Current Wisconsin weather and climate conditions

• Multiple days of precipitation impacted the state last week, bringing 1-3” for the north and southwest. Conversely, there were many locations that received very low totals, particularly in the east/southeast and between La Crosse & Eau Claire.
• Temperatures in the state were below normal last week except for the far south. 30-day average temperatures that were 3°F or more below normal were quite common across Wisconsin, leading to a lag in GDD accumulation since May 1.

Impact

• Soil moisture conditions improved in the north with the rainfall last week, with abnormal dryness still in place in the far south. Wisconet stations show a mixed bag in moisture gained or lost since last week, depending on how much rain was received.
• The area of abnormal dryness (D0) in the north was greatly reduced from last week, with no change in the south..
• Corn and soybean emergence are nearing completion, with development running at a pace near to the 5-year normal for both crops. However, crop condition for corn, soybeans, and wheat dropped from last week (Source: NASS).

Outlook for Wisconsin weather and climate

• The next 7 days look very active for precip. Be aware of some potentially excessive rainfall totals early next week.
• Late June climate probabilities are showing a lean towards above-normal temperatures and precip. Be aware of the risk of extreme heat over the next few days.
• The outlook for July indicates a lean towards warmer than normal with precip uncertainty (outlook updated on 6/19).

Agronomic considerations

• Field Work and Conditions
  • Avoid trafficking fields in moist conditions to prevent compaction.
  • See these considerations for early season corn management. See how wildfire haze may impact corn growth. 
  • Crop growth has been slowed with cooler temperatures.  Much of the corn crop is short due to a lack of heat units but is expected to rebound with upcoming warm temps.
  • Corn is reaching the growth stage appropriate for taking presidedress soil nitrate tests (PSNT).
• Manure Applications
  • Reminder of Wisconsin’s NR 151 Runoff Rules with the timing of manure spreading and current runoff levels. Check DATCP Runoff Risk Advisory Forecast.
• Pest Management ​ 
  • Scout fields to note which weed species are emerging and/or which species escaped herbicide application.
  • As corn and soybean crops grow, note growth stages to time future applications and sampling. ​
  • While slug issues have not been as severe this year, UW is monitoring populations weekly across the state with SlugNet. ​Slug pressure will decrease with increasing temperatures and crop maturity.
  • Check moth trap catches in your region with the DATCP Pest Survey. Sign up for insect pest alerts specific to your region.
  • Routine scouting in corn to watch for: true armyworm, stalk borer, and European corn borer.
  • Alfalfa weevil populations are coming to an end. Potato leafhopper numbers are increasing; keep an eye on populations the next several weeks.
  • Use the VDIFN model to see risk in your region for several economically important pests.
• Forage Management ​ 
  • Alfalfa stands in northern WI are still being harvested. See first harvest considerations here. Some regions are considering a second harvest.
  • Consider annual forage options depending on your situation and forage goals.
• Small Grains​ 
  • Scout for stripe rust and any signs of disease with recent cool and wet weather. Cephalosporium stripe is showing up in Wisconsin. ​
  • Fusarium Head Blight risk is low across the state but consider spraying fungicide, especially to susceptible varieties. Scab alerts and risk forecast can be found here.
• Specialty crops- Fruit​
  • Apple and grape growers can reference the NEWA weather station network to monitor for disease infection periods in their area. Check out your nearest weather station: NEWA Weather Station Network (Cornell).
  • Apple scab fruit lesions have been observed in Southern WI, likely pushed along by recent rains. Continue scouting scab susceptible varieties. A reminder that protectants will typically wash off after ~1inch of rain.
  • Apple growers should continue monitoring degree-day (base 50℉) accumulation for Codling moth. First generation larvae will emerge after ~250 degree-days (base 50℉) have accumulated from the biofix date. Second generation larvae will typically emerge at ~1250 degree-days (base 50℉) from the biofix date.
  • Apple growers should keep track of degree-day (base 50℉) accumulation from petal fall to determine the end of plum curculio movement into the orchard. Plum curculio will typically cease movement into the orchard after ~308 degree-days (base 50℉) have accumulated from the petal fall date.​
  • Recent rain events have driven infection periods for grape diseases. Check out this article that overviews signs/symptoms of phomopsis, black rot, downy mildew and powdery mildew: Grape Scouting Report, June 2021 (UW Fruit News).
  • Strawberry growers have reported signs of spittlebugs, which typically cause little damage unless large populations are present (~1/plant).
    • Wisconsin fruit growers can reference the Midwest Fruit Pest Management Guide for a list of registered products and recommended best practices. View the MFPMG Online or order a hard copy here: MFPMG Hard Copy.
• Specialty Crops- Vegetables​
  • White mold was detected in high tunnels in the past 1.5 weeks. White mold can affect a wide variety of crops including beans, potatoes, cabbage, and pepper. Information on symptoms and management can be found here.
  • Squash vine borer will be moving into southern WI over the next week. Monitor for activity of these orange and black moths. Row covers can be used to exclude adults early in the season but must be removed for flowering. If you use insecticides, the timing of treatment is key. Treatment must occur before eggs hatch and larva enter stems where they are well protected. More information on organic control methods can be found here.
  • Scout for cabbage loopers, diamondback moths, and imported cabbage worms as risk is now high in southern WI.
  • The second generation of seed corn maggot is in central and northern WI. The risk is high in central WI where mated females will begin laying eggs in the next 5-7 days. The 2nd generation poses a risk when eggs hatch and larva start feeding on newly seeded and transplanted crops. Cabbage maggot risk remains high in the north as well as along Lake Michigan.
  • Continue monitoring for aster leafhoppers. Aster leafhoppers transmit aster yellows to a wide variety of crops including carrots, lettuce, celery, garlic, and many types of flowers. The best way to control aster yellows is by controlling the leafhoppers. Once plants are infected, they will not recover and must be removed to reduce the spread of this disease. Use the aster yellows index (page 19) in the Commercial Vegetable Production guide to help determine when to spray. You can also sign up for text alerts from Michigan State University on infectivity rates from their trapping network. Reports out of Michigan indicate elevated infectivity levels so far this year.​
  • Downy mildew spores were detected in air samples in Michigan. Spores are detected a few days to a few weeks before symptoms are seen. Keep an eye on cucumbers and melons. Find management information here.
  • Continue scouting for Colorado potato beetle on potatoes and eggplant. Initial egg hatch is well underway in southern WI. Egg masses are now abundant in central WI. Colonizing adults will be impacting Antigo and Rice Lake regions in the next 3-7 days.
  • While removing garlic scapes, be on the lookout for symptoms of fusarium basal rot, botrytis neck rot, white rot, and stem and bulb nematodes. This chart from the Ontario Vegetable report can help distinguish between symptoms.
  • Potato leafhopper, a pest of snap beans and potatoes, continue to increase in population size

If you would like to obtain a PowerPoint copy of this report, please email rue.genger@wisc.edu.