Current Wisconsin weather and climate conditions

• Precipitation was very hit-or-miss last week, with many receiving totals of 0.5″ or more where storms tracked. The 30-day precipitation totals are below average for most of the state, especially near the IL border
  • An active May 20-21 brought 2” or more for some.
• Temperatures were above normal across most of the state by 5°F or more, with high temps topping 90°F at some southern locations on Thursday.

Impact

• Soil moisture conditions showed some minor improvements from last week. However, the southern and eastern parts of the state still remain much drier than normal
  • No change in drought coverage in WI compared to last week
• Corn and soybean planting once again made big gains from last week (73% & 66% complete, respectively), with emergence well underway (Source: NASS).
  • Dry and warm conditions (prior to Thursday’s storms) allowed for rapid planting progress

Outlook for Wisconsin weather and climate

• Overnight frost/freeze risk is slim outside of the north and central. Check this link for day-to-day freeze chances from NWS Milwaukee.
• A quiet week for precipitation is on tap, with a few minor chances for rain during the middle of the week.
• As we wrap up May and head into the first days of June, temperature probabilities are a mixed bag across the state with a lean towards below normal precip.

Agronomic considerations

• Field Work and Conditions
  • Very northern areas of the state still have a frost risk this week
  • Avoid trafficking fields in moist conditions to prevent compaction and rutting with recent heavy precipitation. ​
  • In drier regions of the state, particularly southern and southwest WI, consider earlier termination of cover crops to retain soil moisture if conditions remain dry. If conditions are wet, consider delaying termination to manage excess soil moisture.
• 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. ​
  • Ensure temperatures (day, night, and soil) are conducive for herbicide applications. Pre-emergent herbicides require moisture for activation.​
  • While slug issues have not been 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 larvae have started and the window of damage is beginning. Begin scouting for signs of feeding as soon as corn plants emerge. 
• Forage Management ​ 
  • Continue scouting for alfalfa weevil as alfalfa stands grow.
  • Alfalfa stands in southern WI are rapidly growing. Watch for lodging if plants reach tall heights before first harvest. See first harvest considerations here.
  • Monitor alfalfa quality closely in the next week. Quality is expected to drop, especially with the upcoming return to warmer temperatures. Be mindful not to damage fields when harvesting if fields are still wet
• Small Grains​ 
  • Scout for stripe rust and any early signs of disease with recent cool and wet weather.
    • Fusarium Head Blight risk is low across the state but consider this reminder about spraying fungicides. Scab alerts and risk forecast can be found here.
  • Reminder to properly stage small grains such as winter wheat, as many herbicides cannot be applied after Feekes 5.
• Specialty crops- Vegetables​
  • 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.
  • Common asparagus beetle populations are at damaging levels across most of the state including the north although they are starting to decrease in southwest Wisconsin. If you have had problems before, make sure to scout the edges of those fields in the afternoon when these beetles are most active.
  • The greatest risk for seed corn maggot damage is the northeast and along Lake Michigan. Onion maggot continues to progress across the state with the greatest severity in NW, central and SE WI. Cabbage maggot severity is greatest in the south, central and northwest regions of the state. These pests overwinter in Wisconsin as pupae in the soil. When the flies emerge, they are attracted to fields with high organic matter. If possible, terminate and incorporate cover crops 2-3 weeks before planting to reduce the attractiveness of these fields as egg laying sites. Delaying direct seeding until soil is warmer will reduce the risk of seedling damage.
  • Reminder that trap crops like blue hubbard squash need to be planted at least two weeks ahead of your cash crop for cucumber beetle management. 
  • Cucurbit growers may consider a kaolin clay drench of trays before transplanting as a mechanical barrier and repellant to reduce cucumber beetle feeding.
  • Scout for black cutworm damage (feeding on leaf edges and cutting of seedlings) caused by moths brought to Wisconsin on weather fronts. Check trap catches in your region with the DATCP pest survey.
• 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 50℉ from the biofix date.​
  • Keep track of degree-days (base 50℉) 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 50℉ have accumulated from petal fall.​
  • Grape growers can begin fertilization prior to bloom and should review last year’s petiole analysis to determine nutrient needs. Check out this recent UW Fruit News article on Fertilizing Wine Grapes.

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