FARMS:WHAT ARE THE THRIPS
When we have a crop, we must know everything that can affect it, learn to recognize it and diagnose it, in addition to home-made medicines because fertilizers and treatments are often expensive.
Today, Tuesday we will know the thrips, what are they?
The thrips (Frankliniella spp.)
Its distribution is cosmopolitan. They are present practically in all the ecosystems of the world, affecting a great variety of crops. They belong to the order Thysanoptera, with a very high variability between the different species.
Some 5,000 species of thrips have been cataloged, with sizes ranging between 0.3 and 2mm. This characteristic makes its identification extremely difficult, and is the main reason for its successful dispersion throughout the world.
Thrips are tiny, thin insects with hair on the edge of their wings.
-They measure less than 1.5 mm and their color varies, depending on the species and the stage of life.
-Thrips are born from eggs and go through two immature stages (nymphs) in which they feed and two in which they do not feed (prepupa and pupa), to then reach the adult stage.
-Some thrips are beneficial predators of other insects and mites.
-Most pest thrips feed in hiding, often on buttons and at the tips of shoots or under the sepals; the damage they cause is usually noticeable before the thrips are visible.
-Greenhouse thrips and western flower thrips are two of the most common pest species in gardens.
Thrips development.
Thrips can complete their cycle (one generation) in less than a week. The high temperatures and the lack of environmental humidity favor the development of this plague. The pest decreases as rainfall occurs.
The life cycle of the thrips in the plant begins with the oviposition in the leaf, then the nymphs emerge and feed by scraping and sucking the leaves, which causes their dehydration.
There are several types of thrips that attack different varieties of plants. The adults place the eggs in the leaves and the larvae emerge to feed on the plant, being their main objective the buds and the branches about to emerge. The larvae are similar to adults, but without wings and their color changes from white to yellow-brown as they grow. The chrysalis often falls to the ground where it remains until the adult emerges, so the earth can also be a source of infection.
Symptoms and damage caused by thrips.
We can realize the presence of thrips in our crop if we observe a scraped and burnt type of the leaves and an opaque green color in our plant. DSCN2646
It can cause growth retardation during the early stages, coiling of the head that can cause the death of the plant, damage to the leaves, presence of diseases (because the thrips is a transmitter of diseases), low yields, loss of plants.
Your eating habits are very varied. There are species that feed on leaves and flowers, however, many are fungivores-feeding on spores or fungal hyphae. In addition, some other species are predators, and feed on other arthropods, such as mites and even other thrips, sucking the hemolymph of these.
Most thrips live on dead plants feeding on fungi. Although they depend on plants, in reality, less than 50% of the species feed on them, or cause them some kind of damage. So, how do they depend on them? - They need them to complete their biological cycle.
As they have a perforator-sucker buccal apparatus, the insects feed by sucking the contents of the cells, producing gray spots. This causes cell death and severe damage to leaves and flowers. Sometimes, the damages are so severe that they cause the leaves to fall and in other cases, the plants form galls in response to thrips.
Although physical damage is important, the main problem with these insects is that many species are carriers and transmitters of plant viruses - of the tospovirus group.
There are currently more than 20 types of viruses considered plague due to their harmful effect on different cultivated plants. One of the most important in tomato tanning virus, transmitted by the species Frankliniella occidentalis -present in Spain- that causes huge losses in tomato crops worldwide.
Something interesting is that only the insects that acquire the virus in its larval phase will be able to transmit it. Why? -In adults, viral particles degrade at the level of the intestine and do not pass to the salivary glands that is where they are transmitted.
Thus, we can deduce that an adult trips virus transmitter, has contracted in its instar larva. How important is this information? -Thanks to this, we understand that to make an effective control of the viruses transmitted by these small pests, we must control it in larval phase or before.
How Trips control is achieved.
The best insect control is achieved with a combination of several methods - what is known as integrated pest management - that include cultural, etiological and pesticide use measures. In the case of thrips, an excellent cultural measure is to eliminate all the weeds that can serve as hosts for insects.
If we want to be efficient, and control populations before they are very large, we must attack early. For this, we have traps catch insects. This product contains an attractive bait, combined with yellow coloring that is irresistible. We have to place them as soon as possible, at a rate of 1 trap per plot of 20 m2. If the population is already very large, the proportion should be doubled or more.
We also have insecticide action products, which are ecological and do not harm the environment. For example, we have the neem insecticide that acts by contact and interrupts the molting process in the larvae. In addition, it serves as a repellent and inhibits the feeding of insects. Additionally, it does not cause harm to humans and has very low toxicity for beneficial insects and the surrounding fauna, thanks to its ecological character.
Another similar product that you can find in our selection is the quassia amara insecticide. This liquid acts as a repellent and exerts an insecticidal effect by contact and ingestion. It produces a very bitter taste in plants, which inhibits the feeding of insects. In addition, it is safe for pollinating agents and entomopathogenic insects.
Very small animals but that can become a huge problem.