New, Highly Destructive Spider Mite Present in Southern California

• Published in: Journal of Economic Entomology
• Main Authors: Oatman, E. R., Fleschner, C. A., McMurtry, J. A.
• Format: Text
• Language: English
• Published: Oxford University Press 1967
• Subjects: Articles; Pechora; Mite
• Online Access: http://jee.oxfordjournals.org/cgi/content/short/60/2/477; https://doi.org/10.1093/jee/60.2.477

A potentially highly destructive spider mite, Tetranychus Marianne Gregor, was first reported in California infesting nightshade, Solarium sp. near San Bernardina in August 1965. The mite was found at Riverside, California, in June 1966, infesting lily-of-the-valley vine, Sal pechora rhomboids Mires. Both solanaceous hosts were severely damaged, resulting in considerable mortality. Subsequent greenhouse tests indicated that solanaceous plants were preferred hosts with tomato, Irish potato, eggplant, silver leaf nightshade ( Solarium elaeagnifoliun ), and lily-of-the-valley vine being killed within 3 to 5 weeks after being infested with mature T. Marianne females. Similarly infested bell pepper, cotton, and castor bean plants were only lightly injured. Similar results were obtained when the tests were conducted outdoors. By September, infestations were generally widespread on plants at the University of California Citrus Research Center and Agricultural Experiment Station, Riverside, being found on wild nightshade, and experimental plantings of tomato and exotic Solanaceae, with severe damage and mortality frequently occurring. Predators were noticeably absent on heavily infested plants. Preliminary life-history studies of T. Marianne revealed that a generation from egg to egg was completed in 8 days, and that an average of 16 eggs per female per day was laid by 25 field-collected females during a 5-day period, when reared on Irish potato plants in the in sectary at 82°F and 50% RH.