Research results in cucumbers

A lot of experience has been gained with the predatory mite A. swirskii in cucumber cultivation. In 2003, WUR Greenhouse Horticulture began research into new natural enemies for thrips in cucumber crops. Ten types of predatory mites were screened, and A. swirskii scored particularly highly. Compared to the standard predatory mite Amblyseius cucumeris, A. swirskii was many times more effective in combating thrips and reached very high population densities in a much shorter space of time. When releasing both

A. cucumeris and A. swirskii, A. cucumeris is in many cases completely ousted by A. swirskii (graph 1).

See graph 1 A. swirskii predatory mites oust A. cucumeris.

The discovery that A. swirskii is effective in combating thrips makes this predatory mite instantly of great interest with regard to cucumber crops, since it had already been demonstrated in the past that the predatory mites can also combat whitefly. The effect of A. swirskii on glasshouse whitefly has been demonstrated very clearly in greenhouse trials. Compared with an untreated situation, the population of the glasshouse whitefly was reduced by approx. 90%. However, in a situation in which only glasshouse whitefly and A. swirskii are present, the predatory mite was unable to offer sufficient protection for the entire cucumber cultivation period. Interestingly, in situations in which both glasshouse whitefly and thrips were present, both these pests were controlled very well.

Various practical trials in cucumber crops have demonstrated that A. swirskii is also able to reach good population levels quickly during short cultivation periods and therefore to control thrips and whitefly effectively. In cucumber crops grown in illuminated greenhouses, which generally have more problems with whitefly, A. swirskii stands its ground well and keeps whitefly and thrips under control.

If we put all the research results together, it becomes very clear that A. swirskii represents real added value for cucumber cultivation. A. swirskii considerably improves the possibilities for combating infestations biologically during short summer cultivation cycles as well.

• A. swirskii can establish itself very well in cucumber crops In 2005, the experimental vegetable cultivation garden in Sint-Katelijne-Waver (Belgium) also carried out research in collaboration with Koppert into ways of combating thrips and whitefly. This showed the positive effect of A. swirskii in combating both infestations.
• A. swirskii combats thrips more effectively than A.cucumeris
• Together with the parasitic wasps, A. swirskii works well in combating whitefly