Effectiveness of Agave genotype extracts applied alone or mixed with mineral oil against the cactus scale mealybug Diaspis echinocacti (Hemiptera: Diaspididae)

Abstract

Synthetic insecticides used in the management of the mealybug Diaspis echinocacti (Bouché, 1833) (Hemiptera: Diaspididae) can contaminate co-products from this plant. The use of Agave extracts and/or mineral oil is a sustainable alternative to reduce the residual effect of these chemicals in the palm production chain. The objective here was to determine the effectiveness of Agave genotype extracts applied alone or mixed with mineral oil against the cactus scale mealybug D. echinocacti. Two experiments were carried out to achieve this goal. The first one aimed to select the most promising Agave genotype extract concentration (CL80) to kill 80% of the first instar mobile nymphs of D. echinocacti (Experiment 1), and the second to determine the effectiveness of the selected extract against nymphs, pupae, and adults of different ages of this mealybug in laboratory and greenhouse (Experiment 2). The extract of the genotype Agave fourcroydes cv. Cabinho with lethal concentration (LC80) of 10.9 mL/10 mL is the most efficient in causing mortality of D. echinocacti. The lethal concentration of the A. fourcroydes cv. Cabinho killed 80% of the first instar motile nymphs and more than 74% of the nymphs, pupae, and adults of different ages of D. echinocacti in the laboratory and greenhouse followed by Agave sisalana cv. Tatuí 3. Furthermore, the mortality of this scale mealybug was higher with applications of mineral oil (Assist), alone or mixed with sisal extracts.