Beginner

Scientific Name
Leptinotarsa decemlineata

Identification

• Adults are orange with 10 black stripes on the wings
• Larvae are red-to-orange with two rows of black spots along their sides
• The adult and larval stages feed on the foliage, chewing irregular holes on leaves or occasionally stems
• Feeding on the fruit surface may also occur
• High populations can completely defoliate plants

Often Confused With
N/A

Period of Activity
Feeding damage is mainly a concern early in the season when plants are small.

Scouting Notes
Examine entire plants.  Count the number of adults and larvae.  Estimate defoliation.

Thresholds
0.5 adults or larvae per plant in the first 2 weeks after transplanting or 1 adult or larvae per plant later in the season.

Advanced

Scientific Name
Leptinotarsa decemlineata

Identification
Adults are orange with 10 black stripes on the wings.  Larvae are red-to-orange with two rows of black spots along their sides.  The eggs are orange and are laid on the underside of the leaf.

The adult and larval stages feed on the foliage, chewing irregular holes on leaves or occasionally stems.  They may also feed on green fruit.  High populations can completely defoliate plants.  Young transplants are especially susceptible to defoliation. 

Often Confused With
N/A

Biology
There are 2 to 3 generations per season.

Period of Activity
Feeding damage is mainly a concern early in the season when plants are small.

Scouting Notes
Examine entire plants.  Count the number of adults and larvae.  Estimate defoliation.

Thresholds
0.5 adults or larvae per plant in the first 2 weeks after transplanting or 1 adult or larvae per plant later in the season.

Management Notes

• Rotate crops and avoid planting tomatoes adjacent to beetle overwintering sites (previous year’s tomato, eggplant or potato field).
• Chemical controls are most effective when applied to small larvae.
• A number of insecticides are available but the beetle is resistant to several of them.  This is a particular problem in areas with large acreages of both tomatoes and potatoes. 
• Trap cropping can help to reduce pesticide use.  Plant strips of potatoes or eggplant, which the insects prefer, at the edges of tomato fields to trap adult beetles.  When the beetles are concentrated on the trap crops, apply insecticides to them.  The results are fewer sprays on a more concentrated area.