Submitted to: Citrus Industry
Publication Type: Trade Journal
Publication Acceptance Date: 6/1/2009
Publication Date: 7/1/2009
Citation: Stelinski, L., Rogers, M., Lapointe, S.L. 2009. Citrus Leafminer Mating Disruption. Citrus Industry. 90(7):8-9. Interpretive Summary: The citrus leafminer, Phyllocnistis citrella, is a major world wide pest of citrus production. Larval feeding within serpentine mines damages leaves, which can result in reduced growth rate of young trees. Furthermore, wounds caused by leafminer feeding predispose trees to infection by citrus canker, responsible for blemished fruit, premature fruit drop, and tree decline. Leafminer damage heals slowly thereby increasing the period of susceptibility to the bacterium and contributing to its spread and severity throughout the feeding galleries. Larvae are difficult to control with foliar insecticides because they are protected within the leaf tissue. As a result, insecticides applied for leafminer often fail to control all of the life stages present; thus, damage can reappear 2-3 weeks after treatment. The leafminer's sex-attractant pheromones are a blend of chemical signals emitted by female moths that guide males to females for mating. Calling females can attract males from distances of 40 yards or more. Mating disruption is the insect control practice of deploying synthetic pheromones into the crop atmosphere to interfere with normal mate finding. The effect of mating disruption is to confuse male leafminers by masking or interfering with the females’ natural pheromone trails. Mating disruption is non-toxic to beneficial organisms because pheromones are released at very small quantities and are highly species-specific. Mating disruption appears to be an excellent option for control of citrus leafminer and associated citrus canker disease.
Technical Abstract: Mating disruption targets a specific pest and has no negative impact on natural enemies, the environment, or agricultural workers. A flowable wax dispenser was tested for releasing the female sex pheromone of the citrus leafminer, Phyllocnistis citrella. These dispensers are biodegradable, inexpensive, and easy to produce. Also, they can be applied either by hand or with custom-made mechanical applicators mounted to tractors. Currently, ISCA Technologies, Riverside, CA, holds patent rights to this technology, which is called SPLAT (Specialized Pheromone and Lure Application Technology). The product developed for the citrus leafminer is labelled SPLAT-CLM. In a 2007 spring and summer initial field trial of citrus leafminer control with the recently identified pheromone, very promising results were obtained. Male citrus leafminer capability of locating a source of pheromone was disrupted by deploying pheromone dispensers, with the highest disruption (>99 %), achieved with 370 dispensers per acre. Furthermore, leafminer damage was reduced by more than half, even though insecticides were not applied throughout the season. Following this “proof of concept” investigation, we began developing citrus leafminer mating disruption into a practical tool that can be deployed economically on a large scale. To accomplish this goal, we partnered with ISCA Technologies (Riverside, CA), which develops and markets pheromone release devices for pest control.