GM eggplant helps farmers reduce pesticide use and increase profits, study finds

By Joan Conrow

December 7, 2020

Bangladeshi farmers significantly reduced pesticide use and increased their profits by growing genetically modified (GM) eggplant, a new study confirms.

Farmers growing insect-resistant Bt brinjal (eggplant) improved their yields by 51 percent and cut pesticide costs by 37.5 percent, according to the study published last month in the American Journal of Agricultural Economics.

“Bt brinjal, a publicly developed GMO [genetically modified organism], conveys significant productivity and income benefits to farmers while reducing the use of pesticides damaging to human and ecological health,” the researchers concluded.

Cultivating Bt brinjal raised yields by 3,564 kilograms per hectare. Bt brinjal farmers are harvesting more eggplant and discarding fewer fruits due to damage, resulting in higher yields, the researchers found.

“Bt brinjal farmers sell more eggplant and receive a higher price for the output they sell while incurring lower input costs, resulting in a 128 percent increase in net revenues,” the paper states.

The researchers, who are based at Cornell University and the International Food Policy Research Institute in Dhaka, also found that “Bt brinjal farmers used smaller quantities of pesticides and sprayed less frequently. Bt brinjal reduced the toxicity of pesticides as much as 76 percent.” Additionally, farmers who had pre‐existing chronic conditions consistent with pesticide poisoning were less likely to report a symptom of pesticide poisoning or incur cash medical expenses to treat such symptoms while growing Bt brinjal.

Smallholder farmers grow brinjal because it is a lucrative cash crop that is popular with consumers. However, the devastating fruit and shoot borer (FSB) pest can damage up to 86 percent of their plants. In an attempt to control the pest, farmers may use pesticides from 23 to 140 times per season, though few take measures to protect themselves and the environment during application.

Bt brinjal — the first genetically modified (GM) food crop adopted for cultivation in South Asia — provides inherent resistance to the FSB.

Researchers based their study on a farm-level cluster randomized controlled trial (RCT). To their knowledge, it was the first study to use an RCT design, which is less vulnerable to concerns regarding selection bias and endogenous placement, to assess the impact of a GM crop in a South Asia setting. Their study sample comprised 1,196 households (598 treatment households and 598 control households) in 200 clusters/villages (100 treatment and 100 control villages), with an attrition rate of 1.7 percent (five treatment households and 15 controls).

“Critics of GM crops claim that GMOs convey no economic, health or environmental benefits while they also ‘pose a serious threat to farmer sovereignty.’ Our results speak directly to these criticisms,” the researchers wrote. “Bt brinjal farmers marketed more output, sold at a higher price, incurred lower input costs, and, consequently, had higher net revenues (by 128 percent). Bt brinjal farmers used smaller quantities of pesticides, sprayed less frequently, and reduced the toxicity of pesticides applied by 42 to 76 percent. All these benefits were derived from an open‐pollinated crop provided by a public agency.”

Researchers found that although Bt brinjal farmers retained more brinjal for home consumption, both because they produced more and discarded less post‐harvest, they sold also 143.6 kg more brinjal than the control group — an impact significant at the 5 percent level. Additionally, Bt brinjal sold at prices 12.6 percent higher than non-GM varieties.

“We note that traders purchasing Bt brinjal knew that it was a GM crop, and, to the best of our knowledge, consumers knew that they were purchasing a GMO food,” the researchers wrote. “A consequence of reduced pesticide application was that Bt brinjal looked better and had no marks of infestation or holes, the skin of the brinjal was much softer, making the food easier to prepare and, according to the respondents in our qualitative fieldwork, tastier.”

To illustrate those points, the researchers included this comment from a market trader: “At the beginning, I could not sell this brinjal in this market; I forced them to take it, especially those who are known to me to come every day. I told them no problem if you do not pay money. Then, when they took the brinjal home and ate it, they told me to give them more brinjal. Since then, demand is getting higher. In fact, it was not sold for two or three days at the beginning. After that, I enticed all of them to buy this. Since then, I did not have any problems.”

Bt brinjal farmers also required less family labor — 250 days, compared to 278 days for control households — primarily because they were able to reduce the number of pesticide applications by 33.6 percent, compared to the control group. The quantity of pesticide used fell by 28.2 percent, while the toxicity of pesticides also declined by 42 percent overall. Farmers growing Bt brinjal and who had pre‐existing chronic conditions were 11.5 percentage points less likely to report a symptom of pesticide poisoning.

“We note three policy implications that follow from these results,” the researchers concluded. “They support the view that GMOs can contribute to the goal of increasing yields while reducing environmental stressors. They provide further justification for releasing Bt brinjal in countries such as India and the Philippines, where these varieties have been developed but not approved for cultivation due to public reservations about GMO foods. They point to the valuable role that public agencies can play in the dissemination of GMOs. The involvement of BARI and the Bangladesh Department of Agriculture in the development and support of Bt brinjal cultivation alleviates concerns raised by anti‐GMO activists regarding farmer sovereignty. Finally, our finding that consumers are willing to pay more for a GM crop is striking; further work understanding why would be of value.”