Tobacco trips (Thrips tabaci)
Tobacco thrips is a dangerous representative of the genus Thrips. The insect is common on all continents except Antarctica. Causes great damage to tobacco crops and vegetable seedlings. It is also known as Onion thrips, for its love of the vegetable of the same name. But despite the preferences in the feed base in the form of onions and tobacco, it is a polyphagous and feeds on more than 100 plants, among which Solanales plants are in priority. This pest comes from North America, like most of the insect pests brought to our region, it is an American. But he was quite able to adapt to the more severe climatic conditions of the CIS countries.
Description
Tobacco (Onion) thrips (Thrips tabaci) is a very small insect, about 0.1 cm long, with 2 pairs of fringed wings characteristic of its order. Sexual dimorphism of individuals is insignificant and is characterized by a lighter shade of males. The oral apparatus of thrips is of a piercing-sucking type, which characterizes the specifics of their nutrition. The insect pierces the surface of the plant and eats its juices, thereby weakening it and causing other negative consequences resulting from this, which we will discuss further.
Stages of development
The life span of the adult female tobacco thrips is 3-4 weeks, but in this short period of time they manage to lay about 100 eggs. Oviposition occurs on the plant, in its most nutritious areas for the insect — foliage, flower petals and tender parts of the stem. After the egg, the life cycle of the pest has 5 more stages — 2 stages of larva, pronymph, nymph (pupa), imago (adult).
Larvae are born 4-6 days after oviposition. After hatching, they immediately begin to feed on the plant until the pupation stage. Outwardly similar to adults, but wingless and smaller. During the initial stages of development, insects are on the plant and are exposed to the action of drugs. At the moment of pupation, they hide in the ground, thereby protecting themselves from external factors, and turn into adults. After turning into an imago, they return to the plant again and continue to feed on it.
The damage caused
As already described above, tobacco thrips has an oral apparatus of a piercing-sucking type. Sucking the juices from the plant, they destroy the natural structure and lead to the appearance of necrosis, that is, the death of tissues. Light stripes or even spots form on the leaves, and you can also detect thrips excrement in the form of black dots on the surface. In the process of feeding thrips, the leaves lose their chlorophyll, which leads to disruption of the processes of photosynthesis and transpiration (moisture exchange). Thrips are also carriers of viral diseases, which can seriously complicate the consequences for plants. In addition to the fact that the seedling is already weakened by the impact of the insect, it becomes extremely susceptible to dangerous fungal diseases and viruses, which it is not able to fight due to its weakness. As a result of these processes, the plant at best begins to slow down in development, and at worst it dies. Both options are unacceptable for us.
How to detect
Given the small size of tobacco thrips, it will not be possible to detect it just by glancing at the plant, alas. In addition to their small size, they lead a secretive existence and live on the back of the leaf, which complicates the process of searching for them. Therefore, it is necessary to carefully inspect the plant and its leaf, flowers, and stem for the presence of an insect. Pay attention to the black dots, which may be the consequences of the vital processes of onion thrips. Look at the integrity of the leaf, the appearance of light stripes or spots on it, an openwork grid. Inspect for puncture points on the plant. Sound the alarm if dried leaves, deformed flowers and stems have already been found.
Methods of struggle
Folk remedies can help with a small amount of tobacco thrips and will be effective in a flat. They include all kinds of decoctions and infusions, among which onion, yarrow, and tobacco are the leaders. But there are no statistics on these methods, so there are no guarantees either.
Chemicals have a significant number of insecticides that help to cope with the parasite. The advantage of this method is the prevalence of funds and the relative ease of use. The disadvantages should be attributed to the need for repeated use, which is associated with the life cycle of tobacco thrips. The drugs act only on individuals who are on the plant, and in the pupation stage, let me remind you, they are in the ground and resistant to insecticides. Also, the funds have to be combined and alternated in order not to cause addiction and the development of immunity in the pest.
Biological methods of protection, although they require certain knowledge, but at the same time they are the safest and most effective. Natural enemies of thrips control its population, eliminating the pest. Predatory mites are distinguished among the antagonists of tobacco thrips — Amblyseius swirskii, Amblyseius cucumeris, Phytoseiulus persimilis. As well as predatory bugs — Orius majusculus, Orius niger, Anthocoris nemoralis.
Do not lose sight of sticky traps, which have proven themselves very well in monitoring and destroying this species.