Potential of Commercial Biorational and Conventional Pesticides to Manage the Ruellia Erinose Mite in Ornamental Landscapes.

Abstract

<i>Acalitus simplex</i> is an eriophyoid mite pest of the ornamental plant <i>Ruellia simplex</i>. <i>Acalitus simplex</i> compromises the esthetics of <i>R. simplex</i> by inducing erinea formation. Management practices for <i>A. simplex</i> are currently lacking. This study assessed the potential of commercial biorational (citric acid, potassium salt of fatty acids, garlic, thyme, and mineral oil) and conventional (abamectin, fenpyroximate, bifenthrin, spiromesifen) pesticides under laboratory conditions, using two types of spray applications: (A) curative, after erinea formation, and (B) prophylactic, before erinea formation. In the curative application, abamectin, garlic oil, and mineral oil were most effective; in the prophylactic application, abamectin and mineral oil showed the highest efficacies. Abamectin and mineral oil were further tested under greenhouse conditions. Both treatments effectively controlled <i>A. simplex</i> by preventing erinea formation over a four-week post-application period, regardless of the application type. At the end of the experiment, mites were extracted from <i>R. simplex</i> plants. In the curative application, significantly fewer mites were extracted from abamectin and mineral oil treatments than in the control. In the prophylactic application, mites were absent in abamectin and mineral oil treatments but present in the control. Abamectin and mineral oil can be used to manage <i>A. simplex</i> in landscapes.