Profile

The melon thrips originates from South Asia. It has now spread to many tropical countries. In Central Europe, it could only live in greenhouses, as it cannot survive cold winters. The melon thrips is a Union quarantine pest and is subject to legal regulations.

Biology

Thrips are usually only discovered late on infested plants due to their hidden lifestyle. With their small, flexible body, they are able to live in various natural crevices of plants (calyx crevice, flowers, etc.), and they also tend to live on the undersides of leaves.

They have piercing-sucking mouthparts with which they pierce and suck out plant cells. When feeding, they prefer young tissue, probably because it is softer and easier to pierce. Thrips do not produce honeydew like aphids, but only deposit dark droplets of faeces.

The abdomen of the females has a drill to pierce the eggs into the plant tissue. The eggs themselves are transparent and practically invisible in the plant tissue. Occasionally, the plants react to the puncture by developing brown corkings, which are then easy to recognise.

Thrips go through two mobile larval stages in their development, an immobile primate and a pupal stage in the soil. A complete life cycle takes about 14 days at 25 °C. This means that melon thrips can develop numerous generations per year.

Host plants

The melon thrips has a very broad food spectrum. It attacks a wide variety of plants from the cucurbitaceae, nightshade, butterfly, orchid and composite plant families.

Distribution

Melon thrips occurs in Africa, Asia, America and Oceania. The European Union is considered to be infestation-free, but it is regularly introduced from tropical regions, mainly via commercial goods.

Spread and transmission

Melon thrips can be introduced very easily via fruit, plants for planting and packaging material. Thrips can spread quickly in the crop due to their good jumping and flying ability. They can be carried by moving air masses to cover greater distances.

Economic importance

Thrips cause direct sucking damage and are carriers of various dangerous plant viruses (tospoviruses). Mass infestation can mean failure of up to 90% of vegetable crops, as this species tends to develop resistance to pesticides. There are fears that the pest could spread uncontrollably in greenhouses after movement to the European Union.

Prevention and control

Since thrips are very small animals, which have a hidden way of life, an infestation is usually discovered late. Therefore, a careful (young) plant control and monitoring by means of blue glue boards is recommended to detect an infestation in time. In addition to approved chemical pesticides (see list of pesticides approved in Austria), some beneficial insects such as predatory mites, predatory bugs or lacewing larvae are suitable for biological plant protection.

In the European Community, the melon thrips is listed as a quarantine pest. The occurrence of the melon thrips or the suspected infestation of host plants by the melon thrips must therefore be reported immediately to the official plant protection service of the respective federal state.

Phytosanitary status

Thrips palmi is listed as a Union Aquatic Pest (UQS) and is thus subject to legal regulations to prevent its introduction and spread into or within the member states of the EU.

Services

Plant Health Services