In coffee estates, wasp to fight mealybug pests in Kodagu district

The parasitoid can be released across estates during the summer months, which is the breeding time of the mealybugs.
Image used for representational purpose only.
Image used for representational purpose only.

MADIKERI: Coffee plantations are prone to several diseases and the attack from mealybug pests is among the major reasons for crop loss across estates. However, the Coffee Research Sub Station (CRSS) in Chettalli of Kodagu district has come up with a unique and organic way to fight this pest. Leptomastix Dactylopii, a parasitoid, has been developed at the station that will be effective in culling the mealybugs in the most ecofriendly way. “Mealybugs are major pests affecting coffee and they cause considerable crop loss,” explained Dr Manjunath Reddy, Entomologist at CRSS.

Ovalshaped, soft-bodied insects, the mealybugs are a threat to the pepper vines and other fruit trees in the estates too. The bugs breed during summer and cause immense damage to the crops during monsoon. “The bugs are covered with white mealy wax, making it tough to eradicate them.

Leptomastix Dactylopii (left); File photo of a
mealybug-infested coffee plant

They suck a large amount of sap from leaves and stems with the help of piercing mouthparts, depriving plants of essential nutrients,” he explained. There has been an increased buildup of the mealybugs in the estates and the wild in recent times and Dr Manjunath analysed that this might be due to the abiotic changes in climate and environment. While there are a few chemical sprays to fight the mealybugs, they have been proven ineffective as these bugs infest the estates during the monsoon. However, the CRSS has come up with the most organic way to fight these bugs.

The substation has reared Leptomastix Dactylopii, a parasitoid that attacks and hunts mealybugs. “Female parasitoids lay eggs on the third instar (a lifecycle stage) and young adult mealybugs. A single parasitoid emerges from one mealybug. The parasitoid larvae eat the mealybug from the inside out. After 20-30 days, a young adult parasitoid emerges through a hole on the top-end of the dead mealybug,” he detailed.

A female parasitoid lays 300- 400 eggs,which develop into adult parasitoids in 20-30 days. These adult parasitoids have a lifespan of 2-3 weeks. The Leptomastix Dactylopii can be left in coffee estates that suffer from mealybug infestation and 1,000 Leptomastix Dactylopii are required to be released per acre of estate.

The parasitoid can be released across estates during the summer months, which is the breeding time of the mealybugs. The parasitoids are available at the entomology department at the CRSS in Chettalli and they are priced at Rs 250 per 1,000 parasitoids. This method is seen as the most economical and organic way to fight the mealybugs that infest both Robusta and Arabica varieties of coffee plants.

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