[8/23/2016] Unlike the past 2 years, where late-season Corn Earworm (CEW) immigration events have been late to less frequent, we have experienced several significant incoming flights this summer. Moreover, because the southern states that provide our source moths are reporting record high numbers in all key crops (sorghum, cotton, corn), the numbers we are seeing at most of our southern MN locations are above average to high.
[8/10/2016] As with last week's catch at Rosemount and Blue Earth, Corn Earworm moth catch continues to increase at these locations. At Blue Earth, trap catch went up to 185 on 8/4 and 198 on 8/5. Also, noted in the Blue Earth graph, the flight this year is much higher than the past two years (essentially back to a more "normal" flight); this increase is not surprising given the recent Low pressure system that moved through the state. In brief, the Lows typically bring warm/humid air from southern states northward. As these fronts converge with a High pressure front, this typically results in a rainfall event, and facilitates both the movement (migration) of insects northward, and their deposition wherever these fronts converge; thus can be spotty depending on how the fronts converge, and over which states, etc.
[8/4/2016] Given recent trends in recent trap catches of CEW moths in pheromone traps, sweet corn now silking (early, peak and early brown silk) may be at risk to egg-lay, and should be scouted, and/or traps checked more frequently this week.
[7/26/2016] The first significant flights of corn earworm (CEW) moths have been detected this past week at several southern MN locations, including Sleepy Eye and at our Agric. Expt. Station, Rosemount, MN. Although moth counts are still low (<10 moths/night), Blue Earth has reported two significant catches, and traps should now be deployed if not already out, and moth catch should be monitored closely.
[7/20/2016] SWD numbers again increased this past week, at most locations, with many locations exceeding 100/trap/week, and in Forest Lake, reaching 500/week. This not only included commercial berry farms, but also increases at some of the nature preserve, state/county parks (>100/week); SWD trap catch in parks likely reflects this fruit fly’s attraction to many wild host plants, such as honeysuckle early in the season, and possibly wild grapes, blackberries and raspberries, becoming more dominant in July-August.
[6/22/2016] As noted last year, the early SWD activity (and our high trap catch) has been observed where active fruiting, preferred soft-skinned berry crops occur. This is even more critical this year, as the first SWD adults arrived 10-14 days earlier (caught between June 6-13th), compared to the previous 3 years. This week, it is therefore not surprising to see the highest numbers in June-bearing strawberry, and Summer-bearing raspberry. Also, the majority of adults to date are females, with the risk of egg-lay immediate.
To minimize the risk of SWD infested berries at harvest, you need to be planning and implementing your management plan -- all season. For many crops (blueberry, summer and fall raspberry) it’s not too late to get started, but TIMING is Everything with this pest. All small fruit growers (conventional and organic) should review the following resources, to manage this invasive pest, and continue to prepare for the season ahead.
[6/15/2016] The first SWD adults, collected in apple cider vinegar (ACV) traps, were confirmed Monday, June 13th, at several locations in the 7 county metro. Since we check traps weekly, these SWD could have arrived anytime between June 6-13th. This catch is about 2 weeks earlier than SWD has been detected the past 3 summers. SWD have been verified from trap collections near Waverly (2 females), Rosemount Agric. Research Station (1male, 1 female), Northfield (4 females) and Forest Lake, MN (1 female). Thus far, traps that have been positive for SWD have been placed near June bearing strawberries, summer and fall bearing raspberries and blueberry fields.