Beginner

Scientific Name
            Euxoa messoria

Identification
Larvae

• grey-brown with narrow dark band on either side
• 30 to 36 mm long and 5 mm wide
• curl up tightly when disturbed
• feed during the night and hide during the day in the soil or debris  

Adults

• Brownish grey moth about 2.5 cm long

Damage

• Varies from small transparent “windows” in the young leaves to complete defoliation except for the main veins
• Can be variable across the planting
• Damage is only significant in young plantings (2 to 3 years old)
• Loss of buds and leaves on new vines can retard growth and delay fruiting

Often Confused With
Flea beetle damage:  feeding larvae are visible during the day

Japanese beetle: feeding at the top of the grape canopy and damage occurs later in the summer

Period of Activity
Late spring to early summer, approximately a 3 week period. Cutworms feed at night and are not visible during the day.

Scouting Notes
Look for damage to the foliage in young vineyards. These vineyards should be scouted regularly from bud break to shoot lengthening period, particularly after warmer nights. During the day  larvae can be found in vineyard soil beneath debris and stones and in weed clumps.  You will only see the larvae feeding on vines only if you scout at night. Significant amounts of damage can occur over a period of two or three days when the nights remain warm, and it is especially important to monitor for damaged foliage frequently during this time.

Threshold
New vines planted in untreated land previously in pasture are prone to damage, and larvae are often sheltered and somewhat confined within the protective milk cartons or sleeves placed around new vines. They should be closely inspected in spring for signs of damage and treated when necessary.

Advanced

Scientific Name
            Euxoa messoria

Identification
Larvae

• grey-brown with narrow dark band on either side
• 30 to 36 mm long and 5 mm wide
• curl up tightly when disturbed
• feed during the night and hide during the day in the soil or debris  

Adults

• Brownish grey moth about 2.5 cm long

Damage

• Varies from small transparent “windows” in the young leaves to complete defoliation except for the main veins
• Can be variable across the planting
• Damage is only significant in young plantings (2 to 3 years old)
• Loss of buds and leaves on new vines can retard growth and delay fruiting

Often Confused With
Flea beetle damage:  feeding larvae are visible during the day

Japanese beetle: feeding at the top of the grape canopy and damage occurs later in the summer

Biology
Dark sided cutworm and its damage has been identified in Prince Edward County. It overwinters as an egg on the soil of cultivated vineyards beneath vines, stones and debris. These eggs remain dormant until the air temperatures warm during the following spring. From late May to early June, the larvae (cutworms) hatch, grow and feed. The cutworms climb up young vines to feed on foliage. Younger larvae chew small, transparent "windows" in young leaves and the older larvae are more destructive sometimes leaving only the main vein of leaf after feeding. Cutworm feeding occurs at night and during the day the larva remains curled in the soil or under stones at the base of the vine. Once the larva matures it pupates in an earthen cell near the soil surface. The grayish-brown coloured adult moths emerge in the summer and are active until fall. The female moths deposit eggs in the soil in late July and early August. Each female lays about 1000 eggs.  There is only one generation per year.

Damage is generally much lower in vineyards with mixed ground cover vegetation and where broadleaf weeds, particularly winter annual mustards such as Shepherd’s purse, are present in the vine rows in spring. Larvae are usually more common in areas with well-drained sandy or sandy-loam soils that support fewer broadleaf weeds.

Period of Activity
Late spring to early summer, approximately a 3 week period. Cutworms feed at night and are not visible during the day.

Scouting Notes
Look for damage to the foliage in young vineyards. These vineyards should be scouted regularly from bud break to shoot lengthening period, particularly after warmer nights. During the day  larvae can be found in vineyard soil beneath debris and stones and in weed clumps.  You will only see the larvae feeding on vines only if you scout at night. Significant amounts of damage can occur over a period of two or three days when the nights remain warm, and it is especially important to monitor for damaged foliage frequently during this time.

Threshold
New vines planted in untreated land previously in pasture are prone to damage, and larvae are often sheltered and somewhat confined within the protective milk cartons or sleeves placed around new vines. They should be closely inspected in spring for signs of damage and treated when necessary.

Management Notes
Do not control broadleaf weeds in spring until shoots have elongated and the first leaves have expanded.

Plant canola planted between the rows early in the spring to provide a trap crop for cutworms.

Control row middle vegetation with herbicides or repeated disking during the fall prior to the establishment of a new vineyard will help reduce damage to newly-planted vines.

Management with insecticides – Insecticides may be used to control climbing cutwom in young vineyards. See OMAFRA Publication 360, Fruit Crop Protection Guide - Chapter 4 Grapes: Recommendations for climbing cutworm control at Bud burst to first leaf.  Early-season cutworm control is most effective on small (less than 2.5 cm long) larvae. At more mature stages (>2.5 cm or 1 in. in length), they cease feeding as they prepare to pupate, and control becomes unnecessary.  Apply insecticides in the early evening, as the cutworms come to the surface to feed. Insecticides are more effective on moist soils.