Weather and climate conditions this week in Wisconsin
Here are this week’s take-home points about the weather. Scroll down for the full downloadable report.
Current Wisconsin weather and climate conditions
- Multiple days of precipitation impacted the state last week, bringing 2-4” for the southwest and south-central. There were pockets of 4” or more in this region as well. Totals were lower to the north (0.5”-1” common).
- An early summer heat wave brought multiple days with highs over 90°F and above-normal average temps statewide. This has helped bring GDD accumulation (since May 1) to near normal across most of WI.
Impact
- Soil moisture conditions are near normal for most of WI. Abnormal wetness is in place across the north, and there are localized areas of abnormal dryness in the south despite the rains on Monday. Wisconet research farm stations show lower topsoil moisture compared to May 1st levels as well as one year ago.
- The heavier rainfall in the south led to a reduction in D1 drought coverage, with just over 2.5% coverage in WI now.
- Corn and soybean emergence are nearing completion, with development running at a pace near to the 5-year normal for both crops. Crop condition for corn, soybeans, and wheat improved from last week, with localized reports of soybeans blooming (Source: NASS).
Outlook for Wisconsin weather and climate
- A flood watch is in place for another round of substantial rain in the SW counties on 6/27, with more rain forecasted through Sunday.
- Early July climate probabilities are showing a lean towards near-normal temperatures and above-normal precip statewide. Be aware of a moderate to major level of heat risk heading into the weekend.
- 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.
- Crop growth rebounded this week with warm temperatures and a gain of GDD this past weekend.
- 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.
- Scout for tar spot as it has been reported in 5 states close to Wisconsin.
- Forage Management
- Alfalfa stands are at or nearing second harvest in Southern Wisconsin. Scout for potato leafhopper.
- 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 increasing across the northern part of state. Consider spraying fungicide, especially to susceptible varieties if your wheat has yet to reach Feekes 10.5.1. Scab alerts and risk forecast can be found here.
- Specialty crops- Fruit
- Apples
- 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.
- Grapes
- 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).
- Berries
- 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.
- Strawberry growers have reported signs of spittlebugs, which typically cause little damage unless large populations are present (~1/plant).
- Apples
- Specialty Crops- Vegetables
- Pests
- Squash vine borer is now in southern WI and will move into central and northern portions of the state 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 across most of the state.
- 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.
- Potato leafhopper, a pest of snap beans and potatoes, continue to increase in population size.
- Diseases
- The recent hot and wet weather are prime conditions for many diseases to develop:
- Black rot of brassicas prefers temps over 77°F and high humidity. The bacteria is easily spread by water and enters the leave either through natural openings along the leaf edge or through injuries caused by insects or equipment.
- Early detection of alternaria leaf blight of cucurbits will help you control this disease before major damage occurs. Symptoms start as small, water-soaked lesions that can develop concentric rings. The fungus can survive on plant debris for up to two years so be sure to remove and destroy any infected plant tissue at the end of the season.
- Alternaria leaf blight can sometimes be confused with anthracnose and angular leaf spot which thrive in similar conditions. Angular leaf spot can be distinguished by angular lesions often confined by veins and the whitish liquid that forms on the underside of leaves when wet and forms a crust when dry. The most distinguishing symptom of Anthracnose is the dark, sunken lesions on fruit that have salmon-colored spores under damp conditions.
- Early blight risk is high in southern and central WI and moderate in the north. Early blight infects tomatoes, potatoes, eggplants, and peppers. Prevention is key and includes limiting periods of leaf wetness (when possible!) and increasing air flow through pruning.
- Downy mildew spores were detected in air samples in 5 counties in Michigan and SE Michigan has a confirmed case on cucumbers. 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.
- 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.
- Pests
If you would like to obtain a PowerPoint copy of this report, please email rue.genger@wisc.edu.
