Ben TreMore than 200 million parasitic wasps were raised and released by the authorities in the context of nearly 600 hectares of coconuts damaged by blackhead worms.
The information was given by Mr. Vo Van Nam, Director of the Ben Tre Department of Crop Production and Plant Protection on December 11. The number of bees is released in batches in districts and cities. The two main species of parasitic wasps kept are Habrobracon hebetor and Trichospilus pupivorus.
The authorities will raise parasitic bees and worm larvae in the laboratory. After the parasitic bees hatch, they will put them in plastic bottles with holes cut into them and hang them on coconut tree trunks in the garden.
Parasitic wasps are raised in the laboratory and then released into the coconut garden. Image: Nam An
According to Mr. Nam, the female bee’s instinct when encountering black-headed worm larvae in the wild will be to inject paralyzing toxins and then lay eggs on the body. After about half a month, each parasitized blackhead worm will hatch 10-50 young bees. On average, a female bee lives for more than 20 days and lays about 100 eggs.
Last year, Ben Tre also released more than 370 million parasitic wasps to kill blackhead worms.
Mr. Nam said the province has more than 80,000 hectares of coconut trees, currently about 600 hectares of gardens are infected with blackhead worms. Thanks to the application of parasitic wasp release, some coconut areas in Mo Cay Nam district, Thanh Phu have begun to recover at a rate of about 70%.
Authorities often take advantage of the rainy season to release parasitic wasps because this is a favorable season for this species to develop, while it is an unfavorable season for black-headed worms.
To effectively kill blackhead worms, the Ben Tre Department of Crop Production and Plant Protection recommends that people clean their gardens, clean up, prune and destroy leaves damaged by worms. After spraying pesticides for two weeks or more, parasitic bees can be released. From this point on, farmers need to stop spraying to protect the bees.
Blackhead worm causes damage to a coconut leaf in Ben Tre. Image: Nam An
The black-headed worm’s scientific name is Opisina arenosella Walker, Originated from India and Sri Lanka. Worldwide, insects have been recorded in 16 countries. Because the age of larvae is up to 40 days compared to 10-30 days for other pests, when they are in a certain place, they will eat it all, causing mass plant death.
Ben Tre province has coconut garden area accounting for 80% of the coconut area in the West and 50% of the coconut area in the country. More than two-thirds of people in this locality (800,000 people) rely on income from coconut trees to stabilize their family economy. Four years ago, blackhead worms began appearing in the province, then spread throughout the area, causing the heaviest damage, causing about 1,000 hectares of coconuts to be infected.
Nam An