A Feeding Deterrent for the Boll Weevil, Anthonomus grandis, from Tung Meal12

Abstract

A substance that deters feeding of the boll weevil, Anthonomus grandis Boheman, was found in the filtrate of a water extract of tung meal, a byproduct of the process of extracting oil from the seeds (nuts) of the tung tree, Aleurites fordii Hemsl. The same substance (or a related substance) was present in more concentrated form in tung oil. The deterrent effect of the substance (s) was greater than that produced by a water extract of calyxes From buds of Rose-of-Sharon, Hibiscus syriacus L. The substance is readily soluble in water, resistant to moderate and volatilizes slowly. A 2- to 15-fold decrease occurred in the number of feeding punctures made by boll a weevils (compared with the controls) when cotton squares (buds) were dipped in a filtrate of water homogenized with tung meal that had been expeller-extracted. This deterrent effect was less when a filtrate of a homogenate of water and meal extracted by using hexane as a solvent was used and was greater when pure tung oil was used. In studies of serial dilution, the increase in deterrent effect was directly proportional to the increase in concentration of the filtrate. Antennectomy of boll weevils did not reduce the deterrent effect.