Category: News
Date published: May 13, 2020

Keep a close eye on thrips

Western Flower Thrips Frankliniella occidentalis on a leaf Western Flower Thrips Frankliniella occidentalis on a leaf

Thrips can cause major damage - that's nothing new. This does mean that you need to detect thrips in good time. Sticky traps are a useful tool in monitoring the development of infestations. Regular scouting in the crop is also essential as it allows you to trace the larvae. This increases the chance of successful pest control.

The yellow Horiver sticky traps can be found in almost every greenhouse, and for good reason: they are a proven means of monitoring the development of infestations. They are an essential element in Integrated Pest Management. The development of thrips populations can also be monitored very well with the aid of sticky traps. If the number of thrips caught is increasing, it's time for extra action!

Sticky traps lure adult thrips

Keep in mind that by the time the first thrips appear on the sticky traps, the infestation will have been developing for quite some time already. At high temperatures, a week and a half passes between the hatching of an egg and the adult insect flying around. At low temperatures, however, this takes more than a month. The thrips larvae never appear on the sticky traps simply because they cannot fly. In short: by the time you see thrips on the sticky trap, the thrips problem has already reached a fairly advanced stage!

Search in the right places

It's therefore important to spot the thrips infestation as early as possible, and to detect the larvae too. After all, the sooner you can identify the thrips problem, the better the chance of success in eliminating it. Detecting the larvae requires practice. Considering how small the larvae are, a magnifying glass is an indispensable tool. It also helps if you know where to find the larvae. In some crops, you will find them mainly in the heads of the plants, while in others they tend to be in the flowers or on the leaves. Some types of thrips prefer the lower parts of the crop. Contact your Koppert consultant for crop-specific advice. Not only the detection of larvae is reason for a 'thrips alarm'; you also need to be alert to deformities, damaged spots, silvery spots, and excrement in the crop.

Time to sound the alarm? Or not...

How many adult thrips or larvae you can tolerate in your crop depends on the type of crop. For example, if you find three thrips on the sticky trap per week, this may not indicate a problem in one crop but could be a reason to sound the alarm in another.