Short and long term effects of some bio-insecticides on Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) and its coexisting generalist predators in tomato fields

Abstract

Tomato leaf miner, Tuta absoluta Meyrick (Lepidoptera: Gelechiidae), is one of the most destructive pests of tomato in many parts of the world including Iran. Field studies were conducted to determine the short and long term effects of Bacillus thuringiensis var Kurstaki (Bt), azadirachtin (AZ), a mix of AZ + Bt, and indoxacarb, as a current chemical insecticide, on T. absoluta larvae. Also, effects of the insecticides were studied on the coexisting generalist predators, Coccinella septempunctata L., Chrysoperla carnea Stephens and Syritta sp. Sampling of T. absoluta and its coexisting generalist predators were performed 1 day before treatment (DBT) and one, 5, 8, 14 and 19 days after treatment (DAT). The results indicated significant short term effect of indoxacarb on the pest larvae. Indoxacarb reduced T. absoluta density and damages. Bt, AZ and mixture of them significantly suppressed the larval density at 19 DAT and caused significant reduction in leaf, stem and fruit damage. The highest long term effect on the pest abundance and damage were observed in Az + Bt caused 100% reduction in fruit and foliage damage compared to the control. The highest and lowest adverse effects on C. carnea, C. septempunctat and Serrita sp. were observed in indoxacarb and Bt treatments, respectively. Findings of this study imply that the mixture of Az + Bt has the highest selective toxicity on the pest and the lowest effect on its coexisting generalist predators.

Evaluation of Bio-Pesticides against the South American Tomato Leaf Miner, Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) in India

“…Similarly, the application of Bt and Neem Azal separately, and in combination, had provided a promising alternative to chemical control [11]. The highest long-term effect on the pest abundance and damage was observed by Nazarpour et al (2016) [52], in azadirachtin + Bt, which caused a 100% reduction in fruit and foliage damage compared to the untreated control. Since we also recorded better efficacies for the neem and B. thuringiensis formulations in the current study, the combined use of those bio-pesticides may be considered for the better control of T. absoluta in field conditions.…”

Effectiveness of bio-insecticides and mass trapping based on population fluctuations for controlling Tuta absoluta under greenhouse conditions in Albania

“…Reports from various authors present contradictory results regarding the effectiveness of Indoxacarb and Bt. Derbalah et al (2012) reported that Indoxacarb had higher efficacy than Bt, while a study conducted by Nazarpour et al (2016) reported the opposite results. In the present study, Indoxacarb was more effective than Bt at reducing the infestation in tomato leaves/fruits.…”

Efficacy of Certain Pesticides Against Larvae of Tomato Leafminer, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae)

“…Chemical pesticides such as Chlorant-raniliprole, Chlorfenapyr, Indoxcarb, Chlofenapyr mixed with Indioxcarb, Spinosad, Spinosad mixed with Abamectin, Emamectin benzoate and Imidacloprid provide excellent control against insect while a biopesticide B. thuringiensis provides moderate control. Nazarpour et al, (2016) indicated that Bt, Azadirachtin and mixture of them significantly suppressed the larval density and caused 100% reduction in fruit and foliage damage compared to the untreated plants. Microbial biopesticides acts as a solution as they are environmentally safe, self perpetuating in nature, specific to target pests etc.…”