Pesticide-free eggplants to benefit farmers, consumers

Producing pesticide-free eggplants in the Philippines is now possible, according to field-trial reports released for the first time by the Institute of Plant Breeding-University of the Philippines Los Baños (IPB-UPLB).

The IPB-UPLB field trial showed that Bacillus thuringiensis (Bt) eggplant exhibited “superior performance” in controlling the fruit and shoot borer (FSB). It involved testing of five open pollinated varieties engineered to produce from the bacterium Bt, a protein called “Cry1Ac.”

Cry1Ac effectively functions as the insecticide that kills the moth FSB when ingested by the pest.

The experiments were done over three eggplant seasons from 2010-2012 in the Philippines’s biggest eggplant producer—Pangasinan. The province accounts for 18 percent of the country’s eggplant area and more than 30 percent of the country’s eggplant output.

An ability to stamp out FSB by up to 100 percent was observed in the Bt eggplant varieties tested on actual fields in barangays Paitan and Santa Maria in Pangasinan. These are fields conventionally infested heavily by the FSB moth particularly during the dry season.

But IPB scientists did not use any lepidopteran (moth)-specific insecticide during the three trials—both for the Bt eggplant and the non-Bt eggplant.

All throughout three trials, the superior efficacy of Bt eggplant in stopping by virtually 100 percent infestation of FSB was observed in the three eggplant varieties tested—Dumaguete Long Purple, Mara, and Mamburao. All three varieties—unsprayed by insecticides—were planted both for Bt eggplant and non-Bt eggplant.

“These results demonstrate that Bt eggplant lines containing Cry1Ac event EE-1 provide outstanding control of FSB and can dramatically reduce the need for conventional insecticides,” said the IPB scientists, led by Desiree M. Hautea.

“Bt eggplant lines demonstrated high levels of control of FSB shoot damage [98.6 percent to 100 percent] and fruit damage [98.1 percent to 99.7 percent] and reduced FSB larval infestation (95.8 percent to 99.3 percent) under the most severe pest pressure during Trial 2,” they added.

In contrast, the non-Bt eggplant suffered 41.58-percent FSB-damaged shoots, 93.08-percent damaged fruits and 16.15 larvae per plot per harvest.

Even when moth’s eggs have been found in the Bt eggplant fruits, the eggs did not survive to form viable fruit-boring insects.

“Under such severe pest pressure, the Bt eggplant lines showed less than 1 percent EFSB shoot damage, less than 2 percent fruit damage and fewer FSB larvae at less than 11 larva per plot per harvest,” the scientists said.

“Commercial production of Bt eggplant has great potential to reduce yield losses to FSB while dramatically reducing the reliance of growers on synthetic insecticides, reducing risks to the environment, to worker’s health and to the consumer,” they added.

The IPB Filipino breeders’ team also included Lourdes D. Taylo, Anna Pauleen L. Masanga, Maria Luz J. Sison, Josefina O. Narciso, Reynaldo B. Quilloy and Randy A. Hautea. It had guest scientists from the Cornell University-New York, Frank A. Shotkoski and Anthony M.Shelton.

Their report was filed with the peer-reviewed Journal Public Library of Science (PLOS).

Farmers perennially spraying insecticide on eggplants have suffered from endless health complaints, such as redness of eyes, skin irritation such muscle pains and headaches due to the spray.

FSB has been most notorious for misshaping and destroying eggplant fruits.

Their most destructive damage are the holes, the tunnels they bore within the eggplant along with the frass (larval excrement) they leave in the fruit—making it dirtily
unmarketable.

Insecticide spraying using profenofos, triazophos, chlorpyrifos, cypermethrin and malathion is the only resort of farmers. Manual removal of the pest or the damaged fruits and wilted shoots has been found ineffective.

The use of arthropods and pheromone traps as biological control has been ineffective. Traditional breeding also failed in controlling FSB.

But the control of pests through Cry1Ac expression into the eggplant through the introduction of the human-safe bacterium Bt has earlier been proven on cotton and corn.

It is the eggplant’s turn to be benefitted by the technology—consequently bringing cleaner, tunnel-free, pesticide-free eggplants for farmers and consumers.

“After more than 40 years, conventional breeding has not produced any commercial variety of eggplant conferring high level of resistance to the FSB. Therefore, efforts became focused on developing Bt eggplant that expresses the same Cry1Ac protein as the cotton,” the scientists said.

The success of the Bt technology in corn and cotton has been widely accepted globally by farmers. As of 2014 the Bt technology has been planted on 78.8 million hectares in 28 countries, “predominantly by resource-poor farmers.”

-Published in BusinessMirror.  See original article link here.