Increased moisture at the surface also increases disease incidence in the population. Because of the feeding habits of the pale western cutworm, fewer larvae are necessary for severe damage to result. These cutworms cut the plant off below the soil surface by notching or completely severing the stem. If these tillers can be easily pulled and no roots are attached, the damage is probably from the pale western cutworm. Since the cutworms habitually eat only a small portion of the plants they cut, their potential for significant damage is greatly increased.
Damage often continues along a row or expands in patches until few tillers are left.
Severe infestations can completely destroy a stand. Later, as these areas are destroyed, the cutworms move out into the surrounding areas. Early feeding by small larvae or feeding on other crops such as sugarbeets or corn appears as shot holes or ragged edges on the leaves. The primary tool available is scouting the field to be aware of the cutworm situation. In alfalfa, army cutworms will feed at the soil line on the developing new leaves just as they are emerging.