AVRDC International Cooperators'
Fact Sheet

Sweet Potato Insect Pests
 

Sweetpotato Vine Borer
Omphisa anastomasalis


Found in Southeast Asia and Hawaii


Damage symptoms

The plant has poor overall growth. There is no full flush of foliage and some plants appear yellow and wilted. The distal portions of some vines dry up and die. Storage root formation is poor and yield is low.


Insect characteristics

Chewing mouthparts. The larvae are cream to light purple. The heads are brown and the undersides of their bodies white. Brown spots form stripes along their sides. Adult moths are white with brown yellow patterns on their wings.


Where to look

Borers are difficult to detect. The major signs of an infestation are the presence of insect frass in the crown of the plant and adult exit holes in the stem. If you see the former, carefully cut the stem lengthwise to expose the larval tunnel. Follow the tunnel to its end and locate the borer.

exit holes in vines
Exit holes in vines
pupa in sweet potato root
Pupa in sweet potato root


Technical information

Adult moths are only active at night when they lay their greenish eggs singly on the leaves and petioles. The hatching larvae bore into the stems and feed internally. Before pupating the larvae bore exit holes in the stem for adults to escape.


Control

Dip sweet potato cuttings in an insecticide solution before planting. This will kill insect eggs on the foliage and stems.

Studies in Taiwan have shown that biweekly insecticidal sprays of deltamethrin around the stems give excellent control. Other insecticides may also be used; contact your local extension agent.

Borer resistant lines are also being developed.
 
Last updated: 2001. 
Information from: Field Guide: Insect Pests of Selected Vegetables in Tropical and Subtropical Asia. 1995. B.L. Parker, N.S. Talekar and M. Skinner. Publication 94-427. Pesticide and other control recommendations should be adapted to local conditions. 

AVRDC Home | Extension Materials Home | Sweet Potato Home