Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 20, 1999
Publication Date: N/A
Interpretive Summary: The tracheal mite and the Varroa mite are important pests of honey bees in most countries of the world, and extensive resistance has been observed to fluvalinate, the only compound registered in the U. S. for control of varroa. Formic acid is used in other countries, but is hazardous to handle because of its corrosive properties, and no companies in the U. S. have been interested in selling it because of potential liability. We have developed a gel formulation which is easier and safer to handle and can be dispensed in pre-filled packets for use in bee hives. This formuilation has been licensed for commercial production, and represents an opportunity for early registration of an alternate material for control of this pest. This work has already attracted considerable interest in the whole beekeeping industry.
Technical Abstract: Formic acid has been used in various countries for the control of parasitic mites of honey bees (Apis mellifera), particularly the Varroa mite (Varroa jacobsoni) and the tracheal mite (Acarapis woodi). Its corrosivity and consequent fear of liability have precluded commercial interest in the United States, and its rapid vaporization requires frequent reapplication. We have developed a gel formulation of formic acid which provides controlled release over 2 ¿ 3 weeks and improves the convenience and safety of handling of formic acid. The strong acidity of formic acid restricts the choice of gelling agents; vegetable gellants like agar are destroyed, and bentonite clay derivatives do not gel, even with high-shear mixing. Polyacrylamides lead to viscous liquids lacking thixotropic properties. Gels with suitable physical characteristics were provided by high-molecular- weight polyacrylic acids and fumed silicas. The polyacrylic acid gels were difficult to mix and gave slower and non-linear release behavior, while the fumed silica gels were easy to prepare and linear in formic acid vaporization.