Loss of appetite, discoloration, drying out, and shrinkage – the nematodes are doing their job
The nematodes in Entonem (Steinernema feltiae) and Capsanem (Steinernema carpocapsae) penetrate into insect larvae, such as caterpillars. You will then see them quickly stop feeding, discolor and shrink, which is a good indicator that the treatment has been effective! The level of damage to your crop is also a good indicator of whether or not the nematodes are proving effective.
When a nematode attacks a caterpillar or larva, a dramatic scene will ensue; the host is eaten from the inside out. The bacteria start by liquefying the innards, and then the nematodes slurp up the contents. At the end all that is left is the shell, which is why you will see the caterpillar or larva turn yellowish brown to brown over time, and shrink. Caterpillars are usually juicy, and sometimes a little sticky, but when attacked they become dry. If looked at through a microscope, you will see the small nematodes wriggling inside the caterpillar. Infected larvae in a humid environment can quickly become slimy. After that, you will not see them again.
A combined approach to thrips
In addition to the effect on the pests, you should also see the damage to the crop decrease. If treatment with nematodes is successful, you will see less damage. With thrips too, the crop damage should reduce considerably. By counting the sticky traps or rinsing the plants, you can also check whether numbers are in decline.
Thrips always need a combined approach. In the early stages of cultivation, predatory mites such as Swirski-Mite (Amblyseius swirskii) tackle the initial larval stages. However, if large numbers of insects fly into the greenhouse, you will need some extra help, which is where the nematodes come in. Doing this will help you to break the cycle when the level of infestation is high. Green plant protection products can also be used.