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Pests and Diseases
Noni Aphids

melon aphids
ABOVE: melon aphids (Aphis gossypii) on a noni leaf.

aphids on fruit

ABOVE: Long-legged ants tending aphids and feeding on flower nectaries on young noni fruit.

citrus aphids

ABOVE: Citrus aphids on noni petioles; here the aphids are tended by long-legged ants.

adult and juvenile melon aphids
ABOVE: Close-up of adult and juvenile melon aphids.

aphids on leaves

ABOVE: Aphid colony feeding on young noni leaves. Young leaves are curled and distorted due to heavy feeding by the aphids.

 

 

 

Aphids are sap-feeding insects. Their feeding damage to noni is usually not significant, but can result leaf distortion or the formation of black sooty mold on noni leaves.

Pest: Aphids, the melon aphid (Aphis gossypii). Aphids are most often associated with and tended by one of several ant species.

Damage: Aphids are sap-feeding insects that cause stunting and slow growth of noni plants and leaf curling and deformity if aphid populations are large. The sugary waste product that is excreted from aphid abdomens provides a substrate for the growth of a saprophytic fungus that causes “sooty mold”. If ants and aphids can be controlled, the sooty mold usually disappears after a short time.

Distribution: Melon aphids are widely distributed throughout all of the major Hawaiian islands. Aphid population outbreaks are favored at warm, dry locations or during warm, dry periods of the year.

Impact: Aphids have the most negative impacts on the growth of noni seedlings in nurseries.

Control:
  1. Biological control. In some environments, aphids are controlled effectively by natural enemies (e.g., lady beetles, aphid lions) and parasitic fungi.
  2. Spay applications of approved insecticidal soaps and oils.
  3. Ant control. If ants are controlled effectively, aphid populations generally decline.
  4. Hand removal and destruction of severely infested leaves and stems.
  5. Weed control or elimination of alternate hosts for aphids.
  6. Wind breaks.
Notes: Aphids were not previously reported as a pest of noni in Hawaii or elsewhere in the world. Be advised that heavy use of insecticides may eliminate populations of beneficial insects.



Last Updated on December 7, 2006