Who is thrips
If light yellow angular spots form on the leaves, and then they turn into silver-yellow stripes with black dots, know that the plants will soon dry out, because thrips have taken over them. It’s time to start the fight, as you need to get rid of thrips as quickly as possible.
Amateur gardeners cause great damage to cucumbers, tomatoes and peppers by pre-growing onions for feathers, green crops and even flowers and ornamental plants in greenhouses in early spring. The fact is that such use of greenhouses leads to the reproduction of a dangerous pest – tobacco thrips. This insect is almost omnivorous and it is not easy to fight it: it lives on more than 100 plant species from 47 families. These pests can almost always be found in the scales of onions and garlic. Thrips causes damage to the crop of potatoes, peppers, tomatoes, tobacco and gourds. This pest affects not only leaves, but flowers and fruits. Especially fond of thrips gladiolus.
Thrips flower is also harmful because it is a carrier of cucumber mosaic virus and tobacco mosaic virus, which are very dangerous for plants, against which there are still no effective control measures, except for preventive ones. Sick plants are destroyed.
These pests are still unfamiliar to summer residents and therefore become noticeable only after its mass reproduction occurs and crop losses are inevitable. In an adult thrips, the body is thin, narrow, yellow, 0.8-0.9 mmlength. The wings are narrow, yellowish or grayish-yellow, fringed at the edges. Larvae in body shape resemble adult insects, but without wings and smaller; at first they are whitish, later – light greenish-yellow. Thrips overwinter in plant debris, under dry onion scales, and also in the soil at a depth of 5-7 cm. In early spring, in late February – early March, they live on weeds and then on cultivated plants, penetrating into greenhouses.
Winged thrips rise to the surface through cracks in the soil and lay their eggs directly under the skin of the underside of the leaf.
For the development of flower thrips, the most favorable temperature is 25-30°C. Thrips in a greenhouse in one season gives 6-8 generations. The average lifespan of a female feeding on plant sap is 20 to 25 days, during which she lays up to 100 eggs. After 3-8 days, larvae hatch from them, which first feed on the juices of plants, and then go into the soil. You can fight it, but there are a number of the simplest preventive measures to protect plants in film greenhouses from thrips.
Prevention is the key to plant health
1. Greenhouses intended for growing cucumbers and tomatoes should not be used for early spring planting of onions, green crops and ornamental plants.
2. Before planting onions in the area, it is necessary to disinfect the bulbs;
a) in hot water (45°C) for 10 minutes, followed by cooling in cold water;
b) soak the bulbs (gladiolus and other bulbous plants) in a 2% solution of sodium nitrate for 24 hours;
c) dry the bulbs for 5-7 days at a temperature of 35-37°C;
d) look at the bulbs intended for sowing for the presence of small moving insects (thrips), which can be quite easy to notice even with the naked eye.
3. Do not treat plants in the greenhouse against aphids with tobacco dust and infusions of tobacco, onion scales or garlic. Only decoctions of them are needed.
4. Timely destroy plant residues in the greenhouse; carry out autumn digging of the soil; destroy weeds.
This should be done around the greenhouse.
Dealing with thrips
If there was no prevention, and the number of thrips has reached a harmful level, it can be controlled with BOVERIN at a concentration of 0.5-1%.
If thrips appeared on the plants, how to get rid of them is not a difficult question. Double treatment of plants populated with thrips with an aqueous suspension of bowerin at intervals of 10-12 days destroys the pest.
To exclude the transmission of a very dangerous plant disease by thrips, it is necessary to regularly, from June to September, once every 10 days, inspect cucumber plants for damage by the cucumber mosaic virus and destroy diseased plants without any pity. In plants affected by the cucumber mosaic virus, light greenish vague spots appear on the leaves, mainly between the veins, the internode and petioles are shortened, plant growth slows down, the number of flowers and especially fruits decreases, the fruits acquire a variegated mosaic color. The virus is not transmitted by seeds. You can’t get a crop from diseased plants, and you can’t cure them, and the risk of infection spreading to other plants is very high, especially if there are aphids and insidious thrips in the greenhouse.