Thrips: What are they?
Thrips are parasites – or pests – of plants and are one of the most annoying and difficult problems to solve in indoor growing. Therefore, it is advisable to prevent possible infestations. In this article we will talk about how to prevent and eliminate thrips with natural methods (biological control) or traditional insecticides (chemical control).
But first let’s see what they are and how they behave.
Like many other types of parasites, they also attach themselves to the structure of the plant, in particular to the leaves, and suck out the sap. These small insects represent one of the biggest problems of all growers, especially those involved in greenhouse and indoor cultivation, also because they reproduce up to 12 times a year and – once they reach adulthood – begin to fly and can, therefore, pass quickly from one plant to another.
Among the plants most attacked by thrips we find those of hemp and cotton, but – in reality – they also find other types and varieties of plants attractive. Their ideal climate – to spread and reproduce – is the warm one, so it will be advisable to watch over the plants especially in the summer season.
How common is this parasite?
Thrips are not common unlike other pests, but – under certain greenhouse conditions – these small animals can be very aggressive.
Where are the thrips and when?
Thrips attack the leaves and are usually visible on top of the leaf. In winter, they hibernate and activate at temperatures above 16°C. In indoor cultivation, the artificial climate allows them to be active all year round. The eggs are first found under the leaves and then fall on the ground, and then hatch when temperatures are optimal (26°C to 28°C).
What do they look like?
Thrips are about 1.5 mm long and are visible to the naked eye. The adult specimens develop wings but rarely use them, in fact they prefer to walk on their legs and fly only in case of danger. They have a dark colour ranging from yellow to brown. The larvae are half the size of adults, lighter in colour and without wings.
What does it do to the plant? Thrips damage
The thrips cut the leaves – through a structure associated with a tool such as a saw – to drill and scrape the leaves until they reach the sap on which they feed. On the surface of the leaves they leave white or silvery patches, the leaf appears scarred and covered with white crusts. The thrips leave behind them black spots of excrement above and below the leaves. The damage caused by thrips initially resembles that of mites or leaf miners, but in more serious cases they cause the plant to lose its colour.
Thrips damage on tomatoes, vines, orchids, citrus fruits and peach trees
Thrips are parasites that attack numerous types of plants; among the most frequently damaged are tomato plants, vines, orchids, fruit trees, especially citrus and peach trees. The stings of these annoying animals suck the nutritive elements of the plants they attack and cause widespread depigmentation, which results in abnormal white spots on the leaves, thus causing a state of disease and suffering of the plant. This, in fact, facilitates the arrival and spread of infections due mainly to attacks of alternaria and botrytis, which mainly involve leaves and fruits.
Prevent the Tripids
As for all the other types of parasites, also for thrips is the same advice as always, which we have seen in other posts of this blog dedicated to the fight against the most feared parasites: to avoid their spread we need to be careful often and avoid that they colonize our plants. To do so, it is advisable to keep the cultivation environment clean, especially when growing indoors, remove dead leaves and disinfect environments and equipment for daily use, to avoid the proliferation of pests and insects, but also mold and other dangerous organisms.
To prevent an infestation of thrips, it is possible to use yellow and blue chromotropic traps, very similar – in mechanism and functioning – to fly paper, which first attracts flies and then traps them. In outdoor gardens you can also use garlic to keep them away. Another recommendation is to increase protection by using natural products such as – for example – Vebi Bio 3in1 which generates a natural barrier against insects and Neem Oil which feeds and protects plants in a natural way.
How to fight and eliminate thrips: natural remedies
To eliminate pests you can introduce natural enemies into the affected area, such as predatory mites. The most effective way to permanently eliminate thrips is to wash the plants with vegetable soap and then use a pyrethrum-based product.
Recommended traditional products to remove the infestation: insecticides and chemical control
If you prefer to use traditional chemicals (normal insecticides) to fight thrips and eliminate them from your plants, remember to always protect your eyes and hands, because they are potentially toxic substances.
Below we present a small selection of products, both natural and traditional, particularly recommended and effective to fight thrips.