Evaluation of the Compatibility of Coragen and Star Anise, Illicium verum extract with Brevibacillus laterosporus and Their Mixtures against the Larvae of the Cotton Thistle Worm, (Erias insulana) Under Laboratory Conditions

Atiyha, S.K., S. Khalaf, M.S. Mansor and A.A. Hassan. 2024. Evaluation of the Compatibility of Coragen and Star Anise, Illicium verum extract with Brevibacillus laterosporus and Their Mixtures against the Larvae of the Cotton Thistle Worm, (Erias insulana) Under Laboratory Conditions. Arab Journal of Plant Protection, 42(1): 55-66. https://doi.org/10.22268/AJPP-001220 The study was conducted to evaluate the combined effect of Coragen and star anise, Illicium verum extract together with Brevibacillus laterosporus against the larvae of Earias insulana and to diagnose it phenotypically and molecularly. Homology level of 99.86% of the sequences of the gene cytochrome oxidase C (secondary unit 1) of the investigated insect with the sequences of this gene of the insect E. insulana isolated from the Philippines and registered under the international number JX303976.1 and the insect was registered in the global gene bank under the global number OP482241.1. Results obtained showed that the combined effect of Coragen and star anise extract I. verum with B. laterosporu caused a significant increase in the numbers of bacterial colonies, reaching 145.25 and 85.88 bacterial cells/ml when the pesticide was used at the recommended concentration and below the recommended concentration, and 73.91, 66.08, 46.95, 30.43 and 18.26 bacterial cells/ml with star anise extract for concentrations of 5, 4, 3, 2 and 1 ml/L. The interaction of bacteria treatment only at a concentration of 1.9×1010 bacterial cells/ml and Coragen at a concentration of 300 ppm and star anise extract at a concentration of 5000 ppm gave the highest mortality rates of 63.33, 70.0 and 80.0%, respectively, five days after treatment. When the same concentrations above were used, the mortality rate seven days after treatment reached 70.0, 90.0 and 80.0%, respectively, whereas no mortality was recorded for the treatment of bacteria and extract at a concentration of 1.9x106 and 1000 ppm one day after treatment. The results of the interaction of the pesticide concentration with bacteria and anise extract at a concentration of 300 ppm showed the highest mortality rate of 100%, followed by the interaction of the pesticide with bacteria at 300 ppm, which amounted to 93.33%, whereas the interaction of the mixture of star anise extract with Bacteria at a concentration of 5000 ppm had the lowest mortality rate of 86.66% after seven days of treatment. The results of the study showed that the molecular diagnosis of E. insulana gave the highest similarity of 99.83% with the insect strain from Finland. This is the first molecular diagnosis of this insect in Iraq. Results obtained showed that Coragen and star anise extract gave a significant increase in the numbers of B. 65 Arab J. Pl. Prot. Vol. 42, No. 1 (2024) laterosporus. Whereas insect mortality rate increased following the exposure period of seven days, suggesting a high efficiency of the combined effect of the pesticide and extract with the bacteria towards the control of E. insulana, as an important IPM component. Keywords: Brevibacillus laterosporus, Coragen, Star Anise, Plant extract, llicium verum, Cotton boll spiny worm, Earias insulan