Volume 62 Number 15 Date 08/10/2017
SQUASH BUG - Growers of melons, pumpkins and squash should continue to inspect plants for squash bug adults, nymphs and eggs as fruits ripen. Most crops have matured beyond the critical period of control (seedling and flowering stages), but squash bug feeding is expected to persist throughout fall, causing aesthetic damage and, in extreme cases, killing plants. Late-season control consists of disposing of cucurbit foliage and plant debris around the garden to eliminate overwintering sites and help reduce next year's squash bug population.
LATE BLIGHT - Regular monitoring of plants for signs of infection and regular treatment of fields on a five- to seven-day schedule is advised in order to prevent this disease from developing in tomato and potato crops as harvest accelerates. A second case of late blight was confirmed by the UW this week, in a commercial tomato planting in Pierce County. This case follows the season's first report on tomato in Waukesha County on July 26. All potato growing areas in the state have exceeded the threshold for late blight management and fungicidal protection of susceptible tomato and potato crops is recommended at this time.
ONION MAGGOT - Late-summer flies are emerging across southern Wisconsin. Emergence is expected to begin next week in the central areas, following the accumulation of 3,230 degree days (base 40°F). Larvae from this third and final generation will overwinter in cull onions or bulbs left behind in fields. Proper sanitation and rotating to a non-crop host are recommended for growers who experienced onion maggot problems earlier this season.
-- Krista Hamilton, DATCP Entomologist