With increasing pressure on crop protection products, growers need new products and strategies to control pests in an effective way. Early 2015, Christiaan Bot of Arend Roses introduced the predatory mite Euseius gallicus, also known as Dyna-Mite® G-System on four hectares of roses in Maasland (NL). He has high hopes that this will prove to be a sustainable addition to his integrated pest management strategy: “You need a large army ready to fight thrips and whitefly. Gallicus settles well and develops as expected. The challenge is to continue this strong start.”
Unlike other predatory mite species, gallicus settles well in rose which is generally considered a really difficult crop for predatory mites. With continuous feeding the population grows explosively. Hence, there is no need to keep releasing new predatory mites. Christiaan explains: “We introduced gallicus in two rounds with a one week interval. This helps create a mixed and, therefore, a stronger population. Population growth was very fast. Within four weeks it became very easy to spot predatory mites. After two months, we had a mite on almost every leaf. It all goes according to plan and we are very pleased with the results. I see a good future for this approach.”
Monitoring and good advice
As long as there are no thrips or whitefly in the crop, the predatory mites are fed every week with NutrimiteTM. When the pests appear, the feeding is reduced, so that the predatory mites focus on the insects. It is crucial to continuously monitor the pest pressure in the greenhouse. We can respond immediately to what happens in the crop and that is surely a prerequisite for success. Every week, we discuss the scouting results with our advisors Arjan Spaans and Guido Halbersma of Van lperen. Also Marcel Verbeek and Juliette Pijnakker of Biobest think along with us. Together, we determine what are the next steps to achieve optimum results.
Strong return on investment
Arend Roses’s reasons to start with Dyna-Mite® G-System were not only technical. Economic considerations played a key role. “It is a considerable investment, but one that is expected to provide a good payback. With a beneficial that settles in the crop, continous releases are no longer required. We saw the predatory mites adapt to the circumstances and become more and more resilient. This season, we managed to limit the number of chemical corrections and to use only integrated correction products. Hence we were able to keep a large part of our Euseius gallicus. A limited introduction after the summer was sufficient to maintain the population at a high level.”
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