Thrips are dangerous pests of vegetable crops
Authors: Klechkovskiy Y. , Glushkova S. , Palagina O. 
Published: September 2019

Goal. To provide information about dangerous pests of vegetable crops — thrips. To describe the morphology and biology of the pest, the methods of spreading and harmfulness, provide information on the necessary phytosanitary measures to restrict its development and reduce the harmfulness, and to justify the need to use alternative biological methods to control the population of thrips in the conditions of the Southern steppe of Ukraine on an example of the most common of them — tobacco thrips (Thrips tabaci Lind.).

Methods. Informational and analytical. The collection of information was carried out in accessible specialized literature and the Internet.

Results. The information about sucking pests of vegetable crops - thrips is given.  Thrips are known for a long time, they belong to wide polyphages, that is they harm a wide range of cultural and wild plants  (from 100 to 400 spesies). On an example of the most common of them — tobacco thrips (Thrips tabaci Lind.) there is given information about the morphology and biology of the pest, the methods of its spreading and harmfulness, as well as the information on the necessary phytosanitary measures for restriction its development and reduction of the harm. This most widespread and dangerous polyphage, due to its close connection with plants, where its entire life cycle develops - from eggs to imago, has inhabited almost all greenhouses. In the natural conditions of the southern region of Ukraine, the tobacco thrips were found on large areas of vegetable crops with the seedling method of their cultivation, mainly cucumbers, tomatoes, onions, cabbage, watermelons, and the like. It harms bulbs in vegetable stores, which leads to a deterioration in the quality of garden plants and gardening material. The reaction of the plant to the damage by the trips is desensitization, which is manifested in growth retardation, distortion and loss of turgor of damaged leaves, which later become yellow and dries. Imago winter, mostly females, in greenhouses - in different slits, and in open ground - in the upper layer of soil at a depth of 7-10 cm, under plant remains or in the rootstock of perennials or weeds. At temperatures below 0 ° С and in the absence of snow cover, insects die. The pest spreads at all stages of development - eggs, larvae, imago - with planting material of vegetable crops (with plants or in soil), transport, containers, workers' tools, their clothes or footwear. This also occurs when collecting, packing and selling contaminated products. This is especially true for cabbage, with which the thrips can get to the greenhouse or indoor plants. In the conditions of the steppe and forest-steppe zones of Ukraine, the tobacco thrips can develop in open soil at temperatures over 10 ° C during the growing season from the second decade of May to the end of September, causing significant damage to vegetable crops. If this is the case, the pest can give 3-4 to 5-6 generations, depending on the weather conditions. In the population control of tobacco thrips, satisfactory results are received by systematic cultivation of plants with the following insecticides: Akketlik, Aktar, Phyitoverm, Karate Zeon, Confidor Maxi (with irrigation water) and others. It is obligatory to change preparations during the growing season. On the onion fields thrips is successfully reduced with insecticide of natural origin Spintor when using periodic spraying of plants. Because thrips are very resistant pests, therefore, in addition to insecticides, the use of predatory mites Amblyseius cucumeris, A. barken, A. derenerans, as well as predators of Orius laevigatus, O. magusaculus can be used to destroy them. Taking into account that nowadays the protection of vegetable crops takes the direction for the use of biological agents against pests - polyphages, special attention should be paid to the use of natural enemies of the tobacco thrips.

Conclusions. In the natural conditions of the southern region of Ukraine, tobacco thrips were found on large areas of vegetable crops, therefore, there are all reasons for phytosanitary surveys of open-air vegetable crops to detect and eliminate this dangerous pest. Taking into account that nowadays the protection of vegetable crops takes the direction for the use of biological agents against pests - polyphages, special attention should be paid to the use of natural enemies of the tobacco thrips.