Practical experiences
A. swirskii has been released on increasing numbers of enterprises in varying dosages since 2005. Due to the enormous leaf surface in roses, the predatory mites have to cover great distances before coming into contact with their prey if levels of whitefly are low. It appears that A. swirskii avoids greasy spots caused by honeydew from whitefly. For this reason, it is important to start using A. swirskii straight away in cases of slight whitefly damage. For growers who tolerate higher levels of whitefly infestation, A. swirskii will become easier to trace in the crop. This indicates that whitefly are a good source of food, on which the predatory mites thrive.
The focus was on combating whitefly. It is clear that A. swirskii reduces the whitefly population. However, the total system of predatory mite, whitefly-targeting parasitic wasps and chemical correction agents still needs to be optimised. The predatory mite is also found regularly in small spider mite hot-spots.
The effect of A. swirskii on thrips appears to be significantly greater than that of A. cucumeris. The number of chemical interventions can be reduced further thanks to the contribution of A. swirskii to thrips control.
The good results of the application of A. swirskii using blowers has stimulated the use of the predatory mite in roses.