UPLB researchers develop new approach vs eggplant pest

MANILA, Philippines - Eggplantis one of the most important vegetable crops in the Philippines. In fact, its value is one of the highest among vegetables at P1.9 billion, according to the Philippine Statistics Authority.

Production reached 78,760 metric tons compared to last year’s 76,360 MT. It could still go up, if not for the deadly threat known as eggplant fruit and shoot borer (EFSB).

The shoot borer has been one of the most lethal insect pests, attacking flowers, buds, young shoot tips, stems, and fruits. Losses attributed to shoot borer ranged from 50 to 75 percent.

Farmers’ first defense against the pest infestation is an immediate application of synthetic insecticides, which are being sprayed almost three times a week with an average application of 58 times per cropping season, and applying about 41 liters of pesticides. The frequent application of synthetic insecticides is costly.

The average pesticide cost to the total material inputs was estimated at 55 percent, which is much higher compared with other vegetable crops.

Aside from this, the use of synthetic insecticides is strictly prohibited in the organic crop production system, hence only non-chemical control methods are allowed to be used.

Using a science-based approach, the University of the Philippines Los Baños College of Agricultureundertook a study to evaluate and enhance the effectiveness of different control methods that were reported to be effective against EFSB.

Funded and supported by the Bureau of Agricultural Research, the study selected at least three best control methods that were found effective.

Several non-chemical control methods were found to contribute in the reduction of EFSB population. Among these methods include the release of trichogramma, mulching with rice straw and releasing of earwig, intercropping with lemon grass, spraying of botanical insecticides, sanitation, and use of sex pheromone.

Although these methods were found to reduce the population of shoot borer, the level of control is still quite low resulting in a relatively high percentage of damaged fruits.

Each of the component control method was found effective against EFSB during the first year and was integrated and evaluated in two experiments in organic farms in Brgy. Bautista, San Pablo.

Recently, however, based on the laboratory results and preliminary evaluation in ratooned eggplant in San Pablo City, the spraying of neem crude leaf extracts was found highly effective against EFSB as it reduced the EFSB fruit damage to about 20 percent compared to the previous 50 percent EFSB infestation.

The researchers replaced oregano withneem crude water extract. Neem also reduced eggplant phomopsis infection. 

The group will do more research on the earwigs or ground insects, which are considered as general predator of garden insect pests like aphids, mites, pupae of pests, among others.

Like earwigs, trichogramma is a minute wasp thatis an endoparasitoid of insect eggs and is also an efficient killer of many lepidopteran pests.

On the other hand, langkauas is a tall, leafy, perennial herb, and aside from its health benefits, it is also being used as botanical insecticide while neem is widely used in India since the plant exhibited antifeedant and insect growth regulatory effects against several insect pests.