Effectiveness of Commercial Plant Extracts in Management of Plutella xylostella (Lepidoptera: Plutellidae) on Broccoli in Mexico

Plutella xylostella. (L.) (Lepidoptera: Plutellidae) is the primary pest of broccoli (Brassica oleracea var. italica von Plenck), and it holds the distinction of having the highest number of documented cases of insecticide resistance among insect pests, which complicates its management. The utilization of plant extracts is considered an alternative approach. Therefore, this study aimed to determine the efficacy of commercial plant extracts for the control of P. xylostella. Nine commercial extract products were evaluated, and their effects were compared with Inex-A® + distilled water (control group) and Exalt® (commercial control). Toxicity assays were conducted using third-instar larvae by topical application bioassay. Oviposition inhibition was assessed along with adult female repellency by exposing females to treated surfaces. To determine the residual effect on feeding and oviposition inhibition, third-instar larvae and 3- to 6-d-old adult females were used, respectively, with residual effects measured at 2, 4, 6, 8, and 10 d postapplication. Nimicide 80 (Ultraquimia, Morelos, Mexico) exhibited a mortality rate of 35% of third-instar larvae. Garlimax (Plant Health Care, Azcapotzalco, Mexico) inhibited oviposition by 80%, and demonstrated 85% repellency. The residual effect of Garlimax persisted for 4 d, resulting in a reduced percentage of the consumed area and egg oviposition. The findings of this research highlight the effectiveness of these two products, Nimicide 80 and Garlimax; however, field evaluations are recommended to verify the consistency of their biological effects.