A little Weed Seed Prevention can go a LONG WAY

Author: Carri Jagger OSU Extension – Morrow County

Do you fight weeds on your produce farm or in your gardens? You’re not alone! Every year weeds pop up in our production systems and some struggle to keep them under control. There are several pre and post emergent herbicide options on the market, but that’s not what I’m covering today. I’m going to look at some common weeds in production systems and the number of seeds one plant produces. When we start to think about the number of seeds that weeds produce, we soon realize why they are such a problem to control!

Redroot pig weeds produce 13,000 – 35,000 seeds per plant and it takes 3 years for the seed bank to be reduced by 50% and about 20 years to deplete the seed bank by 99%.

Howard F. Schwartz, Colorado State University, Bugwood.org

 

Giant ragweeds produce 10,300 seeds per plant and it takes 2 years to deplete the seed bank by 99%.

Theodore Webster, USDA Agricultural Research Service, Bugwood.org

 

Common ragweeds produce 3,500 seeds per plant and it takes 1 year to deplete the seed bank by 50% and 10 years for 99% depletion.

Theodore Webster, USDA Agricultural Research Service, Bugwood.org

 

Velvet Leaf produces 2,000 – 9,000 seeds per plant. Each plant produces about 70 – 200 seed capsules per plant and each capsule contains 35 -45 seeds. It takes 2 years for the seed bank  to be reduced by 50% and about 16 years to deplete it by 99% unless it is buried deep in the soil from plowing and it will persist longer.

Jan Samanek, Phytosanitary Administration, Bugwood.org

 

Common Lambsquarters produces between 30,000 – 176,000 seeds per plant and takes 12 years for 50% depletion and  78 years for 99% depletion.

Robert Vidéki, Doronicum Kft., Bugwood.org

 

Giant Foxtail produces 500 – 2,500 seeds per plant and takes 5 years for the seed bank to be reduced by 50% and 30 to deplete it by 99%.

John D. Byrd, Mississippi State University, Bugwood.org

 

Canada Thistle will produce between 1,500 and 5,300 seeds per plant and research shows low to moderate persistence – when buried 1 to 3-inches in the soil 45 to 60% of seed germinates the first year and less than 1% survives after 3 to 5 years. When buried at greater depths (7-inches or more) and left undisturbed seeds have been found to be viable for up to 30 years. 

Rob Routledge, Sault College, Bugwood.org

 

Hairy Galinsoga can produce up to 7,500 seeds and can remain viable for more than 2 years.

Robert Vidéki, Doronicum Kft., Bugwood.org

Next time you see a weed getting ready to spread it’s seeds think about these numbers and cut it down before it can spread it’s offspring all over your field. If you are experiencing issues with weeds that I didn’t mention drop me a line to share what your problem weeds might be.

 

Sources: Michigan State Department of Soil and Microbial Sciences, Weeds

https://www.canr.msu.edu/weeds/extension/michigan-s-worst-weeds

https://blogs.cornell.edu/enychp/vegetables/weed-of-the-week-hairy-galinsoga/

First Report: Downy Mildew of Cucurbits in Ohio

Downy Mildew of Cucurbits in Ohio
Date: July 15, 2025
Location: Homerville, Medina County, Ohio

Ohio counties with Downy mildew confirmed

Samples provided by the OSU Extension were submitted to the OSU Diagnostic Clinic, where microscopic examination confirmed downy mildew caused by Pseudoperonospora cubensis in a 4-acre cucurbit planting near Homerville. Approximately 10 percent of plants exhibit angular chlorotic lesions with characteristic purple-gray sporulation on the undersides of leaves, and on symptomatic plants disease severity averages 2 percent of total leaf area.

Downy mildew in cucumber.

Downy mildew in cucumber. Small, pale yellow lesions, often confined by the leaf’s veins, so that each spot takes on an angular shape. Image credit Frank Becker

underside of a cucurbit leaf—most likely cucumber—covered in tiny beads of dew. Along the veins you can see angular, brownish to grayish patches where the tissue has died, and within those patches a fine, dark-gray to purplish fuzz is just beginning to develop. That fuzzy growth is the sporulation of the downy mildew pathogen, emerging from the necrotic spots. The overall scene—water droplets on the cell-textured surface, contrasting with the darkened, angular lesions—is textbook for early downy mildew infection on cucurbits.

underside of a cucurbit leaf—most likely cucumber—covered in tiny beads of dew. Along the veins you can see angular, brownish to grayish patches where the tissue has died, and within those patches a fine, dark-gray to purplish fuzz is just beginning to develop. That fuzzy growth is the sporulation of the downy mildew pathogen, emerging from the necrotic spots. The overall scene—water droplets on the cell-textured surface, contrasting with the darkened, angular lesions—is textbook for early downy mildew infection on cucurbits.

Downy mildew in cucumber. Underside of a cucumber leaf. Along the veins you can see angular, brownish to grayish patches where the tissue has died, and within those patches a fine, dark-gray to purplish fuzz is just beginning to develop. That fuzzy growth is the sporulation of the downy mildew pathogen, emerging from the necrotic spots. Image credit Frank Becker

Confirmation in the Diagnostic Clinic. Characteristic sporangia and sporangiophore structures of a downy-mildew pathogen (in this case, Pseudoperonospora cubensis on cucumber). Scattered across the field are dozens of ovoid to ellipsoid sporangia, each roughly 20–30 µm long, with smooth, thin walls and a pale greenish tint. Image credit Francesca Rotondo

Recent climatic conditions, including frequent overnight leaf wetness from dew, daytime temperatures in the mid-70s Fahrenheit, and intermittent rainfall, have created an ideal environment for pathogen development. Although current incidence and severity remain relatively low, the pathogen’s rapid disease progression under these conditions poses a significant threat to yield if left unmanaged.

Immediate management began on July 15 with a protectant fungicide spray program targeting oomycete pathogens and subsequent applications planned at weekly intervals. Canopy thinning was performed to improve air circulation and reduce leaf wetness. Fields will be scouted every three to five days to assess treatment efficacy and adjust application timing. Severely affected foliage will be removed and destroyed to limit inoculum, and equipment sanitation protocols have been reinforced to prevent spread to adjacent fields.

Recommended active ingredients include chlorothalonil, mancozeb, cyazofamid (Ranman), the ametoctradin + dimethomorph combination (Zampro), and oxathiapiprolin (Orondis Opti). To reduce the likelihood of resistance, these fungicides should be rotated based on their modes of action. Moreover, preventive applications made before pathogen establishment are essential for the most effective disease control.

Submit your sample

Field diagnosis alone can be misleading. Many foliar symptoms overlap, and mixed infections are common. Accurate identification requires observation of the pathogen’s microscopic structures (conidia, sporangia, bacterial streaming, or hyphal morphology) under a compound microscope.

Please consider submitting fresh or well-preserved samples to the Plant and Pest Diagnostic Clinic. Our team will:

  • Macerate tissue and plate it on selective media
  • Examine spores, conidia or bacterial cells under the microscope
  • Run confirmatory tests when necessary

This process ensures that your management decisions, fungicide choice, cultural controls, resistant varieties, are based on precise diagnosis rather than assumption.

How to Submit:

  1. Complete the online Plant Diagnostic Form:
    https://ppdc.osu.edu/forms/plant-diagnostic-form
  2. Ship or deliver your samples according to the instructions on the form. Samples may be mailed:
    C. Wayne Ellett Plant and Pest Plant Diagnostic Clinic
    Ohio State CFAES Wooster Campus
    c/o Dr. Francesca Rotondo
    234 Selby Hall, 1680 Madison Ave., Wooster, OH 44691
  3. Samples may be hand-delivered:
    Requires coordination with Dr. Rotondo: (330-263-3721) | rotondo.11@osu.edu

Selling Home Produced Foods that Use Fresh Fruit: Know the Laws

Selling Home-Produced Foods that Use Fresh Fruit: Know the Laws

Cultivating Connections Conference for Farm Transition Planners

Cultivating Connections Conference for farm transition planners coming August 4 & 5

FREE FARM PESTICIDE DISPOSAL COLLECTION EVENTS AVAILABLE IN FULTON, LAKE, AND GREENE COUNTIES July152025

The Ohio Department of Agriculture(ODA) will be sponsoring three collection events for farmers to dispose of unwanted pesticides. This year, the collections are available in Fulton, Lake, and Greene counties on the following days and locations:
August 13 – Fulton County Extension, 8770 State Route 108, Wauseon, Ohio 43567, 9 a.m.–3 p.m.
August 14 – Perry Coal and Feed (Lake County), 4204 Main Street, Perry, Ohio 44081, 9 a.m.–3 p.m.
August 27 – Greene County Fairgrounds, 100 Fairground Road, Xenia, Ohio 45385. 9 a.m.–3 p.m.

The pesticide collection and disposal services are free of charge, but only farm chemicals will be accepted. Paint, antifreeze, solvents, and household or non-farm pesticides will not be accepted.

ODA sponsors the pesticide collections in conjunction with the U.S. Environmental Protection Agency. To pre-register or for more information, contact the Ohio Department of Agriculture at (614) 728-6987.

National Farmers Market Week Kickoff

Thursday, July 31, 2025
Pearl Market
N Pearl Street and E Gay Street
Columbus, Ohio 43215

Time: 11 a.m.

Come join us for a kickoff celebration for National Farmers Market Week at Pearl Market in Columbus beginning at 11 a.m. on July 31. This year’s theme is Rooted in Community. National Farmers Market Week is August 3-9, 2025.

Agenda:

11:00 – 11:03 a.m. – Welcome to Pearl Market

11:03 – 11:05 a.m. – National Farmers Market Week Proclamation

11:05 – 11:08 a.m. – Ohio Farmers Market Network – How you can participate in NFMW celebrations at your local farmers market.

QUESTIONS: Christie Welch (welch.183@osu.edu)

 

Cucurbit Disease Update: No Downy Mildew Yet but Powdery Mildew, Bacterial Wilt, Angular Leaf Spot, and Alternaria Leaf Spot Present – July 11, 2025

As of July 11, 2025, our sentinel plots and grower reports have yielded no confirmed cases of Downy Mildew on cucurbits in Ohio. Instead, we are observing several other foliar and vascular diseases that can be easily confused in the field:

1. Powdery Mildew
Powdery Mildew typically appears as white, flour-like patches on leaves and stems. Under humid conditions, it can spread rapidly and reduce photosynthetic capacity. Although its symptoms are fairly distinctive, severe infections or mixed diseases can obscure diagnosis.

Figure 3. Advanced symptoms of powdery mildew on Zucchini leaf. Image Credit: Andres Sanabria-Velazquez

Figure 1. Advanced symptoms of powdery mildew on Zucchini leaf. Image Credit: Andres Sanabria-Velazquez

2. Bacterial Wilt

We have detected Bacterial Wilt caused by Erwinia tracheiphila in melon and squash. Infected vines wilt suddenly and irreversibly during the heat of the day. Because early symptoms—such as yellowing of lower leaves—can mimic other wilts, laboratory confirmation is essential. Cucumber beetles transmit the bacteria; therefore, as their populations increase, the incidence of the disease will be higher.

Bacterial Wilt caused by Erwinia tracheiphila

Figure 2. Bacterial Wilt caused by Erwinia tracheiphila. Image Credit: Andres Sanabria-Velazquez

3. Cucurbit Angular Leaf Spot
Identified on cucumber and watermelon, Angular Leaf Spot produces water-soaked lesions that become angular when bounded by major veins. Lesions often exude bacterial ooze in high humidity, but when dry they can be mistaken for other spots.

 

Angular Leaf Spot produces water-soaked lesions

Figure 3. Angular Leaf Spot. Image Credit: Andres Sanabria-Velazquez

4. Alternaria Leaf Spot

  1. Alternaria spp. produce small, brown to black circular to irregular lesions with concentric rings on melon and squash. In heavy infections, leaves may coalesce and blight, reducing yield and fruit quality.

Alternaria Leaf Spot

Figure 4. Alternaria Leaf Spot. Image Credit: Andres Sanabria-Velazquez

Why Submit Samples?

Field diagnosis alone can be misleading. Many foliar symptoms overlap, and mixed infections are common. Accurate identification requires observation of the pathogen’s microscopic structures (conidia, sporangia, bacterial streaming, or hyphal morphology) under a compound microscope.

Please consider submitting fresh or well-preserved samples to the Plant and Pest Diagnostic Clinic. Our team will:

  • Macerate tissue and plate it on selective media
  • Examine spores, conidia or bacterial cells under the microscope
  • Run confirmatory tests when necessary

This process ensures that your management decisions, fungicide choice, cultural controls, resistant varieties, are based on precise diagnosis rather than assumption.

How to Submit:

  1. Complete the online Plant Diagnostic Form:
    https://ppdc.osu.edu/forms/plant-diagnostic-form
  2. Ship or deliver your samples according to the instructions on the form.Samples may be mailed:
    C. Wayne Ellett Plant and Pest Plant Diagnostic Clinic
    Ohio State CFAES Wooster Campus
    c/o Dr. Francesca Rotondo
    234 Selby Hall, 1680 Madison Ave., Wooster, OH 44691Samples may be hand-delivered:
    Requires coordination with Dr. Rotondo: (330-263-3721) | rotondo.11@osu.edu

New Sprayer Technologies and Best Practices for Vineyards and Orchards

This workshop will feature presentations on best spraying practices using conventional sprayers and new sprayer technology, including spray drones and Intelligent sprayer units. The afternoon will provide field demonstrations showing adjustments to improve the effectiveness of conventional sprayers, as well as sprayer operation and calibration demonstrations. OSU, MSU, and PSU Extension Specialists and the USDA-ARS Application Technology Research Unit are developing this workshop. Registration is required. Please see the agenda for program details. Lunch and workshop materials are included with registration.

DATE: August 12, 2025

TIME: 9:00 a.m.-5:00 p.m.

LOCATION: Quarry Hill Winery & Orchard, 8403 Mason Rd #2, Berlin Heights, OH 44814

REGISTRATION COST (includes lunch and refreshments): Early Registration: $45 per person until July 1; Late Registration: $60 per person, July 2 until August 1

REGISTER at GO.OSU.EDU/SPRAY2025

FLYER

This workshop provides you with the opportunity to learn best spraying practices using conventional sprayers as well as the new technology available to growers to make the pesticide application more precise and cost-effective. For example, you will see an “intelligent sprayer” with AI application (developed here in Ohio several years ago) that detects the existence of targets to be sprayed and varies the application rate on the go depending on the canopy characteristics (size, canopy leaf density).  Another new technology gaining popularity is using drones to spray pesticides. These new technologies, as well as several types of conventional orchard/vineyard sprayers, will be demonstrated in the afternoon part of the workshop. There will be plenty of time to talk with the presenters of talks, as well as with the vendors who will bring their sprayers to the site for demonstrations.

The morning part of the workshop will be indoors with limited seating capacity. Registration will be closed once the seating capacity is reached, so please consider registering early.

Ohio State University Extension Specialty Crop Team Newsletter

Editors- Thomas Becker, Agriculture and Natural Resources Educator, Lorain County and Frank Becker, Agriculture and Natural Resources Educator, Wayne County. Contributions made from team members around the state of Ohio. 

Warm and wet conditions across much of the state have continued to drive pest and disease activity in both fruit and vegetable crops. As we hit peak summer production, timely scouting and integrated pest management remain your best tools for maintaining crop health and quality.

Fruit Crops:
Spotted Wing Drosophila (SWD) remains a top concern for small fruit growers. This invasive fruit fly lays eggs inside ripening berries, with larvae feeding internally—causing soft fruit, collapse, and post-harvest losses.

To manage SWD, growers should monitor fields using baited traps placed within the fruiting zone. Traps should be checked regularly, ideally weekly, to assess fly presence. It’s important to harvest fruit frequently and remove any overripe or dropped berries to reduce egg-laying sites. At the first signs of fruit color change, apply protectant insecticides, rotating among different chemical classes such as spinosyns, pyrethroids, and organophosphates to delay resistance development. Post-harvest, rapid cooling of fruit and maintaining cold chain storage can significantly slow larval development and help protect product quality.

Sun Scald was reported in brambles following the extreme heat conditions. White or pale drupelets may appear on raspberry fruit due to intense sun exposure, a condition known as sun scald. While this disorder affects visual quality and salability, it has limited impact on flavor or nutritional value. To minimize sun scald, growers should maintain a healthy canopy by using proper pruning techniques that allow leaves to shield developing fruit. In extreme heat, consider deploying shade cloth or temporary row covers. Consistent irrigation is also critical to reduce plant stress and support recovery from heat damage.

Other pests in small fruit & orchards being reported are leafhoppers, aphids—including woolly apple, green, and rosy aphids—and spider mites (such as two-spotted and European red). These pests are showing up in scouting reports across the state. These pests often thrive during hot, dry spells and can cause significant foliage and fruit damage if left unchecked.

Regular field scouting is essential, especially on the undersides of leaves where many of these pests feed and reproduce. Growers should look for signs like stippling, curling, or honeydew. Maintaining beneficial insect populations such as lady beetles, lacewings, and predatory mites can provide natural pest control. Cultural practices such as avoiding excessive nitrogen applications can reduce lush growth that attracts pests. If pest thresholds are exceeded, selective insecticides or miticides may be used, always rotating products to reduce the risk of resistance.

Vegetable Crops
Phytophthora Root Rot has already been reported in several areas of the state, following some extremely saturated field conditions and heavy rain fall events. Persistently saturated soils have created ideal conditions for root rot diseases, particularly Phytophthora, which affects crops like peppers and cucurbits. This disease thrives in poorly drained soils and can quickly devastate fields if unmanaged. To reduce risk, improve field drainage by planting on raised beds or using plasticulture systems that shed excess water. Where appropriate, choose resistant or tolerant cultivars. Preventive fungicide applications can help protect plants during periods of prolonged soil saturation.

Powdery mildew has been confirmed in several squash plantings. Early symptoms include white, powdery patches on upper leaf surfaces and stems, which can reduce photosynthetic capacity and fruit yield. Management begins with early detection and protectant fungicide sprays.  Ensuring adequate airflow by properly spacing plants and minimizing leaf wetness also helps suppress disease development. After harvest, remove infected plant debris to reduce inoculum for future crops.

Squash bugs, stink bugs, and tarnished plant bugs have been observed feeding on vegetable crops statewide. These insects damage plants by piercing and sucking, which can lead to fruit deformities, discoloration, or aborted development.

For effective management, monitor plants closely for egg masses and early nymph stages, particularly on the undersides of leaves. When practical, remove egg masses by hand and destroy them. Cultural practices like eliminating crop debris and rotating host crops each season will reduce overwintering populations. Insecticide applications are most effective against young nymphs, as adults are often more difficult to control.

Cucumber beetles and Colorado potato beetles remain highly active and continue to pose serious challenges in cucurbit and solanaceous crops. Regular scouting is critical. Consider using sticky traps or direct plant inspections to detect rising populations early. Chemical options should be applied according to threshold guidelines, rotating among different IRAC classes to delay resistance development—especially important in managing Colorado potato beetle, which has a history of rapid resistance buildup.

In sweet corn fields, damage from European corn borer (ECB) has been reported. Monitoring ECB with pheromone traps can help time insecticide applications precisely. Applications are most effective when timed just after egg hatch, before larvae have a chance to bore into stalks and ears where they are protected from contact sprays. For growers planting sweet corn regularly, Bt hybrids are an effective tool for reducing ECB damage.

-Current Disease Update for Ohio Vegetable Growers – 7/3/2025

As of today, no downy mildew has been detected in Ohio sentinel plots, according to the most recent update from 7/3/2025. These sentinel plots, designed for early crop disease detection, are located at:

Fremont (North Central Agricultural Research Station, Sandusky County)

Huron (Huron County)

Wooster (Wayne County)

Pike County (Piketon Research Station)

Sentinel plots locations

Figure 1. Cucurbit sentinel plot locations. Image Credit: Andres Sanabria-Velazquez

Weekly scouting and spore-trap monitoring are ongoing at all four locations. Despite favorable conditions and outbreaks in neighboring states, these Ohio plots remain negative so far for Pseudoperonospora cubensis activity.

 

Figure 2. Field visit to a cucurbit sentinel plot in Ohio for early detection of downy mildew and other vegetable diseases. From left to right: research team members conducting disease scouting and environmental monitoring.

Figure 2. Field visit to a cucurbit sentinel plot in Piketon, Ohio, for early detection of downy mildew and other vegetable diseases. From left to right: research team members conducting disease scouting and environmental monitoring. Image Credit: Andres Sanabria-Velazquez

However, powdery mildew has been observed in cucurbit crops across the state, and Phytophthora capsici has been confirmed in pepper plantings. Growers should maintain regular scouting and utilize pathogen-free seed, proper irrigation, and effective fungicide rotations as needed.

Figure 3. Early symptoms of powdery mildew on a cucurbit leaf. Image Credit: Francesca Rotondo

Figure 3. Early symptoms of powdery mildew on a cucurbit leaf. Image Credit: Francesca Rotondo

 

Figure 3. Advanced symptoms of powdery mildew on Zucchini leaf. Image Credit: Andres Sanabria-Velazquez

Figure 4. Advanced symptoms of powdery mildew on Zucchini leaf. Image Credit: Andres Sanabria-Velazquez

Figure 6. Microscopic view showing characteristic structures of powdery mildew

Figure 6. Microscopic view showing characteristic structures of powdery mildew. Image Credit: Francesca Rotondo

Figure 5. Typical symptoms of Phytophthora blight caused by Phytophthora capsici on pepper stem tissue. Image Credit: Francesca Rotondo

Figure 5. Typical symptoms of Phytophthora blight caused by Phytophthora capsici on pepper stem tissue. Image Credit: Francesca Rotondo

Diagnostic Confirmation: Submit suspect samples to the OSU Plant and Pest Diagnostic Clinic, directed by Dr. Francesca Rotondo. Early confirmation allows for timely interventions (https://ppdc.osu.edu/).

Samples may be mailed:
C. Wayne Ellett Plant and Pest Plant Diagnostic Clinic
Ohio State CFAES Wooster Campus
c/o Dr. Francesca Rotondo
234 Selby Hall, 1680 Madison Ave., Wooster, OH 44691

Samples may be hand-delivered:
Requires coordination with Dr. Rotondo: (330-263-3721) | rotondo.11@osu.edu