Click to enlarge.

Beginner

ALSO CALLED “CLIMBING” CUTWORMS

Scientific Name
Peridroma saucia + Feltia jaculifera

Identification

• Larvae are soft and fat, and roll up when disturbed
• The variegated cutworm is larger than the other cutworm species
• Produces scattered leaf feeding, particularly along leaf edges
• Fruit damage ranges from light surface feeding to deep holes
• Damaged fruit may be invaded by secondary micro-organisms, causing rot

Often Confused With
N/A

Period of Activity
Moth catches begin in July.  The worms feed mostly at night.  During the day they may be found curled up in the damaged fruit or in the soil around the plant.  Under heavy foliage, they may be found on the plant during the day.

Scouting Notes
Adults can be monitored using black-light traps or pheromone traps, starting early in the season.  Once moths are present, field scouting can determine the level of infestation.  Early morning or evening, when temperatures are cooler, are good times to scout for these pests.

Thresholds
1 larva per 30 plants (scouting).
7 moths per trap per week (in delta or wing style pheromone traps).

 

 

Images by

Jack Foreman, All Rights Reserved.

 

Advanced

ALSO CALLED “CLIMBING” CUTWORMS

Scientific Name
Peridroma saucia + Feltia jaculifera

Identification
Larvae are soft and fat, and roll up when disturbed.  The variegated cutworm (VCW) appears later in the season and is larger than the other cutworm species.  They produce scattered leaf feeding, particularly along leaf edges.  Fruit damage ranges from light surface feeding to deep holes.  Damaged fruit may be invaded by secondary micro-organisms.

Often Confused With
N/A

Biology
Although VCW can survive the winter in our growing area, a large proportion of the variegated cutworm population is thought to migrate into Ontario each season.  Cutworms have one to four generations per year depending upon the species and location.

Period of Activity
Moth catches begin in July.  The worms feed mostly at night.  During the day they may be found curled up in the damaged fruit or in the soil around the plant.  Under heavy foliage, they may be found on the plant during the day.

Scouting Notes
Adults can be monitored using black-light traps or pheromone traps, starting early in the season.  Once moths are present, field scouting can determine the level of infestation.  Early morning or evening, when temperatures are cooler, are good times to scout for these pests.

Several types of traps can be used with pheromone lures for VCW, including bucket-style Multipher or Uni traps (with insecticide strips) and delta or wing traps (with sticky trays).  These traps are used with a VCW pheromone lure to attract the moths.

Traps should be hung from stakes in the tomato field, at a height of 1 ¼- 1 ½ m (4- 5 ft.).  Space traps at least 90 m (300 ft. or 100 yards) apart and away from trees or obstructions which would interfere with the plume of pheromone that will extend downwind of the trap.  It is this pheromone plume that the male moths will follow to find the trap (because they think they are going to find a female moth).  Each type of trap has a place for the pheromone lure to be attached.  For bucket-style traps, an insecticidal (DDVP) strip should be placed in the trap to kill the moths that enter.  Otherwise, some may escape.  With delta or wing traps, moths are trapped on the sticky surface.

Aim to have traps installed by late June or early July and monitor them regularly (at least 1- 2 times/wk).  Ideally, monitor them at exact intervals (eg. every 3 days) to get the most accurate indication of changes in pest numbers.  Count and record the number of moths captured.  For bucket traps, remove the insects and dispose of them away from the field.  Sticky traps (or removable sticky trays) will need to be replaced as needed, when too much dirt, debris, and insects accumulate.

Pheromone lures should be replaced at the intervals recommended by the supplier (usually 4- 6 weeks).  As stray pheromone can interfere with trap catches, it is best to use disposable gloves when installing and removing pheromone lures, so you don't contaminate other surfaces with pheromone.  Dispose of old lures, packaging, gloves, and captured insects away from the field.  If using other types of pheromones in your scouting program, use separate gloves and traps for each type.

Thresholds
1 larva per 30 plants (scouting).
7 moths per trap per week (delta or wing style pheromone trap).

Management Notes

• Cutworm control is most effective on small (less than 2.5 cm, 1 in.) larvae.   Larger larvae are difficult to control with insecticides.
• At more mature stages (> 2.5 cm or 1 in. in length), they cease feeding and prepare to pupate, and control becomes unnecessary.
• Apply insecticides in the early evening, as the cutworms come to the surface to feed at night.
• Insecticides are more effective on moist soils.

 

 

Images by

Jack Foreman, All Rights Reserved.