Prionus Beetle Prionus californicus Motschelsky Lure Evaluation and Mating Disruption Studies in Utah Sweet Cherry Orchards
Proposed by: Michael Pace
Presenter: Pace, M. , Agriculture/horticulture Agent, Utah State University, Brigham City, UT 84302
California Prionus beetles have been shown to attack apple, rose, lilac, oak, and hop vines in North America and sweet cherries and peach trees in Utah. The females lay eggs on/in the soil near the base of the host trees where they hatch and move into the soil to feed on the roots of plants for the next 3-5 years. This feeding on the tree roots causes decreased nutrient uptake, water stress, reduced growth, tree decline and mortality, eventually reducing orchard longevity. There are no effective chemical or biological controls listed and current recommendations are to fallow the orchard for 6-10 years. In Utah, the adults (1”-2 ¼” long) emerge from the soil in early July – early September where they mate, lay eggs and die. During this time period they do not feed on plant materials. In 2009, the female-produced sex pheromone of P. californicus Motschulsky was identified and synthesized as (3R,5S)-3,5-dimethyldodecanoic acid by Rodstein et al., J Chem. Ecol. 35: 590-600. In 2009 and 2010, Utah State University Extension tested a 0.1 mg research lure in both panel and bucket traps in Utah sweet cherry orchards. The bucket traps were highly effective in catching the adult beetles over the panel traps. In 2011, we tested a new commercial lure developed by Contech Enterprises and compared it to the research lure. The Contech lure was statistically superior in trapping the adults in comparison to the research lure and lasted for four weeks before needing to be replaced. Pacific Biocontrol developed an Isomate mating disruption (MD) dispenser which was evaluated in two sweet cherry orchards in 2011. The dispenser had an incredible 90% trap shutdown when compared to the control orchards. These studies suggest that the Contech lure and the MD dispensers may provide a management tool option for orchards with Prionus beetle concerns.