Plants damaged by thrips have light patches on the underside of their leaves, similar to those caused by red spider mites, but without the spider webs and with larger holes. The leaves later dry out and turn brown, and there are usually plenty of black droppings.
Flower thrips often live in the buds and cause massive deformations. The most common thrips species are Frankliniella occidentalis and Thrips tabaci.

Approximately 5,500 species are known worldwide, of which >230 live in Germany. Flower thrips are often brought to Germany with plant imports, which frequently cause major problems for horticulture.
Thrips are also commonly known as fringe-winged insects, thunderflies, thunderbugs, thunder animals, thunderworms or black flies. The animals are winged, although thrips rarely fly. Their biting apparatus (mandibles) enables them to suck and sting. Most animals are 1 mm in size, but some can grow up to 3 mm. The nymphs are smaller and whitish-transparent, while the adults are light-coloured with dark bands.

Thrips reproduce primarily through parthenogenesis, but sexual reproduction is also possible. The male can mount and fertilise the female, but unfertilised eggs always produce males. The ratio of females to males has rarely been studied, but is around 4:1. In most species, females only allow fertilisation once. The further development of the eggs is also highly variable.

Blue boards and weeding in the immediate vicinity are essential. Many chemical insecticides can be used, but treatment must be repeated every 3-7 days.

The use of predatory mites in a bag system is promising. In addition to bran as a carrier substance, the bags also contain storage mites (Tyrophagus sp.), which the predatory mites feed on. They should therefore be understood as breeding stations in which sufficient food is available, forming the basis for the ongoing reproduction of the predatory mites.

These treatment methods from centuries past clearly show that thrips have always been a nuisance. These articles are for informational and entertainment purposes only. Please note that the use of some of the chemicals mentioned here is no longer permitted today, as they can be extremely harmful to health (including that of the user) and very harmful to the environment. Reading, reflecting and smiling are permitted, but do not attempt to replicate these methods.