ARS | Publication request: Broad Mite (Polyphagotarsonemus latus) infestation and injury in watermelon and potential sources of resistance

Submitted to: HortScience
Publication Type: Abstract Only
Publication Acceptance Date: January 30, 2007
Publication Date: July 2, 2007
Citation: Kousik, C.S., Levi, A., Simmons, A.M., Hassell, R., Shepard, B.M. 2007. Broad Mite (Polyphagotarsonemus latus) Infestation and Injury in Watermelon and Potential Sources of Resistance. HortScience. 42(3):453.

Technical Abstract: During the summer of 2006, we observed severe broad mite (Polyphagotarsonemus latus) injury and infestations on watermelon plant introductions (PI) and commercial cultivars grown in the field in Charleston, SC. Broad mites have previously not been reported on watermelons in the U.S.A. However, they have the potential to emerge as a serious pest. Injury was mainly observed on the growing terminals and the tender apical leaves which were bronzed grew poorly and in some cases distorted and curled upwards. We evaluated 219 PI belonging to the watermelon core collection (GRIN, USDA, ARS, Griffin, GA) for broad mite, injury and infestation that occurred naturally. Nine PI (4%) had no visible broad mite injury in the field compared with a commercial cultivar Mickey Lee which was severely injured. Broad mites were extracted by washing the growing terminals with boiling water and counting the mites under a stereomicroscope. Mickey Lee had higher broad mite counts compared with some of the PI with no visible injury. Fourteen PI were further evaluated in the greenhouse to confirm their resistance by artificially infesting them with broad mites that had been cultured on susceptible watermelon plants. PI in accessions belonging to Citrullus lanatus var. lanatus (PI 357708), Citrullus lanatus var. citroides (PI 500354), Citrullus colocynthis (PI 386015, PI 386016, PI 525082) and Parecitrullus fistulosus (PI 449332) had significantly lower broad mite injury ratings and counts compared with Mickey Lee. These PI may serve as potential sources of broad mite resistance.