Volume 62 Number 9 Date 06/22/2017
WESTERN BEAN CUTWORM - Moths have begun appearing in pheromone traps, signaling the start of the annual flight. One was caught on June 18 near Janesville in Rock County and 14 others were collected at sites in Columbia, Dodge and Green Lake counties. Scouting corn plants for egg masses and small larvae is recommended for advanced southern and western fields in the week ahead.
EUROPEAN CORN BORER - Larvae produced by the spring moth flight are in the first and second instars, and fresh whorl feeding injury is becoming detectable in a few taller southern Wisconsin cornfields. The treatment window for first-generation corn borers has opened in the southern half of the state with the accumulation of 800 degree days (modified base 50°F).
APPLE MAGGOT - Flies are likely to begin emerging next week. Apple growers concerned about this pest are advised to set a minimum of three traps per 10 acres before the end of the month, increasing the density in July to one trap every 200-300 feet along the orchard perimeter. The traps should be hung at eye-level adjacent to wild hosts and near early-ripening cultivars.
JAPANESE BEETLE - Adults were noted to have emerged near La Crosse by June 10 and in the Beloit area on June 12. Damage to fruit trees, ornamentals, nursery stock and field crops can be expected for the next two months across most of the state, with heaviest populations potentially occurring in the western areas where the beetle's range is expanding.
CODLING MOTH - Egg hatch has peaked in most apple orchards. First-generation larvae are presently in the early to intermediate growth stages, and now is an opportune time to check fruits for entry holes and frass to assess codling moth control programs. Moth counts in pheromone traps varied widely this week from 1-47 per trap.
SPOTTED WING DROSOPHILA - Emergence of flies has been confirmed in Columbia, Dane, La Crosse and Sauk counties as of June 21. The appearance of SWD adults should be viewed as an early warning to fruit growers to increase monitoring efforts and make preparations for possible insecticidal control. Insecticide use is not advised until SWD infestation is verified by trapping or visual inspection.
CORN EARWORM - Four early moths were captured in the Arlington pheromone trap between June 15 and 19. This development indicates a migratory flight into Wisconsin has occurred, and larvae could begin infesting sweet corn and vegetables next month.
-- Krista Hamilton, DATCP Entomologist