Thrips – All you need to know about this pest

Thrips are insects that belong to the order Thysanoptera. They are usually black or brown, measuring between 1 and 3 mm, with a cylindrical and elongated body. Many of them are pests of cultivated plants, causing discoloration in flowers, leaves and fruits.

Thrips - All you need to know

The damage is caused by the laying of eggs on the plant. The appearance of silver spots on the leaves is due to the fact that when feeding on them, the plant reacts to their saliva. In the case of the fruits, it is the nymphs that feed on them.

These insects can also be vectors for more than 20 viruses. Among them is tomato wilt virus, which is one of the most damaging pests. The species Frankliniella occidentalis, a cosmopolitan thrips, is the main vector of this disease.

A couple of weeks ago I found several of my hibiscus plants attacked by thrips, which is why I have decided to write this article, in order to help you combat this little insect in the same way that I did in my garden. In any case, we will not start with the methods of prevention and elimination of thrips, we will first get to know our enemy better before fighting it. 😉

1. Identification of thrips

Thrips are difficult to see with the naked eye, adults are on average 0.5-1.5 mm long. Their bodies vary from pale yellow to brown and they have thin wings fringed with fine setae (setae). Even the smallest juveniles can be seen in the field with a magnifying glass. The larvae resemble the adult stages in almost all respects, except for the presence of wings. Wing buds are sometimes visible during the prepupal stage.

2. What is its life cycle?

Variations in the length of each instar occur between species of thrips, but in general:

  1. The females lay eggs directly on the tissue. of the host plant.
  2. The larvae emerge and begin to feed on the plant.
  3. After two molts, the larva enters the prepupal stage (lasts about 1 day) during which the wing buds develop externally.
  4. The immobile pupa gradually forms with antennae. folded on his back (develops on the ground or in leaves curved and rarely seen).
  5. Adults emerge from the pupa after 2-3 days.

3. Natural enemies

Predatory mites and bugs, larvae and adults of lacewings and ladybugs are some of its natural enemies. Predatory thrips are under investigation. Other biological control agents include pathogenic fungi and parasitic nematodes.

4. What areas are they in?

From temperate zones to the tropics. Thrips have more than 100 host species, including economically important Florida crops such as strawberries, tomatoes, peppers, cucurbits, cotton, and ornamentals.

5. What damage do they cause?

Among the most common damages that we can mention are the following:

  • Pepper thrips, flower thrips and western flower thrips are known to cause significant damage to leaves, flower buds and fruit.
  • They are vectors of different viruses such as tomato wilt virus (TSWV), peanut ringspot virus (GRSV), pepper leaf curl virus (CLCV), peanut necrosis virus ( PNV), tobacco streak virus (TSV) and watermelon silver mottle virus (WsMoV).
  • Common symptoms include misshapen leaves and fruit, whitening and discoloration of leaves and flowers, necrotic tissue, defoliation, and general stunting.

6. How to prevent a thrips attack

Prevention against a pest is based on doing things right: adequate irrigation for the plant and the climate, slow-release solid organic fertilizer, respecting the recommended planting schedules, correctly orienting our orchard to obtain the necessary hours of sunlight and, above all, maximizing biodiversity, planting as many plants as possible and taking care of the compatibility between them, which will greatly strengthen the resistance of our garden to all kinds of pests and diseases, also enabling the life of a greater variety of beneficial insects .

Surveillance is also important, the more assiduously we observe the state of health of our plants, we look at the underside of the leaves and their vigor; the lower the risk of suffering from an infestation and the more effective manual elimination will be.

Remember that the objective is not to “eliminate” thrips, but to prevent our garden from suffering too much damage without having to fill it with insecticides or aggressive chemicals. A little growth does not hurt and will maintain populations of ladybugs and lacewings that will regulate their population.

7. How to treat a thrips infestation

If prevention methods fail and thrips populations are in danger of getting out of control, we probably have to resort to an ecological phytosanitary product that helps the plant fight the parasite, stop and eliminate the plague.

The ideal would be to remove the trip manually, since it is the most innocuous technique, we can do it if the trip we have is little and our patience is great, but it is complicated since it is a very small insect and its thorough elimination seems practically impossible. no matter how small the scale of our orchard is unless our monitoring is very precise almost on a daily basis.

One of the most effective products in the fight against thrips is potassium soap, it has the property of softening the exoskeleton of insects, they are very weakened and end up dying, it is also a natural and harmless product for health.

After using potassium soap, approximately one hour later, it is very good to apply neem oil, it is a natural insecticide that is extracted from the fruit of this tree, which acts against a wide range of pests such as: whitefly, leafminer, red spider , thrips, aphids, louse, potato beetle, bed bugs… The joint action of potassium soap and neem makes the treatment even more effective.

Next, a cleaning product should also be applied to remove the molasses, an extraordinarily effective attractant of fungi and bacteria that are harmful to the plant. These products also often contain disinfectants that will protect the plant and kill fungus and bacteria.

Another equally valid option is the use of prepared, totally organic products that prevent and combat most pests that can attack us, such as those that use the homeostasis technique, which dilutes an insecticide to infinity, leaving a single trace. of it totally innocuous but effective in the fight against insects. There are also products based solely on protective plant essences.

More information:

Comments are closed