Ahmad Moeini-Naghade, Aziz Sheikhigarjan, Naser Moeini-Naghadeh, Abbas Ali Zamani,
Volume 9, Issue 3 (5-2020)
Abstract
Tomato leaf miner, Tuta absoluta (Meyrick), is a serious pest of the greenhouse in Iran. Chemical control is the main method in high infestation conditions to deal with this pest. In this study, the efficacy of five insecticides from different groups consisting of abamectin, spinosad, imidacloprid, indoxacarb and cypermethrin was examined on the egg, larvae and adult stages of T. absoluta in laboratory conditions. The LC50 values of the insecticides were estimated at the larval stage. The results showed that abamectin had the most and imidacloprid had the least ovicidal effect. None of the tested insecticides had a satisfactory effect on the adult stage. The maximum adulticide impact was 40% for spinosad. Abamectin with 0.45 mg ai.l-1 of LC50 value had the most toxicity and imidacloprid with 980 mg ai.l-1 of LC50 value had the least toxicity on the third instar larvae. According to the findings, abamectin and spinosad had the highest toxicity against three developmental stages (egg, larvae and adults) of the pest and can be used in infested tomato fields, when all life stages of T. absoluta are present at the same time. Meanwhile, it is recommended to use selective insecticides such as indoxacarb, when natural enemies are very active or the population of the tomato leaf miner is mostly at the larval stage.
Nayereh Hamedi, Azade Farazmand, Peyman Namvar, Vahid Farhangi,
Volume 13, Issue 3 (12-2024)
Abstract
Tetranychus urticae Koch is one of the most important vegetable pests in greenhouses. Due to the high reproduction rate and rapid development, T. urticae has a propensity for developing resistance to many classes of pesticides. One method for delaying the occurrence of pest resistance is the application of pesticides with different modes of action. The present research was performed to compare the efficacy of some acaricides against this notorious worldwide pest. The treatments were bifenazite (Kanecide 24% SC at 200 and 300 ppm), spirodiclofen + abamectin (Envidorspeed® 24% SC, 500 ppm), spiromesifen (Oberon® 24% SC, 500 ppm), bromopropylate (Neoron® 25% EC, 1500 ppm), and control (water spraying) based on randomized complete block design with three replications during the summer of 2018 in three provinces of Iran. To determine the spraying time, 30 leaves were collected randomly from each treatment, and if there were an average of 5 active mites under leaves, spraying was done. After spraying, sampling was performed in 3, 7, 14, and 21-day intervals by collecting 30 leaves from each experimental unit. In the laboratory, different developmental stages were recorded using a stereomicroscope. Results showed that the highest efficiency was on the 7 and 14 days after spraying with Envidorspeed® 500 ppm in all provinces. However, this difference wasn't significant in Tehran. In Kerman, Kanecide® 200 ppm, with an efficiency of 94.3% after 21 days, and Envidorspeed® 500 ppm, with an efficiency of 96.19% after 14 days, were the most effective chemicals. Results of these three provinces demonstrated that the efficiency of all five treatments after 14 days was more than 72%. The main purpose of this experiment is to compare the efficiency of these acaricides. All of them provided significant control in the greenhouse, and it could be recommended for population management of T. urticae. However, Envirospeed® in Tehran and Qazvin, as well as Envidorspeed® and Kanecide® in Kerman, are more suggestible based on mortality.
