Bioefficacy of neem based produc ts (Azadirachta indica A. Juss.) in the management of Oligonychus punicae (Acari: Tetranychidae) in eucalyptus

Abstract

Natural products have shown potential in the control of pest arthropods, as well as for mites of the genus Oligonychus. This study aims to evaluate the toxicity, repellency and ovicidal effect of different commercial formulations based on neem (Azadirachta indica A. Juss.) in the control of Oligonychus punicae (Hirst) in a clonal mini-garden of eucalyptus. The tested products were Natural Neem®, Off-Neem®, NimI-GO® and Azamax®. To evaluate the toxicity on adult females of Oligonychus punicae were used leaf discs of eucalyptus, sprayed with different concentrations of the solution, defined from preliminary tests. Mortality was assessed 48h after application of the products and lethal concentrations (LC50 and LC95) were calculated for each of them. The repellent effect was verified through a choice test, using leaf discs treated with the products and distilled water. The concentration used was the LC50 of the products calculated in the toxicity test. The ovicidal effect was determined by applying the solutions prepared with the LC95 of each product on Oligonychus punicae eggs in eucalyptus leaf disks. The LC50 s ranged from 0.10 to 0.56% for Off-Neem® and Azamax®, respectively, and the LC95 s from 0.71 to 1.78% for Off-Neem® and Natural Neem®. The insecticides Off-Neem® and Natural Neem® significantly reduced the number of Oligonychus punicae females, however Azamax® and Nim-I-GO® did not show a significant reduction, although all were classified as repellents. Oligonychus punicae eggs treated with the LC95 of the products were not viable, with no hatching. It is concluded that the tested natural products showed potential for the control of Oligonychus punicae due to the significant toxicity on eggs and adult females.