The crop

Four varieties, developed by BARI,  of Bt brinjal that are resistant to the fruit and shoot borer.

Eggplant, Solanum melongena L. (also known as brinjal and aubergine) is one of the most important, inexpensive and popular vegetable crops grown and consumed in Asia. Eggplant production provides an important source of cash income particularly for small, resource-poor farmers.

The insect and its damage

The biggest constraint to eggplant production throughout Asia is the chronic and widespread infestation by the eggplant fruit-and-shoot borer (EFSB), Leucinodes orbonalis Guenée. The larvae damage eggplant by boring into the petiole and midrib of leaves and tender shoots rsulting in wilting and desiccation of stems. Flowers are also fed upon resulting in flower drop or misshapen fruits. The most serious economic damage caused by EFSB is to the fruit by producing holes, feeding tunnels and frass (or larval excrement) that make the fruit unmarketable and unfit for human consumption. To control this insect farmers routinely spray insecticides, often 2-3 times per week.

Current control methods for the eggplant fruit and shoot borer (EFSB)

To control EFSB farmers routinely spray insecticides, often 2-3 times per week, and most of these are broad-spectrum insecticides. Such an insecticide-dependent strategy poses both environmental and health concerns. Environmental concerns include killing natural enemies that can help reduce pest populations, leaching into the soil and water, and harming pollinators such as bees. Health concerns include harm to the applicator and farm workers, as well as harm to the consumer from high pesticide residues on the crop. These problems have been documented in Bangladesh and the Philippines.

The Solution

Eggplant has been engineered to produce a protein from a common soil bacterium, Bacillus thuringiensis (Bt). The cry1-Ac protein produced in Bt brinjal is similar in structure and activity to that found in nature and is already available and used commercially in the form of Bt-based biopesticides, often used by organic growers. However, pesticidal sprays are only effective during a brief window then the larva hatches from the egg and bores into the fruit or shoot of the brinjal plant. Once the larvae takes refuge within the fruit they are safe from surface sprays however intensive they may be, and are free to destroy the crop from within. Bt brinjal, in which the cry1-Ac gene is genetically engineered into the brinjal, ensures a built-in resistance against the fruit and shoot borer larvae.