Banana Rhizome Weevil

The most destructive pest of Musa spp., found in banana growing areas worldwide, is widely distributed. Adult weevils, measuring 10-13 mm in length, have a shiny reddish-brown to black coloration, a long curved snout, and although they are capable of flight, they rarely do so. The grubs or larvae, which are creamy white, stout, fleshy, legless, and wrinkled with a spindle-shaped body, have a red head. The eggs are laid in the collar region or on underground rhizomes.

The grubs bore into the pseudostems and rhizomes, creating tunnels as they feed. Adults also bore into the suckers. Consequently, the central shoots are killed, the plants exhibit premature withering, the suckers die, the fruits remain undersized and are fewer in number. Additionally, fungi and bacteria contribute to the acceleration of rotting. In severe cases, the trees may even break down due to strong winds.

Control

  1. Using healthy suckers for planting is crucial. Planting infected rhizomes can worsen the damage. It is essential to obtain vigorous and uninfested planting material from weevil-free plantations. Before planting, carefully examine the material by slicing it open. If larvae, pupae, or tunnels are found, the material must be destroyed.
  2. Maintaining a clean cultivation practice is important. Ensure that the planting field is free from weeds and remnants of previous plants.
  3. Implementing good husbandry practices, such as proper weeding, appropriate manuring, and mulching, promotes the growth of robust banana plants that are more tolerant to weevil infestations.
  4. Removing pseudostems below ground level is recommended. Instead of continuously harvesting, it is suggested to periodically harvest all mature pseudostems. This preventive measure discourages continuous breeding of the weevils, as there will be intervals with fewer young suckers present.
  5. It is also necessary to eliminate stumps from wind-damaged plants.
  6. For chemical control, one method involves drenching the soil with Ranger when it is most effective. The recommended rate is 40ml of Ranger per 20L of water.

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