Common name
Common cutworm
Scientific name
Spodoptera litura (Fabricius)What it does
Young caterpillars of cutworm eat the soft leaves of the rice plants. Fully grown cutworms can consume the entire plant.
Why and where it occurs
The monsoonal rains favor the development of this insect pest. Likewise, the presence of alternate hosts contributes to the insect’s abundance.
Outbreaks of the pest often occur after periods of prolonged drought followed by heavy rains.The insect occurs in all types of rice environments during the vegetative stages.
The adult moths are nocturnal and highly attracted to light traps. During the day, they hide at the bases of rice plants and grassy weeds.
The eggs usually hatch in the early hours of the morning. Neonate larvae feed on the leaf tips or from the base of the leaf toward the apical area. At daytime, the larvae are found under leaf litter in the ground in dryland fields. In wetland environments, the larvae usually stay on plants above the water surface.
How to identify
To identify cutworm damage, check for
- cut seedlings cut at bases
- skeletonized leaf surfaces
- consumed whole rice plants
The defoliation or feeding damage caused by cutworms can be confused with other defoliators or leaf-feeding insects. To confirm cause of damage, check rice plant for presence of eggs and feeding larvae. Visually inspect for presence of cut seedlings and eaten leaves
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How to manage
- Keep fields flooded
- Encourage biological control agents: scelionid and braconid wasps (egg parasitods), grasshoppers, fungal and polyhedrosis viruses
- Use insecticides like pyrethroids, when larval populations are extremely high (Note: Since pyrethroids can also cause secondary pests, spot spraying only at high population densities is advisable)
Learn more
View full fact sheet: Cutworms on IRRI Rice Knowledge Bank