Hang up 25 Horiver sticky traps per hectare as soon as cultivation begins in order to measure thrips and whitefly damage. Counting sticky traps each week provides important information in good time regarding the correct quantities of natural enemies to deploy. Hang up slow-release bags of Amblyseius swirskii (3,000/hectare) as soon as flowering is sufficiently advanced. This can be done after at least two weeks have passed since the last treatment with abamectin. The bags produce predatory mites for four to six weeks, thus cushioning the negative effects of chemical residues. The mites can therefore be released sooner than when using shaker cans. If flowering temporarily ceases, (resulting in less pollen), the bags will continue to produce enough predatory mites to cushion the impact of these less favourable conditions. When Amblyseius swirskii is deployed, the predatory mites A. cucumeris and A. degenerans are omitted.

 

Once the first thrips appears in the crop or on a sticky trap, or at least six weeks after the last spray application of abamectin, Orius laevigatus should be deployed as a preventative measure. In the event of an increase in the numbers of thrips and still insufficient numbers of Orius in the crop, extra predatory bugs should be added.

 

Whitefly can be well observed on yellow sticky traps. The preventative whole-field introduction used in the case of thrips is also effective in combating whitefly. This is because a well-established population of Amblyseius swirskii suppresses whitefly. From February onwards, it is also advisable to introduce Macrolophus caliginosus as a preventative measure: 2 x 0.25/m² with an interval of two weeks, and to release parasitic wasps on a weekly basis, also preventively. In the case of damage by cotton whitefly, use Eretmocerus mundus, and in the case of glasshouse whitefly use a mixed product with Encarsia formosa and Eretmocerus eremicus. In the case of a mixed whitefly population, use both products!

 The combination of the predatory mite A. swirskii, which predominantly targets the eggs and crawlers (first larva phase) of the whitefly, and the parasitic wasps, which concentrate on the second, third and fourth larva phases of the whitefly, is effective because the two elements fully complement each other. If the first whitefly is not detected until later in the year, and there is an adequate population of A. swirskii, you should first consult your adviser regarding the action to be taken.