2018 ASHS Annual Conference

The yellowmargined leaf beetle (YMLB) is a major insect pest of brassicas across the southeast and has increased in occurrence in Alabama where crop devastation can easily exceed 50 percent. YMLB is native to South America and it was first detected in Mobile, USA, in 1947. Two researchers at Auburn University (R. Balusu and H. Fadamiro) along with collaborators at the University of Florida (O. Liburd) initiated a YMLB research projects in 2010 that gradually added an educational component with Alabama Extension Commercial Horticulture Program to rapidly disseminate pest alerts and management information. With increasing number of small farms growing winter crops in Alabama, the threat of YMLB has also increased significantly since 2010 with many reports of crop failure and produce contamination. At present, organic insecticides alone do not provide adequate crop protection due to strong migration pattern and rapid buildup of YMLB. Adults and larvae of YMLB can defoliate turnips and Napa cabbage in a few days followed by movement to other brassica crop or weedy hosts. Since YMLB is strongly attracted to turnips, it can be used as a trap crop in conjunction with biorational insecticides to become a true integrated pest management (IPM) strategy. Based on small-plot research, the extension IPM team developed large-scale trap crop test plots that serve as demonstration areas for grower education. Based on multi-year studies, there is evidence that two to four rows of early-planted turnips as a perimeter trap crop is very effective in attracting YMLB adults away from a main crop like cabbage, where YMLB control gets complicated due to plant structure and need for complete coverage of crop with bioinsecticides. Research into the efficacy of individual organic bioinsecticides since 2010 has now diversified into replicated plots for testing complex organic insecticide rotations and tank-mixes. While natural pyrethrin (PyGanic) and spinosad (Entrust) have shown adequate effectiveness against YMLB, additional effective materials such as Monterey Garden Insect Spray (a General Use Pesticide with spinosad) and Grandevo (Chromobacterium subtsugae strain PRAA4-1) appear to slow down defoliation. Integration of above insecticides with Bacillus thuringiensis-based formulations is promising for growers facing multiple insect threats, e.g., caterpillars and YMLB. Audience members attending the talk will be provided copies of major educational publications (scouting field guide, IPM slide charts, and bulletins) as examples of IPM education and communication strategy for the statewide program that continue to evolve and assist small producers save high-value crops.