Estudio preliminar del efecto acaricida de seis extractos metanólicos sobre la arañita bimaculada, Tetranychus urticae Koch

Abstract

Acaricide effect of six methanolic extracts prepared from Ñaca (Baccharis tola Phil.), Chana (Chuquiraga atacamensis OK.), Lampaya (Lampaya medicilis Phil.), Kipa (Fabiana dense Remy), Umatola [Parastrephia lucida (Meyen) Cabr.] and Yareta (Azorella compact Phil.) was evaluated on two-spotted spider mite, Tetranychus urticae (Acari: Tetranychidae) under laboratory conditions. Applications were direct and residual type using a Potter spray tower. Ñaca (2.5% w/v) and Umatola (1.5% w/v) extracts showed the highest acaricidal activity by direct contact with a 94% mortality, whereas Yareta and Chana extracts (both at 5% w/v) showed 100% egg mortality. The only extracts that showed mortality greater than 50% by the residual contact were Yareta and Chana (both 10% w/v). All extracts showed a repellent effect which was decreasing over time, except for Kipa extract that remained difererencias highly significant after 72 hours post-application. The decreasing susceptibility order calculated using LC50 through Probit analysis was yareta>umatilla>kipa>lampaya>ñaca>chana.