Toxicity of Ethanolic Extracts from Lippia origanoides and Gliricidia sepium to Tetranychus cinnabarinus (Boisduval) (Acari: Tetranychidae)

摘要

Botanical compounds with insecticidal and acaricidal activities have been used in pest management with different levels of success. Toxicity of ethanolic extracts obtained from wild oregano (Lippia origanoides) and gliricidia (Gliricidia sepium) to Tetranychus cinnabarinus (Boisduval) were evaluated. Mite population was collected from black bean plants growing in Urachiche Municipality Yaracuy State, Venezuela. Ethanolic extracts of wild oregano and gliricidia leaves were evaluated at different concentrations (5, 10, 15, and 20%) using the leaf disk immersion technique. The presence of alkaloids, flavonoids, phenols and tannins, essential oils and saponins was verified in the plant material used in our study. Tetranychus cinnabarinus oviposition decreased at a rate of 43.7% or 57% when 5% oregano or gliricidia extracts were used, respectively. Also, 10% oregano or gliricidia extracts caused 42.2% or 72.5% of mortality to T. cinnabarinus, respectively. Ethanolic extracts showed acaricidal effects on T. cinnabarinus, as evidenced by maximum mortality (96.6% and 100% caused by wild oregano and gliricidia, respectively) when used at a concentration of 20%. Our results showed that gliricidia and wild oregano are promising for the management of T. cinnabarinus, although their field efficacy remains to be evaluated.