Submitted to: HortScience
Publication Type: Peer reviewed journal
Publication Acceptance Date: 4/5/2005
Publication Date: 10/10/2005
Citation: Lopez, R., Levi, A., Shepard, B., Simmons, A.M., Jackson, D.M. 2005. Sources of Resistance to Two-spotted Spider Mite (Acari: Tetranychidae) in Citrullus spp. Hortscience. 40:1661-1663. Interpretive Summary: Watermelon is an important crop in many parts of the world, however pests and diseases cause extensive damage to this crop in the U.S. The two-spotted spider mite is an important pest that can deform leaves and flowers, stunt plant growth, and reduce yield of watermelon. Watermelon plants that are resistant to spider mites would be useful in controlling this pest. Wild relatives of watermelon that grow in Africa and Asia are a potential source of resistance to two-spotted spider mite. To find useful plant genes, ARS and Clemson University scientists evaluated plants of different wild watermelon species. A group of plants that have resistance to the two-spotted spider mite was identified. These plants will be used in future breeding programs to add spider mite-resistance to the cultivated watermelon.
Technical Abstract: The two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), often causes serious damage to watermelon (Citrullus sp.) crops. To help protect this crop, there is a need to evaluate and identify watermelon germplasm that may be useful in enhancing plant resistance against T. urticae. Watermelon cultivars (Citrullus lanatus var. lanatus), and United States Plant Introduction accessions (U.S. PIs) of C. lanatus var. citroides and C. colocynthis were evaluated for resistance to T. urticae. In open-choice experiments in a greenhouse and in laboratory rearing cages, T. urticae preferred watermelon cultivars, Citrullus lanatus var. lanatus PIs, and C. lanatus var. citroides PIs considerably more than C. colocynthis PIs. All watermelon cultivars and PIs were highly susceptible to T. urticae infestation, while the C. colocynthis PIs were resistant. The C. colocynthis PIs may be useful sources for improving T. urticae resistance in cultivated watermelon.