|
Class |
Insecta |
|
Order |
Lepidoptera |
|
Family |
Pterophoridae |
During severe infestation, considerable defoliation of plants may occur
resulting to reduction in storage root yield.
Philippines.
The larvae feed on the young shoots, preferring unopened leaves. The young
larvae feed on the upper epidermis of unopened leaves leaving the lower
epidermis intact. This initial damage can be mistaken as caused by the
brown leaffolder, Ochyrotica concursa Wals.,
which also attacks young shoots. However, leaf damage caused by the brown leaf
folder turns brown while that of white plume larva does not change colour. Older larvae feed right
through the leaves producing numerous holes, sometimes eating the entire leaf
blade leaving only the petiole.
Egg. The egg is hemispherical, white when newly laid and turns greenish
when about to hatch.
Larva. The
greenish first and second larval instars
have long white hairs arising from tubercles throughout the body. Later instars
have shorter hairs with black hairs alternating with white hairs and the body colour
changes to yellowish green. Mature larvae measure 8.5 mm.
Pupa.
The pupa is rectangular with pointed abdominal tip and covered with whitish
hairs. The dorsal part is dark green while the ventral part is light green. It
has small black spots on the lateral side and two black dorsal markings. The
average length is 6.5 mm.
Adult. The adult is a small (7-8 mm)
white moth with feather-like white wings.
The eggs are laid on either side of the leaf. These
eggs are attached to the leaf surface by a cementing substance secreted by the
female. A female can lay from 25 to 130 eggs during an oviposition period
of 2 days. The insect undergoes 5 larval instars lasting 2 to 4 days per
stadium. The total larval period ranges from 8-18 days. Pupation lasts for 3-5
days. The total life cycle ranges from 15-28 days. Longevity of adults is 3-4
days. Male to female ratio is 1.0:1.5.
Only Ipomoea triloba and I. aquatica are considered alternate
hosts.
Biological control
The larva is attacked by a brachonid parasite, Apanteles sp.
Chemical control
Infestation in the field is low and does not warrant any chemical control.
Amalin, D.M. and Vasquez, E. A. 1993. A handbook on Philippine sweet potato
pests and their natural enemies. International Potato Center (CIP), Los Baņos,
Philippines. 82 p.
Gapasin, D.P. 1981. Biological studies of sweet potato insect pests and their
natural enemies. Terminal Report. A research study funded by the Philippine
Council for Agriculture and Resources Research (PCARR). Department of Plant
Protection, Visayas State College of Agriculture. 210 p.
Vasquez, E.A. and
Sajise, C.E. 1990. Pests of sweet potato: Insects, mites and diseases.
Philippine Root Crop Information Service, Philippine Root Crop Research &
Training Center. 65 p.
Contributed by: Erlinda
Vasquez and
Vilma Amante |
