Hygiene measures in greenhouse horticulture are increasingly being enforced nowadays. That makes sense, but it makes it more difficult to assess the disease and infestation level, according to Arno Moerman, Vegetable Growing Consultant at Koppert Biological Systems. "After all, consultants can no longer physically go into the greenhouse, because of the risk of transferring viruses, bacteria, et cetera. That means that we leave the scouting entirely to those responsible within the company."
Nevertheless, Koppert's advisers would like to have the best possible insight into what is going on in the greenhouse. "It is therefore becoming increasingly important that we scout and communicate uniformly, so that we actually talk about the same thing and do not assume that that is the case.
Recognizing isn’t the problem, providing good advice is a greater challenge
Recognizing diseases and pests is not the problem here; these are easy to assess based on photos. But when we cannot go into the greenhouse, it is complicated to determine the infestation level and the number of biological control agents that are present. For this reason we have to move towards a good, watertight and uniform system of scouting, to enable us to give sound advice."
It’s not that simple, Arno knows. "For example, when scouting white fly, by way of counting the number of white flies on the sticky traps, many factors play a role. Does everyone hang the traps in the same way? Does each company use the same number of traps per hectare and are these added up by everyone every week? And how is an infestation interpreted? While one entrepreneur judges that five to ten white flies per plant is quite a lot, the other does not even worry about it. And there are several more subjective factors."
It is therefore important that the grower, together with their adviser, draw up a good and clear scouting plan, says Arno. "This must above all contain clear rules for recording a disease or pest. If this is done correctly and unambiguously, then correct advice can be provided. In short: good scouting and communication are the basis for effective pest control."
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Koppert Biological Systems