Predatory Mite of Whitefly and Thrips
Amblyseius (Typhlodromips) swirskii is a polyphagous predatory mite, meaning that it feeds on several preys. For a fast growth of its population, A. swirskii needs a satisfactory food source and prefers whitefly and thrips. A. swirskii also feeds on pollen and in a certain degree on spider mites and tarsonemid mites. This gluttonous predator can be used in sweet pepper, cucumber, eggplant, strawberry and some ornamental crops.
The whitefly’s larvae feed on plant juice and the surplus on sugar will be excreted as sticky honeydew. The honeydew improves the growth of moulds and this interferes in the photosynthesis and transpiration of the plant. Furthermore, whiteflies are true vectors of many viruses such as TYLCV. It is especially the eggs in the primary larval stage of greenhouse whitefly as well as tobacco whitefly that A. swirskii feeds on. It can consume about 10 eggs and young larvae a day.
Thrips cause damages in many different ways in the crop. Plant cells emptied of their content by the feeding of thrips take a grey or silver colour. Also, thrips excrements can lower the value of ornamental crops. Eggs are laid in the leaf tissue and can be recognized as warty suberizations. Depending on the type of crop, deformations and discolorations of the leaf, fruit and flowers are detected. Thrips are also known vectors of many viruses. A. swirskii mainly eats the young thrips larvae. The predator capacity can be compared with that of A. cucumeris which means that about 5 larvae are consumed a day.