M. Dehghanizadeh, A. Knagg, A. Romero, F.O. Holguin, C.E. Brewer
New Mexico State University,
Keywords: guayule resin, insect repellents, bio-based insecticides, Blatella germanica, Cimex lectularius
Summary:Guayule (Parthenium argentatum) is a desert shrub native to the southwestern US and one of the main alternative sources of high-quality natural rubber. Processing of guayule for bulk rubber produces two residue streams: a complex resin-rich liquid, and a fine, dry woody bagasse. Identifying value-added commercial applications for these residue streams will reduce the environmental impacts and net costs of rubber production, and increase the economic viability of guayule as an industrial crop. The non-rubber extracts (resin) of guayule contain potential high-value secondary metabolites (sesquiterpene esters, triterpenoids, sterols, and triacylglycerols) with applications in anti-inflammatory drugs, coating and adhesives, termite resistance, antifungal and antimicrobial materials, resin multipolymers, and insecticides. Due to the adverse effects of long-term application of synthetic insecticides on human health and ecosystems, bio-based, nont-toxic insecticides have received a lot of research interest. A recent study in our lab on the characterization of guayule resin showed the presence of mono- and sesquiterpenes, and their oxygenated derivatives (like α- and β- pinene, D- limonene, β-phellandrene, elemene, β-eudesmol), which have been among the active compounds for repellents listed in the literature. Triterpenoids (like argentatins) are another major groups of compounds in guayule resin which have potential repellent activity. In this study, we are testing the toxicity and avoidance efficacy of non-rubber extracts (resins) for guayule as repellents for urban pest insects, starting with the German cockroach (Blatella germanica) as a well-understood model, and working towards testing with bed bugs (Cimex lectularius), which have shown a recent resurgence in North America.