Compatibility and interaction betweenBacillus thuringiensisand certain insecticides: perspective in management ofTuta absoluta(Lepidoptera: Gelechiidae)

Abstract

Bacillus thuringiensis var. kurstaki (Berliner) has been suggested as a biological control agent for Tuta absoluta (Meyrick). The objective of this study was to determine the interaction between abamectin, azadirachtin, indoxacarb chlorantraniliprole, dichlorvos and metaflumizone with Bt. Effect of recommended doses of the chemical insecticides on colonization of Bt was also investigated in culture medium. Except for metaflumizone, none of the chemicals tested reduced the colonization of Bt compared with control. Interaction between Bt and the chemical insecticides on 2 nd instar larvae was also assessed. In interaction tests, Bt was applied at LC50 * Corresponding author: mjhejazi@tabrizu.ac.ir, Downloaded by [UQ Library] at 02:03 03 February 2015A c c e p t e d M a n u s c r i p t 2 level, 0, 12, 24 or 36 h after treating the larvae with LC10 or LC25 of the chemical insecticides.An antagonistic effect was observed in all treatments where Bt was applied immediately after the chemical insecticide. Also, antagonism was observed when treatment with Bt was done 12 h after azadirachtin and metaflumizone applications. Applying Bt 12 and 24 h after treatment with LC25 of chlorantraniliprole, dichlorvos and abamectin resulted in synergism. But, synergism with LC10 of dichlorvos and abamectin was observed only after 12 h. Additive effect was observed in the rest of the time and concentration combinations. Based on the results obtained, simultaneous use of the chemical insecticides tested and Bt is not recommended for T. absoluta control; and an appropriate time interval should be taken into consideration accordingly.

Efficacy of some biorational insecticides against Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) under laboratory and greenhouse conditions in Kuwait

“…The high efficacy could also plausibly be due to a synergistic interaction between the biopesticides, by complementarily increasing the sensitivity of the pest (Wraight, & Ramos, 2017), although this hypothesis has not been tested in the present study. Similar to this study, high efficacy of Azadirachtin when combined with B. thuringiensis against T. absoluta (Abd El-Ghanny et al, 2018;Amizadeh et al, 2015;LO-Bue, 2012) or with B. bassiana against T. absoluta (Klieber & Reineke, 2016;LO-Bue et al, 2012) and army worms (Spodoptera litura) (Mohan, Reddy, Devi, Kongara, & Sharma, 2007) Studies carried out by other authors also demonstrated lower efficacy of S. feltiae on T. absoluta (Turkoz & Kaşkavalci, 2016) and other insect pests (Lezama-Gutierrez et al, 2006). Lezama-Gutierrez et al (2006) Virulence of EPNs is affected by different larval stages; and the low efficacy of S. feltiae in the laboratory experiments is presumably because the treatment was targeted at the less susceptible stage of the pest (i.e., second instar larvae) ( Van-Damme et al, 2016).…”

“…The high efficacy could also plausibly be due to a synergistic interaction between the biopesticides, by complementarily increasing the sensitivity of the pest (Wraight, & Ramos, ), although this hypothesis has not been tested in the present study. Similar to this study, high efficacy of Azadirachtin when combined with B. thuringiensis against T. absoluta (Abd El‐Ghanny et al, ; Amizadeh et al, ; LO‐Bue, ) or with B. bassiana against T. absolut a (Klieber & Reineke, ; LO‐Bue et al, ) and army worms ( Spodoptera litura ) (Mohan, Reddy, Devi, Kongara, & Sharma, ) has been documented. For example, LO‐Bue et al () observed that the combined use of 300 cc/hL of Azadirachtin and 150 cc/hL of B. thuringiensis on tomato provided over 85% control of T. absoluta in open field experiments, with the pest severity reduced to a level comparable to that of synthetic insecticides.…”

Synergistic interaction between carvacrol and Bacillus thuringiensis crystalline proteins against Cydia pomonella and Spodoptera exigua

“…Additionally, we have shown that carvacrol applied via ingestion is toxic to lepidopteran caterpillars. Although there are studies on the toxicity of mixtures of B. thuringiensis and plant products against pests (Abedi et al 2014;Amizadeh et al 2015;Nouri-Ganbalani et al 2016), none of them concern the use of carvacrol as a component of these combinations. Our study is in line with the search for effective biological plant protection products and harmonizes with IPM programs.…”

Tomato Leafminer, Tuta absoluta (Meyrick 1917), an emerging agricultural pest in Sub-Saharan Africa: Current and prospective management strategies

“…Currently there are many commercially available bacterial and fungal formulations for controlling pests including T. absoluta in America and Europe (Sabbour, 2014). The formulations are either by foliar spray or by drenching the roots (Amizadeh et al, 2015). One of the best and successful formulations was that of Metarhizium anisopliae (fungus) and Bacillus subtilis (bacteria) which have been reported to reduce the population of T. absoluta on tomato at all developmental stages in America and Europe ( nanl et al , 2012).…”