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Gypsy Moth Regulatory Control Methods

The gypsy moth, Lymantria dispa, is an invasive insect that devastates forests in North America. Several methods have been used to control the insect populations, but with little success. New technologies, however, continue to emerge. They include genetically modifying trees with insecticides, spraying leaves with essential oils and introducing pathogens to attack the moths.

  1. Essential Oils

    • A study published in the November 2008 issue of "Bioresource Technology" identified an essential oil from Ocimum basilicum to prevent the feeding of second instar gypsy moth larvae. The researchers identified 37 compounds from the essential oil and stated that linalool was the most predominant. The study found that they could interrupt feeding with linalool at the same rate as a commonly used insecticide, Bioneem. However, unlike Bioneem, larvae were repelled by linalool after five days. The authors concluded that the use of linalool makes a suitable substitute insecticide for the control of gypsy moths.

    Genetically Modified Trees

    • Genetically modified poplar trees have been used to control gypsy moths. A research paper in the October 2010 issue of the "Journal of Insect Science" described a modified poplar tree that was enhanced with a gene from a spider that is toxic to the Asian gypsy moth. The researchers isolated a gene, omega-ACTX-Ar1, from the spider, Atrax robustus, and expressed it in the poplar, Populus simonii. The intent is to prevent the growth and reproduction of the gypsy moth through the use of the toxin from the spider. The study reported that mortality was high, but not complete, for the moths feeding on the leaves of the tress.

    Microorganisms

    • A microorganism, microsporidia, is a pathogen of the gypsy moth that is common in Europe, but is not found in North America. A September 2010 study appearing in the "Journal of Invertebrate Pathology" suggested introducing the pathogen to control gypsy moths. The researchers tested the pathogen in fields in Slovakia using a spray with low concentrations of microsporidia and monitored them for two years. The study reported that microsporidia have a limited host range and suggested that this application may be beneficial for controlling the gypsy moth populations in North America.

    Bacterial Pathogens

    • A strain of bacteria, Bacillus thuringiensis, has been used as an insecticide throughout Florida to control gypsy moth populations. A study published in the April 2011 issue of "Environmental Toxicology and Chemistry" investigated the effects of B. thuringiensis on non-target birds that use the gypsy moth as a food source. The study found that the population of the worm-eating warbler, Helmitheros vermivorous, was decreased by consuming the bacteria meant to keep the population of gypsy moths under control. The researchers concluded that the use of non-toxic insecticides, such as B. thuringiensis, should be evaluated for risk to other species.

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