Let’s be honest. Thrips might only be 1.5 mm to 3 mm, slender, fringed-winged insects — but they’re also minuscule thieves who destroy hundreds and thousands of crops if they get their rasping-sucking mouth part on them.

With over  5,000 species of thrips roaming our land, entering the smallest flowers or tiniest cracks in stems and barks, we speak on behalf multiple growers across the globe when we say thrips are frustrating pests.  With that fact at the forefront of your mind, you can understand why it is so important to learn about them.

From thrips reproduction, to how they suck the life out of your crops, plus the art of using biological control to defeat them, below we’ve enlisted the essentials when it comes to knowing this natural plant predator.  After all, they do say, ‘keep your friends close, and your enemies closer’.

DAMAGE

What does thrips damage look like? From streaks to silvery speckling, and small white patches — these are all signs that thrips have fed off  your crops.

Thrips suck plant cells from many garden plants, flowers, fruits, and shade trees hence the marking that appears on your crop.  If you have a major infestation of thrips, your plants might be stunted with damaged flowers and fruit. However, it’s important to be aware that the damage  you notice might instead come from the virus that the thrips spread (usually tomato spotted wilt virus).

LIFE CYCLE

EGG:

Female adult western flower thrips are expected to lay around 2-10 eggs a day. They do this by inserting the eggs into soft plant tissue e.g. flowers, leaves, stems and fruit. However, if you are a sweet pepper grower, you should look for speckled patches on the crop’s leaves as this signifies that thrips eggs have hatched.

LARVAL & PREPUPAL:

Next is the larval stage, this part of the thrips cycle consists of 2 instars that feed and develop on leaves, flowers and fruit. Usually,  the prepupal and pupal stages complete their development on the ground or on the growing medium. Although,  some pupation can take place on the plant. It’s important to note that the pupa is at a non-feeding stage whilst it’s wings and other adult structures form.

ADULT:

Adult thrips have delicate, hair-fringed wings that allow them to move into and through crops. The life expectancy of a female adult thrip is 30 days. In temperatures near 20°C, the development from egg to adult takes approximately 19 days, if temperatures exceed 25°C, it takes 13 days.

BIOLOGICAL CONTROL

• Montyline: Amblyseius montdorensis is active at a broader range of temperatures than other predatory mites, making it perfect for controlling pests in challenging environmental conditions

• Amblyline: Amblyseius cucumeris is a predator of Western Flower thrips, Chili Thrips and several other thrips species
• Swirskiline: Amblyseius swirskii actively feeds on thrips larvae (larva stage 1 or L1).
• Hypoline offers some additional control as part of a programme with other control agents, but does not give adequate control if used alone.

• Oriline: the predatory bug Orius kill up to 80 adult thrips per day (while only feeding on a few).
• Thripline: To improve the control of Western Flower Thrip an “Advanced Monitoring” System” called Thripline has been developed by Bioline in collaboration with Keele University to improve timing of control measures by improved pest monitoring.
• Trapline t+: scientifically optimised with specific colours, patterns and thripline pheromone to mass trap thrips.