The weather has a great influence on plant protection products. Not only during the application of a product, but also before and after. During the fifth course day of the Agricultural Sprayer Academy (ASA), the influence of the weather was central. How do plant protection products work under different weather conditions?
Erno Bouma is an agricultural meteorological specialist and teaches the fifth course of the ASA. He talks about the influence of different weather conditions on the application of plant protection products. The most suitable application moments for the different types of resources are also discussed.
Weather conditions
The weather affects the operation and effectiveness of plant protection products. And different weather conditions are desirable for the different plant protection products. For example, the temperature influences the effect of fungicides. A lower temperature ensures that the fungicide works longer both preventively and curatively. At the time of application it is of course important that the fungicide can dry properly.
The moment of spraying is also important for an insecticide for a better effect. The effect of a contact insecticide is best at a somewhat higher temperature, because the insects are more active then. A suitable time to apply an insecticide is therefore early in the evening. Then the temperature is still in the crop and the insects are still active. In the evening there is little radiation anymore. Irradiation can cause damage to the crop at the time of application.
When applying a herbicide, growing conditions are important. A contact herbicide works better if a plant's wax coating is thinner. The wax layer is thinner when it is 'growing weather'. That is a broad concept that depends on the period in a growing season. Under growing weather conditions, the wax layer is thinner. Under less favorable weather conditions, the wax layer is thicker. The wax layer also makes a melde difficult to combat. This already has a thick layer of wax that is difficult to penetrate.
Composition medium
Furthermore, the composition of a plant protection product was discussed during the course. For example, a water-based agent (glyphosate) needs more time to penetrate the plant than an oil-based agent. The weather also influences this. After a period of favorable weather, the water-based products have a much faster effect. Transport in the plant is then faster as the water management is better organised. The transport in the plant also depends on the agent. A systemic fungicide will only remain in the leaf layer into which it landed. In contrast, foliar fertilizers or a systemic herbicide will spread throughout the plant.
The conclusion is that weather conditions are important for the application of plant protection products. This applies to the weather before, during and after spraying.
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