, and knowledge of practical conditions, enable us to deploy targeted research methods.

Wageningen has in-house expertise for all relevant pests in agricultural and horticultural crops, and maintains both national and international networks. Three of the most important groups of pests are: soil pests, flies and sucking insects.

Research shows that an integrated application of prevention, mechanical and biological control and occasionally targeted chemical crop protection is currently the most effective way to protect crops against pests and diseases. Within this so-called ‘integrated pest management' glyphosate plays an important role. Glyphosate blocks in plants the formation of certain enzymes. This kills weeds that are not resistant. By targeted application once every 6 or 7 yearsin a multi-year approach, perennial weeds are effectively controlled. An additional advantage is that less mechanical tillage is needed in the remaining years. This is beneficial for the soil, because a healthy and erosion-resistant soil benefits from as little tillage as possible.

The toxicity of glyphosate to humans and the environment has been studied for years. It is known - if applied selectively - to be safer than other pesticides. Plant protection products must also meet safety standards. The CTGB ensures that these requirements are met.

Research is also being conducted within WUR into possible effects of glyphosate on the environment. For example, the extent to which glyphosate is found in agricultural soils has been examined. Data from more than 300 soil samples from agricultural soils in several European countries showed that glyphosate and AMPA (the most stable breakdown product of glyphosate) were found in 45% of these samples. The concentrations of AMPA found were higher than those of glyphosate. The highest measured amount of AMPA was 2 mg per kilogram of soil. There is no official standard for soil; for drinking water, the maximum standard is 0.1 µg per litre. To what extent this has negative effects on soil biodiversity, aquatic life and humans is the subject of research.

Biological control can play a major role in a resilient cultivation system, by using natural enemies of fungi, bacteria and pest insects. It is possible to design a cultivation system that is largely able to contain diseases and pests on its own with biological control. This largely dispenses with the need for chemical crop protection.

Researchers of Wageningen University & Research study all the organisms in the system, from micro-organisms such as fungi and bacteria, to macro-organisms such as predatory mites and parasitoid wasps.