Insect Management
Rice Insect Management
Armyworm
Pseudaletia unipuncta (Haworth) (also known as the true armyworm)
Occasional Pests - Crossover Pest From Other Crops From Legumes to Rice
Description
 The
adult is a moth with a wingspan of about 4 to 4.5 cm. The color of the forewings
is brown with a single, small white spot about midway across the width and
length of the wing. The hindwings are gray or gray-brown. Larvae (caterpillars)
can be either green or brown in color but have a distinctive pattern of
longitudinal stripes - a dark stripe along each side and a broad stipe along the
back (dorsal stripe). The dorsal stripe has a fine lighter colored broken line
down the center. The head is pale brown with green and brown mottling.
Distribution
Armyworm occurs throughout the US east of the Rocky Mountains and in AZ, NM,
and CA.
Life Cycle as Related to Wheat and Rice
Larvae often become numerous in wheat just before or shortly after heading.
Often nearly full grown larvae leave wheat fields, especially those field that
are becoming senescent, and move into adjacent rice fields. Damage usually
occurs near the border of the two crops and seldom is a complete rice field
infested. Pupation can occur in the rice field. Adults are not known to deposit
eggs directly onto rice.
Damage and Symptoms
Larvae consume leaves and often eat all above ground parts of the rice plant,
especially if the plants are small.
Scouting and Treatment Thresholds
No formal scouting plan is used for armyworm in rice. Growers are encouraged
to observe rice fields adjacent to wheat for movement of armyworm between the
two crops. Treatment may be necessary if stand reduction is evident.
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