Website: insectlab.russell.wisc.edu

PJ Liesch shared a diverse mix of landscape, fruit and vegetable, and structural pest activity from around Wisconsin:

Landscape & Lawn Pests

• Swarming Ants: Expect swarms of turfgrass ants (e.g., cornfield ants, Lasius spp.) during warm, sunny afternoons in late August to early September.
• Dogwood Sawfly: Significant defoliation reported; larvae often go unnoticed until they cause dramatic damage. Can mimic mammal browse.
• Elm Zigzag Sawfly: Continued damage in central and south-central Wisconsin. First found in Portage County in July 2024.

Fruit & Vegetable Pests

• Chewing Damage on Peppers, Tomatoes, Eggplants: Likely caterpillars; nighttime scouting recommended.
• Hornworms: Tomato and tobacco hornworms confirmed on peppers in Dane County.
• Broad Mites: Found on spicy peppers; caused leaf distortion resembling herbicide drift. Likely greenhouse origin.
• Yellowstriped Armyworm: High populations in hoop house tomatoes; larger larvae nearly done feeding, smaller ones treated with BTK (Bacillus thuringiensis kurstaki).
• Whiteflies & Aphids: Heavy infestations in hoop house tomatoes; sticky traps recommended for monitoring for whiteflies in combination with visual scouting.
• Japanese Beetles: Activity slowing but still present, especially on pole beans and fruit trees.
• Corn Earworm (Tomato Fruitworm): Damage reported in sweet corn and tomatoes.

Structural & Miscellaneous Insects

• Dubia Roach: Unusual indoor sighting linked to escaped feeder insects from reptile tanks.
• House Centipedes: Multiple reports; fast-moving, harmless predators.
• Pantry Pests: Indian meal moths, carpet beetles, and sawtoothed grain beetles active.
• Black Witch Moth: Rare sightings tied to hurricane season jet stream patterns.
• Foreign Grain Beetle: Expected seasonal emergence in new homes due to moist construction materials; harmless and self-resolving.

Stinging Insects

• Yellow Jackets & Bumblebees: Peak season for nest activity; increased reports.

PJ wrapped up with a reminder that he’ll be on vacation through Labor Day and will monitor email for urgent issues.