Author
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Hollingsworth, Robert |
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Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 2/14/2005 Publication Date: 6/20/2005 Citation: Hollingsworth, R.G. 2005. Limonene, a citrus extract, for control of mealybugs and scale insects. Journal of Economic Entomology. 98(3):772-779. Interpretive Summary: Mineral oils and insecticidal soaps are commonly recommended at 1-2% active ingredient for control of scale insects and mealybugs on actively growing plants. I discovered that limonene, when properly emulsified, is even more effective for controlling these types of insects. Limonene is the major component of citrus peel oil, produced as a by-product of the juicing industry. I created plant-safe emulsions effective against insects when I mixed the limonene with APSA-80® ("All Purpose Spray Adjuvant"), a non-ionic surfactant, at a ratio of 4 parts limonene to 3 parts surfactant. The addition of 0.1% of a silicone-based agricultural adjuvant (Silwet L-77®) improved efficacy. Whiteflies and aphids were easily controlled with this mixture used at half-strength, while the full-strength mixture controlled from 69 to 100% of mealybugs and scales, depending on the species, insect stage and application method). Limonene is used in a variety of foods and beverages and is classified by the U.S. Food and Drug Administration as a GRAS (Generally Recognized as Safe) compound when used as a food additive or flavoring (USEPA 1994). There are currently no products on the market intended for control of plant pests using limonene as the active ingredient. Limonene damaged certain species of ferns, gingers and delicate flowers. These developed water-soaked areas which later became necrotic. However, limonene solutions caused no damage to ornamentals with thick, waxy leaves, such as palms, cycads, dracaenas and orchids. Limonene has great promise as a safe, natural pesticide for insect pests on actively growing plants. Technical Abstract: Mineral oils and insecticidal soaps are commonly recommended at 1-2% active ingredient for control of scale insects and mealybugs on actively growing plants. I discovered that limonene, when properly emulsified, is even more effective for controlling these types of insects. Limonene is the major component of citrus peel oil, produced as a by-product of the juicing industry. I created plant-safe emulsions effective against insects when I mixed the limonene with APSA-80® ("All Purpose Spray Adjuvant"), a non-ionic surfactant, at a ratio of 4 parts limonene to 3 parts surfactant. The addition of 0.1% of a silicone-based agricultural adjuvant (Silwet L-77®) improved efficacy. Whiteflies and aphids were easily controlled with this mixture used at half-strength, while the full-strength mixture controlled from 69 to 100% of mealybugs and scales, depending on the species, insect stage and application method). Limonene is used in a variety of foods and beverages and is classified by the U.S. Food and Drug Administration as a GRAS (Generally Recognized as Safe) compound when used as a food additive or flavoring (USEPA 1994). There are currently no products on the market intended for control of plant pests using limonene as the active ingredient. Limonene damaged certain species of ferns, gingers and delicate flowers, but caused no damage to ornamentals with thick, waxy leaves, such as palms, cycads, dracaenas and orchids. Limonene has great promise as a safe, natural pesticide for insect pests on actively growing plants. |
