Taiwan Agricultural Research Institute cautiously sprays Bacillus thuringiensis; the Taiwan Agricultural Chemicals and Toxic Substances Research Institute formulates a pest sex pheromone blend to trap and kill adults, reducing damage from the Asian corn
In addition to breeding work, the Taiwan Agricultural Research Institute has another important task: seed preservation. When researchers at the Taiwan Agricultural Research Institute carry out seed preservation in corn fields, they always encounter serious corn borer problems. In the past, the insecticide chlorpyrifos was sprayed to prevent damage from the Asian corn borer. Because this corn is for seed preservation rather than for eating, there was originally no problem, but the Taiwan Agricultural Research Institute researchers did not want to spray pesticides for control anymore, so they sought help from the Taiwan Agricultural Chemicals and Toxic Substances Research Institute. The Taiwan Agricultural Chemicals and Toxic Substances Research Institute formulated a suitable sex pheromone to mass-trap adults, and during the period only paired it with one spray of a Bacillus thuringiensis formulation commonly used in organic agriculture, successfully suppressing the damage of the Asian corn borer to corn.
1 spray of Bacillus thuringiensis +Sex pheromone trapping and killing of adults Significantly reduces damage from the Asian corn borer to corn fields
In the past 2 years, the Taiwan Agricultural Chemicals and Toxic Substances Research Institute has actively promoted biological pesticides. Biological pesticides mainly include natural materials such as microorganisms and pheromones. At present, more than 20 different pheromone-related products have been developed. The target crop for which the Taiwan Agricultural Research Institute requested assistance is corn. The main pest of corn is the Asian corn borer, and the secondary pest is the beet armyworm. The Taiwan Agricultural Chemicals and Toxic Substances Research Institute formulated an Asian corn borer sex pheromone for use by the Taiwan Agricultural Research Institute. Starting from the small seedling stage of corn, sex pheromone traps were set up, with 40 Asian corn borer traps and 20 beet armyworm traps per hectare, arranged in concentric circles, effectively surrounding and protecting the entire corn field, carrying out mass trapping and killing until the corn was harvested.
Hung Chiao-chen, associate researcher in the Biological Agents Division of the Taiwan Agricultural Chemicals and Toxic Substances Research Institute, said that field trials were conducted for both the spring and autumn crops of corn. In addition to setting up sex pheromone traps, one plot in the autumn crop was sprayed once with Bacillus thuringiensis. The trial results confirmed that the density of the Asian corn borer and beet armyworm could be greatly reduced, and the damage to corn plants from Asian corn borer boring was also greatly reduced. According to the trial data of the Taiwan Agricultural Chemicals and Toxic Substances Research Institute, with the sex pheromone adult trapping and killing area as the experimental area and the conventional pesticide area as the control area, the damage rate of spring corn plants by the Asian corn borer decreased from 92.7% in the control area to 17.1%; the damage rate of autumn corn decreased from 54.7% to 3.4% and 18.1% (there were 2 experimental areas).
The planting area of edible corn in our country is about 15,000 hectares, and the Asian corn borer is its key pest. It bores into the corn ear and stem to feed, causing major losses to corn. The current status of corn borer control is the adoption of integrated pest management. In addition to large-scale release of Trichogramma wasps, granular pesticides are also used, but the granules must be placed in the whorl to be effective, which is quite labor-intensive. If organic corn is being grown, Hung Chiao-chen said, farmers growing organic edible corn told him that large amounts of Bacillus thuringiensis must be sprayed, but Bacillus thuringiensis is a biological control material and its cost is relatively much higher. From the results of the Taiwan Agricultural Research Institute's corn field trials, it appears that sex pheromone trapping and killing of adults combined with one spray of Bacillus thuringiensis can achieve a good control effect, and the cost of organic corn cultivation can be greatly reduced.
Tailor-made sex pheromone formulation specifically for the corn earworm of Kinmen sorghum and other field trials
In addition to corn, the Taiwan Agricultural Chemicals and Toxic Substances Research Institute also tested the control effect of sex pheromones on the main pest of sorghum. Sorghum and corn are closely related gramineous coarse grain crops. The main pest of sorghum is the corn earworm, also known as the tomato fruitworm, which feeds on the sorghum panicle. Once infested, it can also seriously affect the sorghum harvest.
The main production area of sorghum is Kinmen, with a planting area of about 2,000 hectares. When the Taiwan Agricultural Chemicals and Toxic Substances Research Institute cooperated with the Kinmen Quarantine Station to conduct insect trapping trials, it was found that the corn earworm in Kinmen and the same species of pest in Taiwan actually showed geographic differences. Therefore, the original corn earworm sex pheromone formulation of the Taiwan Agricultural Chemicals and Toxic Substances Research Institute had limited effect on the corn earworm in Kinmen, so a sex pheromone formulation was tailor-made for the corn earworm in Kinmen. However, field trials have not yet been conducted.
The Asian corn borer (right in the photo) is the key pest of corn and bores into the corn ear and stem to feed (left in the photo). (Photo / provided by the Taiwan Agricultural Chemicals and Toxic Substances Research Institute)
The Taiwan Agricultural Chemicals and Toxic Substances Research Institute formulated a sex pheromone for the Asian corn borer to conduct adult trapping trials. During the trial period, Bacillus thuringiensis was sprayed only once, but the control effect was good. (Table / Taiwan Agricultural Chemicals and Toxic Substances Research Institute)