Bt eggplant (Solanum melongena L.) in Bangladesh: Fruit production and control of eggplant fruit and shoot borer (Leucinodes orbonalis Guenee), effects on non-target arthropods and economic returns

Authors: PRODHAM, MZH - Bangladesh Agricultural Research Institute; HASAN, MT - Bangladesh Agricultural Research Institute; CHOWDHURY, MMI - Bangladesh Agricultural Research Institute; ALAM, MS - Bangladesh Agricultural Research Institute; RAHAM, ML - Bangladesh Agricultural Research Institute; AZAD, AK - Bangladesh Agricultural Research Institute; HOSSAIN, MJ - Us Agency For International Development (USAID); Naranjo, Steven; SHELTON, ANTHONY - Cornell University

Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/30/2018
Publication Date: 11/21/2018
Publication URL: http://handle.nal.usda.gov/10113/6471020
Citation: Prodham, M., Hasan, M., Chowdhury, M., Alam, M., Raham, M., Azad, A., Hossain, M., Naranjo, S.E., Shelton, A. 2018. Bt eggplant (Solanum melongena L.) in Bangladesh: Fruit production and control of eggplant fruit and shoot borer (Leucinodes orbonalis Guenee), effects on non-target arthropods and economic returns. PLoS One. 13(11):e0205713. https://doi.org/10.1371/journal.pone.0205713.
DOI: https://doi.org/10.1371/journal.pone.0205713

Interpretive Summary: Bangladesh is the first developing country to approve a genetically engineered (GE) vegetable crop for commercial production. Eggplant, or brinjal as it is called in Bangladesh, is a popular and important vegetable that is attached by a serious caterpillar pest called the brinjal fruit and shoot borer (BFSB). The insect causes massive yield losses in Bangladesh of up to 86% and the primary method of control is the application of insecticides, with sometimes as many as 84 sprays being applied during a single growing season. The Bangladesh Agricultural Research Institute introduced 4 varieties of GE brinjal that specifically targets the BFSB. This study is the first replicated trial to examine the efficacy of the new varieties and to gain baseline information on yield, other agronomic characteristics and economics of the crops. Studies also focused on documenting any non-target effects the crops may have on other arthropod pests and on beneficial arthropods important for biological control. Results show that the GE brinjal is highly effective in controlling the BFSB but that some insecticides may still be needed to control other pests not affected by the GE trait. However, none of the 4 varieties of GE brinjal had any negative effects on non-target arthropods and thus pose little to no environmental risk. Results are important in demonstrating the efficacy and safety of the new GE crop as Bangladesh plans to expand adoption and production in the future.

Technical Abstract: Eggplant or brinjal (Solanum melongena) is a popular vegetable grown throughout Asia where it is attacked by the brinjal fruit and shoot borer (BFSB) (Leucinodes orbonalis). Yield losses in Bangladesh have been reported up to 86% and farmers rely primarily on frequent insecticide applications to reduce injury. Bangladesh has developed and released four brinjal varieties producing Cry1Ac (Bt brinjal) and is the first developing country to do so. We report on the first replicated field trials comparing the four Bt brinjal varieties to their non-Bt isolines, with and without standard insecticide spray regimes. Results of the two-year study (2016-17) indicated Bt varieties had increased fruit production and very little BFSB fruit infestation compared with their respective non-Bt isolines. Fruit infestation for Bt varieties varied from 0-2.27% in 2016, 0% in 2017, and was not significantly affected by the spray regime in either year. In contrast, fruit infestation in non-Bt lines reached 36.70% in 2016 and 45.51% in 2017, even with weekly spraying. However, maximum fruit yield was obtained from sprayed plots compared to non-sprayed plots, indicating that other insects such as whiteflies, thrips and mites can reduce plant vigor and subsequent fruit weight. Higher gross return was obtained from the Bt varieties over non-Bt isolines irrespective of spray regime; no spray non-Bt isolines resulted in a negative return in most cases. Statistically similar densities of non-target arthropods, including beneficial arthropods, were observed in both Bt and non-Bt varieties in most cases. An additional trial that focused on a single Bt variety and its isoline provided similar results on infestation levels, with and without sprays, and similarly demonstrated no effect on non-target arthropods. Together, these studies indicate that Bt brinjal is extremely effective at controlling BFSB in Bangladesh without affecting other arthropods. However, to achieve maximum yield of Bt brinjal other pest arthropods need to be managed.