Development of New Integrated Biological Control Technique against Western Flower Thrips Infesting Chrysanthemum in Korea

The western flower thrips (WFT), Frankliniella occidentalis, are known as a pests on leaves, buds, and petals of horticultural crops and flowering plants, including chrysanthemum. The WFT lays its eggs in plant tissue. After egg hatch, there are two larvae stages and two pupa stages that both occur in the soil. It makes so difficult to chemical control. New integrated biological control technique is being developed to improve biological control of WFT on chrysanthemums. Combinations of biological control agents could be made more cost-effective if used selectively on "trap plants" attractive to WFT. WFT was attracted to White and yellow than pink flower chrysanthemum. In olfactometer studies, of the four color patterns plants for WFT, compared to yellow flowers, white flowers were attractive to WFT adults. The toxicities of 9 commercial pesticides(5 insecticides and 4 fungicides) which have been used in the domestic market were evaluated to WFT at the recommended concentration. The tests were performed according to the standard test method of the IOBC/WPRS working group "Pesticides and Beneficial Organisms". Among 9 pesticides tested with adults of Orius laevigatus, Machine oil 5.0%, Acetamiprid 28.9%, Clothianiclin 20.1%, Mancozeb 29.4%, Benomyl 17.5%, Defenoconazole 26.5%, Bitertanol 9.0% were very low toxicity except Methidathion 41.5% and Deltamethrin 53.7%, with eggs of Orius laevigatus were very low toxicity except Machine oil 97.2% as well. It may be suggested from these results that 7 pesticides could be incorporated into the integrated WFT management system with "trap plants" on chrysanthemum.