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Western or California flower thrips is a very dangerous pest that is distributed over a large territory of Russia, from the western border to the Siberian and Caucasian regions.
It is dangerous not only because it is almost omnivorous and destroys flower and ornamental plants, fruit-bearing trees, vegetable plantings, but also can act as a carrier of many dangerous diseases.
At this stage, California thrips have been seen on over 250 plants.
Description of the pest
California thrips is on the list of pests most often dealt with by employees of the Plant Quarantine and Phytosanitary Monitoring Department. Its larvae are often found in food shipments and flowers for sale.
The birthplace of the western flower thrips is considered North and Central Americawhere it is widespread throughout the continent from mexico and to Alaska... It was first identified in California, thanks to which it acquired its name. However, they assume that it was originally brought with flower products from one of the countries of South America.
In European countries this pest was for the first time recorded in 1983, and has since spread throughout the European part. In Russia he was seen in the early 90s of the 20th centurywhen it was brought along with the flowers.
An adult has a length 1.4-2.0mm... The body is narrow, the color may vary from light yellow, to dark brown... The head is yellow. The wings are fringed, slightly darkened. The larvae are similar in appearance to the adults, however, they are much smaller in size and with a lighter color.
REFERENCE! The main differences between the Californian thrips and other species of thrips are the different color of some parts of the body and a different structure (different structure of antennae and bristles, different lengths). Due to its small size, species identification can be performed under laboratory conditions under a microscope.
California thrips spend winter warm inside the greenhouse - adults take cover with plant debris, larvae - in the ground. In warm areas, overwintering can take place in open soil. In the spring, after the seedlings are planted, insects attack it.
Females place eggs at the top of the stem and create holes in the leaves. For a month, eating a plant, thrips can postpone up to 300 eggs... This amount can be increased if the insect feeds on pollen.
The hatched larvae transfer two stages of development on the plant, eating it, and then pass into the soil. In total, it takes 15-21 days to fully develop one colony of California thrips. Under ideal conditions, in one year, 12 to 15 generations.
Photo of the Western California flower thrips:
What plants does it eat?
Western flower thrips is a widespread pest. It amazes cotton, bow, cucumber, pepper, tomato, strawberries, peach, grapes and other types of fruit and vegetable plants... In addition, flowers are also attacked: roses, cyclamens, chrysanthemums, gerberas etc.
REFERENCE! Insects in primary and adult forms extract sap from plant crops.
What is the danger of a pest for plants
In the early stages yellow spots are formed, roughness. With the passage of time, these spots are joined together. After the withering away of the damaged shoots, they fall off.
During a mass infection with California thrips, the destroyed areas are clearly visible, there is a curvature of the stems of infected plants, a delay and deformation of the growth of young shoots.
Flower buds nutrition leads to disruption and twisting of flowers... Buds damaged by California thrips do not open and dry out. Eating pollen prevents the plant from forming full flowers.
IMPORTANT! Infection with a pest leads to a significant decrease in yield, a drop in the market value of plants grown for the purpose of selling (for example, decorative flowers), and a large colony of insects can cause the death of the entire plant.
In fruit crops, characteristic damage is also observed. So, silver stripes appear on sweet pepper, strawberries change color, the shape of the cucumbers changes and the vegetables are deformed, holes appear on the surface of tomatoes.
In addition to destroying shoots, the pest is a carrier of viral diseasesthat many plant species are exposed to. The most common is spotted wilting of tomatoes.
The main symptoms of infection are - the appearance of bright yellow spots on foliage, stem fragments take on a dark shade. To transmit infection, thrips need to feed on the plant for 30 minutes.
Features of pest control
Destruction with chemicals is difficult due to a number of factors. At first, it is a very small and secretive insect, and usually hides in buds, buds, flowers, under various kinds of scales. This makes it difficult to provide direct exposure to chemicals.
SecondlyIn America, where it comes from, the California thrips has gained immunity to a large number of insecticides. In greenhouses where this insect is most active, chemicals against it are not compatible with other insect repellents.
Currently, the destruction of flower thrips can be done in various ways:
- Mechanical - Plants that may experience a pest infestation should be covered with a fine mesh with small cells. She is blocked by window and doorways;
- Agrotechnical - visual control and quick elimination of infected shoots, careful removal of weeds and plant residues. In the greenhouses, special traps for insects are hung up, which can prevent colonization with thrips or, using the analysis of collected insects, determine the degree of infestation;
- Biological - the fight against California thrips is carried out by releasing special species of ticks and bedbugs in an infected greenhouse. They are able to greatly reduce the size of the colony, however, it is impossible to completely destroy the pest in this way. In addition, it must be borne in mind that predatory insects attack only larvae and do not feed on adults;
- Chemical - several insecticides have been developed that can effectively combat the pest. Basically, these are highly toxic agents that need to be used with 3-5 day intervals 2-3 times.
California thrips (western floral) - a very small pest that affects a wide range of vegetables and fruit trees, ornamental flowers. In addition to destroying the plant itself, this insect can transmit a number of dangerous viral infections. The fight against him is complicated by the fact that thrips often hides in buds, flowers, under scales.
In conclusion, we bring to your attention a video about the invasion of the California flower thrips: