Guayule (Parthenium argentatum)
is an alternative source of natural rubber that grows well in arid
and semi-arid regions. The feasibility of guayule as an industrial
crop is substantially impacted by the value of the rubber extraction
byproducts, resin and bagasse. In this study, guayule resin, a complex
mixture of secondary plant metabolites, was tested as a bio-based
insect repellent. Whole guayule resin and vacuum-distilled resin fractions
were tested against Turkestan cockroaches (Blatta lateralis Walker), both immediately after application and after being allowed
to evaporate for one week. All resin fractions showed good repellency
in their fresh form, with two fractions performing better than the
positive control (citronella Java oil). The heavier resin fractions,
which contain a mixture of lipid and oxygenated sesquiterpenes, demonstrated
a persistent repellent activity against Turkestan cockroach nymphs,
losing only ∼3% of their repellency after 7 days. The vacuum-distilled
fractions were characterized by gas chromatography–mass spectroscopy
and fatty acid methyl ester analysis. Structural similarity analysis
showed that the most abundant compounds in guayule resin overlap with
some active ingredients in commercial repellents. Techno-economic
analysis of guayule resin-based insect repellents showed that a substantial
quantity would need to be produced and sold (∼8% of the U.S.
active ingredient market for residential insect repellents) in order
to achieve the targeted resin selling price of 1.00 USD/kg resin.