Thrips: small pests

Thrips are small insects of the order Thysanoptera, which can cause serious damage to agriculture. There are several varieties of thrips, one of them is called “garden thrips”, and already the name makes us understand that it can be counted among the insect enemies of the garden. In addition to many garden plants, there are also insects on the trees in the orchard.

The damage caused by these pests is caused by the bites with which the insect sucks sap from plant tissues, usually in the leaves. This causes small spots on the leaves that make the attack recognizable. Collateral damage is that thrips bites are often a vector for viral diseases. Like the whitefly, the thrips also lives very well in greenhouses, thanks to the more constant temperature, and is therefore a particular problem for protected crops.

The fight against this insect in organic farming can be done in several ways: with chromotropic traps, looking for antagonistic organisms or with authorized insecticides, because of natural origin. The important thing is to know how to recognize the infestation and to intervene in time, before the insects proliferate and the plants are seriously damaged.

Contents [Ocultar]

• Characteristics, recognition and damage

  • Harmful Thixanoptera Species

  • Damage caused by thrips

• fight against thrips

  • Use of vegetable macerates

  • Organic thrips insecticides

  • organic wrestling

Characteristics, recognition and damage

Thrips are insects that are difficult to recognize with the naked eye because they are very small. , usually a millimeter long or even less. They have a body of varying colors, they are usually disengage , between white and green, but become more brown in the autumn generations. Looking closely, we notice the conical body, which ends in the stinger, and the wings.

Although they are small, they can be seen with the naked eye and their light color makes them clearly visible in the green of the plants, however they generally take refuge under leaves or in flower buds and for this reason it is not easy to find them. To identify them, you can use chromotropic traps these small insects are particularly attracted to color blue .

Thrips live with temperatures between 12 and 30 degrees , around 25°C has its optimum climate. For this reason it can generally be found in the field from April to the end of September, but under the tunnels it can be present almost all year round.

Harmful Thixanoptera Species

Among the different species, we first recall the orchard thrips ( triphs tabaci ) which is the most widespread in our regions and the one that causes the most damage to horticultural plants. We include it among the worst insects that affect onions than those that affect tomatoes. Other horticultural plants commonly harassed are melons, potatoes, and various cruciferous plants (i.e. cabbage).

Another common parasite is frankliniella occidentalis also called western greenhouse thrips . We imported this insect from North America and today it is a big problem for protected crops, especially tomatoes.

The most common thrips in the orchard are citrus thrips ( Heliothrips haemorrhoidalis ), the nectarine thrips ( Taeniothrips meridionalis ) and the grapevine thrips ( Drepanothrips reuteri ). The names are already indicative to understand which crops are most harassed by each insect.

thrips damage

Thysanoptera damage plants with their darts . On the leaves, the damage is easily recognizable by leaf spots. which go to the sheet. When the insect stings the flowers and buds, on the other hand, there is a risk of leaves, which can seriously damage the crop. In the fruit, the sting causes notches no different from those caused by insects, but if the sting occurs in a fruit that is still small, it can also cause deformation .

In addition to biting thrips They also lay their eggs in plant tissues. doubling the damage.

The problem caused by lymph aspiration is compounded by the fact that thrips are often a virus transmission vehicle : the passage from one plant to another transmits diseases.

fight against thrips

The fight against thrips can be carried out in different ways, from the point of view of natural cultivation, let’s first talk about the most easily applied and non-toxic methods, that is, plant preparations, and then see with which biological insecticides we can counter the threat. Finally, there are forms of biological control, interesting for those who cultivate professionally, but not within the reach of those who have a family garden.

Use of vegetable macerates

There are several vegetable macerates that can be useful in the organic garden, these are preparations that can be self-produced and therefore are free They also have no negative impact on the environment. To fight against triffids in particular, some of these macerates can be useful.

• Macerated nettle. It is the most “aggressive” of the preparations, a real insecticide which can be used to kill insects and which requires some precautions in its use.

• Garlic maceration or decoction. Against garden thrips and other thrips, garlic has a repellent function.

• Chilli marinade. Even hot pepper, thanks to capsaicin, is not welcomed by these small insects, so it can be used to defend the garden without chemicals.
• Absinthe macerate or decoction . Periodic treatments with wormwood maceration can serve to prevent the presence of thrips in our garden plants.

• Marinated or cooked. Tansy has properties similar to wormwood and is a good repellent against thrips.

Bio insecticides against thrips

When the going gets tough, we can choose to use an insecticidal product , but with great attention to the days of scarcity and without even touching useful insects (bees, bumblebees, ladybirds, etc.). Always read the instructions and precautions of the product container.

Keep in mind that the insecticides authorized in organic farming all act by contact , so they must physically reach the insect to kill it. As thrips tend to hide in the shoots and under the leaves, it is necessary to spray every part of the plant well and repeat treatment after 5/7 days to eliminate individuals that escaped from the first pass.

The recommended insecticides against thrips are:

• Neem oil or azadirachtin. I prefer pyrethrum because it is less toxic.

• Pyrethrum. An insecticide which, although authorized in organic, has its own toxicity, to be used with great care.

• Sweet orange essential oil. Natural active which acts by contact, less effective than the two other methods but respectful of the environment.

biological combat

There are entomopathogenic insects capable of killing thrips, so it can be done in professional organic farming. biological control release individuals of these species and let them parasitic prey . This method works particularly well in protected crops, as it is a more closed environment where beneficial insects remain more confined.

In the greenhouse against garden thrips are used especially Rincoti Antocoridi (orius) although several other natural parasites have been tried

.