Volatile Organic Compounds from Cassava Plants Confer Resistance to the Whitefly Aleurothrixus aepim (Goeldi, 1886)

SIMPLE SUMMARY: Cassava (Manihot esculenta Crantz; Euphorbiaceae) plants have a long lifecycle. They remain in the field for at least 10 months and are exposed to numerous pests. Seventeen groups of pests that affect this crop have been identified. These include 35 species found in the Americas, 11 in Africa, and 6 in Asia, totalling approximately 200 arthropod species that feed on cassava. Whiteflies are considered one of the main pests of cassava worldwide. In northeastern Brazil, the most common whitefly species causing severe damage to cassava is Aleurothrixus aepim (Goeldi, 1886) (Hemiptera: Aleyrodidae). Cassava plants emit volatile organic compounds and secrete extrafloral nectar; these substances may be essential for developing biological control strategies against pests. Herein, we describe variations in the blend constitution and individual concentrations of constitutive volatile organic compounds released by two cassava genotypes. Additionally, we highlight the activity of a monoterpene, considering that the resistant genotype emitted higher concentrations of this compound. ABSTRACT: Cassava is an essential tuber crop used to produce food, feed, and beverages. Whitefly pests, including Aleurothrixus aepim (Goeldi, 1886) (Hemiptera: Aleyrodidae), significantly affect cassava-based agroecosystems. Plant odours have been described as potential pest management tools, and the cassava clone M Ecuador 72 has been used by breeders as an essential source of resistance. In this study, we analysed and compared the volatile compounds released by this resistant clone and a susceptible genotype, BRS Jari. Constitutive odours were collected from young plants and analysed using gas chromatography–mass spectrometry combined with chemometric tools. The resistant genotype released numerous compounds with previously described biological activity and substantial amounts of the monoterpene (E)-β-ocimene. Whiteflies showed non-preferential behaviour when exposed to volatiles from the resistant genotype but not the susceptible genotype. Furthermore, pure ocimene caused non-preferential behaviour in whiteflies, indicating a role for this compound in repellence. This report provides an example of the intraspecific variation in odour emissions from cassava plants alongside information on odorants that repel whiteflies; these data can be used to devise whitefly management strategies. A better understanding of the genetic variability in cassava odour constituents and emissions under field conditions may accelerate the development of more resistant cassava varieties.