Morotsbladloppan, Trioza apicalis : en litteraturgenomgång, kvalitativa intervjuer och ett fältförsök

Abstract: One of the most severe pests on carrot is the carrot psyllid, Trioza apicalis, Förster, which causes curling of the carrot leafs and reduction of plant growth. The carrot psyllid hibernates on conifers and migrates to the carrot field in the spring were reproduction takes place. The symptoms are caused when the adult insects feed on the plants. Plants that are attacked gain an appearance that is similar to parsley. The symptom is caused by a systemic toxin substance in the saliva of the carrot psyllid. The aim with this paper is to gather knowledge about the carrot psyllid, by studying scientific reports and by qualitative interviews with carrot producers. With help of the gained knowledge a strategy to control the carrot psyllid was developed and tested. The strategy involved a trap crop in combination with an upstanding insect net. The results from the qualitative interviews showed that the problem differed between producers. The producers situated in a large carrot district and with a long history of producing carrots had have a problem during a longer time compared with producers situated in areas with few other carrot producers. Most of the producers experience that the carrot psyllid attack from the field edges. One producer experienced that the attack was massive and not only on the edges. Closeness to conifer forests, other carrot fields and areas sheltered from wind are experienced to influence the size of the attack. No differences in attacks have been noticed between different carrot cultivars. In integrated production of carrots the main strategy is to use pesticides. Most of the producers use the pesticide Decis and the number of applications varies between producers. Between 0-2 applications per season are applied generally. One producer uses up to 6 applications. In the organic production four main strategies are mentioned, to sow late, to move the carrot fields long distances between seasons, to cover the field with fibre cloth and to grow trap crops. A trap crop combined with an upstanding insect net was tested. The results showed that the trap crop had an effect. Large amounts of carrot psyllids were trapped. The net on the other hand did not give the expected effect to stop a distribution of the carrot psyllid in to the carrot crop.