Managing Vineyard Insect and Mite Pests
Climbing Cutworms
The name “cutworm” is applied to a large number of larvae of lepidopterous species in the family Noctuidae. The larvae are called cutworms because they climb vines and feed upon foliage, buds and shoots (See Figure 22.1).
Symptoms
Damage to grapevines occurs from bud swell to when shoots are several inches long. Only during bud swell are cutworms able to inflict serious damage to a vineyard. Injured buds may fail to develop canes or clusters, which can cause significant yield reduction in some varieties. When primary buds are destroyed, secondary buds emerge.
Life Cycle
Cutworms usually overwinter through several stages (instars) as feeding larvae (caterpillars) in the soil, or under debris in the vineyard. When temperatures become warm in early spring, the larvae become active emerging at night to feed on winter annual weeds.
Monitoring
Monitoring for cutworms should begin during bud swell in early spring. Because cutworm infestations are localized, many vines must be examined to detect their presence. Newly planted vines need special protection. Frequently the disturbance of weeds or other cover in the planting process leaves little food for resident cutworms.
Cultural Pest Control
Removing weed-dominated ground covers during spring is often followed by major damage to grapes because it can cause movement of cutworms to the grapevines.
Biological Pest Control
Natural enemies of cutworms include predaceous or parasitic insects, mammals, parasitic nematodes, pathogens, birds, and reptiles.
Biorational Pest Control
Microbials
Success, Entrust, and SpinTor can be used which contain the active ingredient spinosad, which is derived from a naturally occurring soil dwelling bacterium called Saccharopolyspora spinosa.
Chemical Pest Control
Control is usually achieved by applying broad-spectrum insecticides. Sevin (carbaryl), Leverage (imidacloprid), Lorsban (chlorpyrifos) and Danitol/Brigade/Baythroid (pyrethroids) are labeled for use against cutworms along with several more selective materials such as Altacor (chlorantraniliprole), Delegate (spinetoram), and Belt (flubendiamide).
Applying Control Materials
Timing of spray treatments is very important since cutworm larvae, once they have become active in the spring, can cause serious bud damage in a short time.
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