Current Wisconsin weather and climate conditions

• Precipitation last week across most of the state was light, mainly at half inch or less. Most of the state has been at or below 70% of normal precipitation since May 4th (30 days ago).
• Cooler-than-normal temperatures were common across the southern 2/3 of the state (2-6ᵒF below normal), with closer-to-normal conditions in the north. The past 30 days have also been cooler-than-normal in the south, with a slight lag in GDD accumulation.

Impact

• Soil moisture conditions across most of the state are near normal, as estimated by the SPoRT-LIS model. Following a week with not a lot of precip, Wisconet stations across the state have showed a decline in near-surface soil moisture since last week Tuesday.
• The area of abnormal dryness in the north, as indicated by the USDM, expanded by >10% from last week after a very dry last few weeks.
• Corn and soybean emergence continue to make sizable gains in emergence progress (69% & 57% complete, respectively), with planting nearing completion (Source: NASS).

Outlook for Wisconsin weather and climate

• ​Precipitation chances are highest in the central and north over the next week with multiple days with precipitation chances coming up.
• Mid-June climate probabilities are leaning strongly towards warmer than normal statewide. Best odds for warmer-than-normal temps are in the W/NW. This will add to the GDD total since planting and help push crop progress along.
• The month of June probabilities (updated on May 31) are showing a lean towards warmer-than-normal, with uncertainty for precip (equal chances).

Agronomic considerations

• Field Work and Conditions
  • Avoid trafficking fields in moist conditions to prevent compaction. ​
  • See these considerations for early season corn management.
  • Crop growth has been slowed with recent cooler temperatures. See how wildfire haze may impact corn growth.
  • Take stand counts to make any replant decisions. See the corn and soybean replant guides.
• 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.​
  • As corn and soybean crops emerge, 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. ​
  • Be observant of black cutworm and true armyworm moths migrating to the state. Check trap catches in your region with the DATCP Pest Survey. Sign up for insect pest alerts specific to your region. ​
    • Reports of black cutworm have started, and the window of damage has begun. Begin scouting for signs of feeding as soon as corn plants emerge. 
• Forage Management ​ 
  • Continue scouting for alfalfa weevil as alfalfa stands grow. Weevil feeding can slow regrowth.
  • Many alfalfa stands in Southern WI have been harvested. See first harvest considerations here.
  • Consider annual forage options depending on your situation and forage goals.
• Small Grains​ 
  • Scout for stripe rust and any early signs of disease with recent cool and wet weather. ​Remember that fungicides for stripe rust are also effective for FHB.
  • Fusarium Head Blight risk is low across the state but consider this reminder about spraying fungicides, especially to susceptible varieties. Scab alerts and risk forecast can be found here.
• Specialty crops- Vegetables​
  • The first generation of seed corn maggot have emerged and the second generation is in southern WI now and will start making its way to central WI next week. Mated females will begin laying eggs in southern WI in the next 5-7 days. Risk will be high in southern WI during the first week of June. Onion maggot risk is high in the north, but it is decreasing in the south. Cabbage maggot severity is high across the state. Adults are attracted to areas of high organic matter such as a recently tilled field or areas of high residue to lay eggs.
  • Start scouting for aster leafhoppers. Aster leafhoppers transmit aster yellows to a wide variety of crops including lettuce, celery, and garlic. Leafhoppers move into nearby vegetable fields when alfalfa is harvested. Not all leafhoppers carry the pathogen that causes aster yellows; however leafhoppers can migrate to WI already infected with the pathogen. 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.
  • Potato leafhopper is a pest of snap beans and potatoes that also moves into vegetable fields when alfalfa is harvested. The greatest injury occurs when plants are small.​
  • Continue scouting for Colorado potato beetle on potatoes and eggplant. Adults are now in most southern and central portions of the state with exception of the most eastern portions of these regions. Egg masses have been detected in the SW. Focus early season scouting on border rows.
  • Cover eggplant with row cover immediately after transplanting to prevent damage from Colorado potato beetle and flea beetles. Keep the plants covered until they start growing vigorously. Remember to remove when flowering.
  • Be on the lookout for purple spot in asparagus. The recent wet and cool conditions promote the release of spores from infected residue from last season.
• Specialty Crops- Fruit​
  • 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.​
  • Apple growers can reference the NEWA weather station network to monitor disease infection events for apple scab and fire blight. Make sure to keep track of green tip and petal fall dates. Check out your nearest weather station: NEWA Weather Station Network (Cornell).​
  • Codling moth have been captured in Southern WI. Make sure to check traps after warm, calm evenings to establish a biofix date. Biofix occurs when ~5 or more moths are captured in one evening or captured across consecutive nights. First generation larvae will emerge after ~250 degree-days base 50ᵒF from the biofix date.​
  • Keep track of degree-days (base 50ᵒF) from petal fall to determine the end of plum curculio movement into the orchard. Plum curculio will continue movement into the orchard until ~308 degree-days base 50ᵒF have accumulated from petal fall.​
  • Recent rain events have driven infection periods for grape diseases. Grape growers may consider reviewing grape phomopsis monitoring and management. ​
  • Grape growers can reference the NEWA weather station network to monitor disease infection events for phomopsis, powdery mildew and black rot. Check out your nearest weather station: NEWA Grape Diseases Model.​
  • Strawberry growers may consider reviewing scouting and management strategies for thrips, tarnished plant bug and mites.

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