California's Rose Nurseries Test IPM Techniques Successfully

California nurseries produce two-thirds of the cut roses grown in the United States, with a wholesale value of $45 million. Pest control options have been limited in the past, resulting in the heavy use of pesticides and increasing resistance in important pests such as western flower thrips and two spotted spider mites.

An Integrated Pest Management (IPM) program has been successfully developed in California greenhouse cut roses. The IPM test program was directed at the key pests of cut roses, and was based on fixed precision sampling plans, thresholds, biological control, directed sprays of reduced risk pesticides, and cultural control. This program represented the largest effort to date to implement an IPM program in U.S. floriculture. This project was initiated in 2000 with major funding from the Pest Management Alliance Program of the California Department of Pesticide Regulation. Eight growers spanning the major rose-producing areas of California (San Diego, Santa Barbara and Santa Cruz counties) participated in the program.

The key pests of cut roses are twospotted spider mites (Tetranychus urticae), western flower thrips (Frankliniella occidentalis) and rose powdery mildew (Sphaerotheca pannosa rosae).

Heavy pesticide use against key pests in the greenhouse has resulted in the widespread development of pesticide resistance in western flower thrips.

SOURCE OF THE FULL REPORT: californiaagriculture.ucop.edu