Effect of Magnolia alejandrae on Oligonychus punicae Females

Abstract

The avocado brown mite (ABM), Oligonychus punicae Hirst (Trombidiformes: Tetranychidae) causes significant damage to avocado ( Persea americana Mill.). The damage from ABM feeding causes partial and total defoliation, which increases the risk of sunburn on young fruits, and fruit abortion, which can reduce the yields by 20\%. The primary method of controlling ABM is through synthetic pesticides. Therefore, there is a need to study other strategies to control O. punicae that have a lower impact on humans and the environment. This study evaluated the effect of different concentrations of an ethanolic extract of Magnolia alejandrae Garcia-Morales \& Iamonico (Magnoliaceae) leaves on O. punicae females. The different concentrations of the extract did not cause mortality in ABM females, but they did reduce the egg-laying capacity, food intake, and population growth of the avocado brown mite females. At 24 h, the oviposition inhibition percentage ranged between 9.1\% (0.05\% v/v) and 82.3\% (10\% v/v). At 48 h, it was among 17.0\% (0.05\% v/v) and 79.3\% (10\% v/v). At 72 h, among 14.9\% (0.05\% v/v) and 82.1\% (10\% v/v), and at 96 h, 9.8\% (0.05\% v/v) and 89.1\% (10\% v/v), compared to the control group. The extract inhibited ABM damage in a range of 13.0\% (0.1\% (v/v)) to 80.9\% (10\% (v/v)) compared to the control group. The ethanolic extract of M. alejandrae leaves can potentially reduce the damage of O. punicae.