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Looking Ahead
Volume 61 Number 17 Date 08/25/2016 CORN EARWORM - Substantial flights continued in the southern and central areas of the state. The late-season migration accelerated this week and has to date yielded a cumulative total of 3,507 moths at 17 sites. Counts at the Columbia and Fond du Lac County monitoring sites were particularly high and ranged from 890-1,095 moths per trap. The latest activity signals that the threat to fresh market sweet corn plantings has intensified and egg laying will persist into September. WESTERN BEAN CUTWORM - Corn surveyed in the central counties was 2-60% infested with 1-2 larvae per ear. The cutworms were mostly in the late instars and should enter the pre-pupal overwintering stage by September. This week's observations suggest that the increased pheromone trap counts documented in July were an accurate predictor of higher larval pressure in the field since infestations are somewhat common, especially in Chippewa, Dunn, Eau Claire, Green Lake, Juneau and Marquette counties. Western bean cutworm larvae have been found in about 15% of the 229 cornfields sampled this month. CORN ROOTWORM - The annual beetle survey is complete. Contrary to earlier forecasts, review of the field data indicates that populations are lower than last year across southern, central and east-central Wisconsin. Beetle counts in the west-central and northern counties are markedly higher. Results of the survey are summarized in the CORN section. LATE BLIGHT - Fresh market tomato producers and home gardeners are advised to continue monitoring plants for signs of infection now that late blight spores are in the state. Development of this disease has been confirmed by the UW on tomato in Dane County and on potato and tomato in Polk County. Plants showing symptoms of late blight cannot be saved and should be disposed of in plastic bags to limit spread to other plants. Symptomatic plants may be submitted for free testing to the UW Plant Disease Diagnostic Clinic:https://pddc.wisc.edu/sample-collection-and-submission/. LILY LEAF BEETLE - This newly-established invasive beetle was reported earlier this month by a resident of Plover in Portage County, marking the southernmost detection of lily leaf beetle in the state. The northernmost record of the beetle is from Merrill in Lincoln County. Lily leaf beetle was first discovered in Wisconsin in 2014 and reproducing populations currently exist in portions of in Lincoln, Marathon and Portage counties. -- Krista Hamilton, DATCP Entomologist 
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