INSECTICIDAL PROPERTIES OF SEVERAL MONOTERPENOIDS TO THE HOUSE-FLY (DIPTERA, MUSCIDAE), RED FLOUR BEETLE (COLEOPTERA, TENEBRIONIDAE), AND SOUTHERN CORN-ROOTWORM (COLEOPTERA, CHRYSOMELIDAE)

House flies, Musca domestica (L.), and their eggs were treated with 22 monoterpenoids to determine the topical, fumigant, and ovicidal activ ity of each compound. Fumigant activity of 14 monoterpenoids were exam ined further using red flour beetles, Tribolium castaneum (Herbst). Th ird-instar southern corn rootworm, Diabrotica undecimpunctata howardi Barber, were treated with carvacrol, citral, citronellal, menthol, pul egone, verbenol, and verbenone to determine their activity on larvae. Structure-activity relationships were evaluated with the toxicity data . We made comparisons between monocyclic aromatic, acyclic aliphatic, monocyclic aliphatic, and bicyclic aliphatic alcohols, ketones, aldehy des, and acids to determine toxicity differences involving the skeleta l structure, amount of saturation, and associated functional groups of monoterpenoids. Ketones were more effective than alcohols in the topi cal, fumigant (T. castaneum), and ovicidal bioassays and less toxic th an an analogous aldehyde in the topical, fumigant (M. domestica), and ovicidal bioassays. Aldehydes were more toxic than alcohols in the top ical and fumigant (M. domestica) bioassays. In the topical and ovicida l bioassays, aromatic or acyclic alcohols, or both, were more effectiv e than monocyclic and bicyclic alcohols. Vapors of bicyclic ketones we re more toxic than monocyclic ketones to adult M. domestica. Monoterpe noid alcohols containing three carbon-carbon double bends were more ef fective than saturated alcohols in the topical and larval bioassays. A monounsaturated ketone was more toxic than a structurally similar sat urated ketone and two di-unsaturated ketones when it was applied topic ally to adult M. domestica. A saturated monocyclic ketone inhibited eg g hatch more effectively than unsaturated monocyclic ketones.