The production of vegetables and ornamentals in European glasshouses is still characterized by an intensive use of pesticides. Resistance problems and environmental concern necessitate a change from chemical control to integrated pest and disease management. During recent years thrips pests, in particular the western flower thrips (Frankliniella occidentalis), have become the number one key pests in many glasshouse crops throughout Europe. Thrips pests are very hard to control with chemical pesticides, treatments have to be repeated frequently and upset the already developed biological control programmes used currently.
The project aims to collect, evaluate and assist in the mass production and commercial application of natural enemies of thrips species. An effective biological control method would not only help the farmer to reduce production costs and at the same time strongly decrease health and environmental risks, it would also safeguard existing IPM programmes for glasshouse crops.
The object of the project was to collect and evaluate the effectiveness of natural enemies of thrips and to assist in the mass production and commerical application of these natural enemies. A survey of predators of thrips in cucumbers, tomato, peppers, beans, lettuce, strawberries and carnation has been conducted in Spain and a number of species identified that feed on Frankliniella occidentalis. Collection in cultivated fields and natural vegetation in the Netherlands, showed that Ceranisus menes, a larval parasitoid of thrips, which is able to develop on Frankiniella occidentalis, occurs in the Netherlands. In the laboratory, biological parameters have been assessed of different strains of C menes using F occidentalis and F schulzel as hosts. In order to estimate the ultimate effectiveness of this parasitoid in the field through laboratory techniques, aspects of host selection were studied by detailed behavioural observations. In Central and South Italy, collections were made of several species of flower bugs (Orius) on different plant species. In the laboratory, 5 species of Orius were reared and the biological performance of each species was studied feeding on Ephestia kuehniella eggs and on F occidentalis.
Development of a biological control method will be conducted in various steps. Collections of natural enemies, predators and parasitoids, will be made in Europe and worldwide. In order to investigate their potential, selection criteria developed earlier will be used, using biological and behavioural characteristics. Experiments to test the pest control capacity will first be carried out in the laboratory, followed by tests in experimental glasshouses and finally in commercial glasshouses and in the field.