Midwest Mechanical Weed Control Field Day Returns!

Last year this event was held in Wooster, OH and it was a great success, with over 150 farmers in attendance. This year the event has rotated to West Lafayette, IN, home of Purdue University if you care to attend. A full day of weeding tool demonstrations, trade show, and cultivation education for both vegetables and row crops will be on display.

Champaign, IL. In partnership with Purdue University, this year’s Midwest Mechanical Weed Control Field Day will take place on Wednesday, September 11 at Purdue University’s Horticulture research station. 

At the morning Expo you can see weeding tools and speak with company reps from manufacturers in the US, Europe, and Japan, and meet the farmers in attendance from all over the region. At the morning education sessions, learn from experienced farmers and university weed scientists from surrounding states. ‘Weed control on the tillage spectrum’ will make the connection between tillage and weed management – with demos and talks on tarping for vegetables and plowing down cover crops with residue management in mind. 

A walk-behind tractor exhibition – ‘Walk-Behind Alley’ – features demonstrations of walk-behind tractors and hand tools. A wide variety of cultivators, hand tools, and the paperpot transplanting system will be shown. You can also visit the trade show exhibit booths to meet other supply companies, like equipment dealers for all manner of machinery, seed, tools, fertilizers, and soils. 

At noon, the field day will break for lunch – an opportunity for farmers to meet and network, or continue looking at trade show equipment and speaking with exhibitors. In the afternoon farmers follow the tractors out to the demonstration field, where corn, beets, and brassicas have been planted especially for the demonstrations. Many 3-point, camera-guided, autonomous, and belly-mounted cultivators and cultivating tractors will be demonstrated in the field and explained by manufacturers. These demonstrations will show how the machines should be mounted and properly adjusted according to crop and soil conditions, and will help farmers visualize how the implements can work on their own farms. 

Row-crop tools in demonstration include precision-controlled tine-weeders and several types of camera-guided cultivators with finger weeders and all manner of other tooling – see all types of knives, hilling discs, etc. Demonstrations will be held in 4’’ corn. 

Vegetable weeding tools include cultivating tractors past and present, a variety of belly-mounted and rear-mounted steerable tools, and cultivators from Japan! 

Registration for this full-day of learning and networking on mechanical weed control is just $75. Registration includes lunch and all the machinery demos you can handle. It is recommended that everyone register early as each year space runs out. 

This event is perfect for farmers and ag advisors who want to: see a particular weeding tool before buying it, learn how to adjust cultivators, see what is new in cultivation, or learn from other farmers. 

Here is the general information for the event: 

When: Wednesday, September 11, 2024 

Where: Purdue University – MEIGS Horticultural Research Farm 9101 S 100 E Lafayette, IN 47909

How Much: $75 (includes lunch) 

Register online at: https://thelandconnection.regfox.com/2024-midwest-mechanical-weed-control-field-day

*Walk-in registration will be available, but lunch and conference amenities are not guaranteed.

Field Day webpage: https://www.thelandconnection.org/event/2024-mmwcfd/

For more info on the event or to register by phone, contact Crystal at crystal@thelandconnection.org or (217) 840-2128. 

Inquiries for interviews on radio, print, and beyond are welcomed – Please reach out to Sam Oschwald Tilton, glacialdrift@protonmail.com, or 414-213-5337

Interested in exhibiting your products and connecting with farmers at the field day? Please contact us

This article was written by Dr. Francesca Rotondo.

Gummy Stem Blight, caused by Didymella bryoniae, is a significant disease affecting cucurbit crops like squash, pumpkins, cucumbers, and watermelons. It can impact plants at any growth stage. The disease is also a concern for greenhouse-grown cucumbers, affecting all above-ground parts of the plant.

The pathogen can be seed-borne or survive on organic debris from previous crops. The fungus spreads through two types of spores—ascospores, which are windblown, and pycnidiospores, spread by splashing water. Infection is highly dependent on moisture and temperature, with optimal conditions being 61 to 75°F. With warmer temperatures and changing climate conditions, the incidence and severity of gummy stem blight may increase due to more favorable conditions for the fungus.

The symptoms on the leaves include dark yellow or reddish-brown lesions appear, often starting at the leaf margins and progressing inward, leading to leaf death. On fruits the symptoms vary by crop, with winter squash often showing black rot. This rot can affect the rind, flesh, and seed cavity, with a noticeable growth of white and black fungus. Lesions on fruit are water-soaked and may lead to decay, especially at the site of attachment.

The disease management relies on chemical control (pages 128-129 of the MidWest Vegetable Production Guide) and cultural practices:

• Use disease-free seeds.
• Deeply plow crop residue after harvest.
• Rotate crops to avoid growing cucurbits in the same location for 3 to 4 years.
• Apply protective fungicides regularly.
• Avoid fruit wounding during harvest and store at 45 to 50°F to prevent postharvest rot.
• Resistant cultivars are currently unavailable.

Learn more and register at www.go.osu.edu/cucurbits

This edition of the OSU Extension Fruit & Vegetable Report was written using field observations and expertise from the following OSU Extension staff: Frank Becker, Thomas Becker, Chris Galbraith, Matt Kleinhenz, Ashley Leach, Carri Jagger, James Jasinski, Logan Minter, & Francesca Rotondo. 

Vegetables

Much needed rain has fallen across parts of Ohio to alleviate the dry weather – too much in some areas, which has caused standing water in fields that has harmed some plantings. This provides a good opportunity to discuss how to treat produce that may come into contact with floodwaters. 

One thing that might be good to clarify up front is the difference between floodwaters and pooling. Pooling occurs when there is a depression in the topography of the land where irrigation or rain water may collect. Standing water from pooling is not considered to be high-risk with regard to produce safety. Flood water comes from water that is flowing or overflowing from heavy rain events that may pick up contaminants and other things as it moves across the landscape. These contaminants include, but are not limited to bacteria, molds, human and animal waste, fungi, and other pathogens. Not only could these contaminants lead to rot issues in produce, there is also a significant food safety concern with produce that comes into contact with floodwaters. Any produce that comes into contact with floodwaters should not enter the food chain. If there are any questions or uncertainty, you can do a risk assessment of your flooded field. More information on flood risks and conducting a risk assessment can be found in this fact sheet on Ohioline: https://ohioline.osu.edu/factsheet/anr-27 

Necrosis beginning along leaf edges is one symptom of bacterial canker in tomato. Photo source: Dan Egel, Purdue University.

Bacterial diseases are still being reported, including bacterial canker in peppers and tomatoes. Reports of severe feeding from cucumber beetles and squash bugs is ongoing – some squash varieties such as Taybelle seem to be particularly attractive to these insect pests. Populations of spider mites and brown marmorated stink bug have seen an uptick. According the the recent OSU C.O.R.N newsletter, trap counts for the sweet corn caterpillar pests corn earworm and western bean cutworm are fairly low across the state at this time.

Late blight has been confirmed in tomatoes in Western New York and Western Pennsylvania. Now is a critical time to be scouting for late blight in potatoes and tomatoes. You can utilize the University of Wisconsin late blight disease risk model for the upper Midwest to help determine if conditions have been favorable for disease to occur. This model can also be used for several other disease and pest issues in our area. 

Example of a late blight lesion on potato foliage. Photo Source: Gerald Holmes, Strawberry Center, Cal Poly San Luis Obispo, Bugwood.org

Fruit

Educators are trapping for spotted wing drosophila (SWD) in blackberries and other small fruits. Populations were high and have only dropped off just recently. During periods of high SWD trap catches, it can be beneficial to do a salt test to get a sense of the level of infestation. You can conduct a salt test by placing a number of fruit in a small container with some water and salt. It can help to mash the berries a bit to help coax out any SWD larvae. Any larvae that were in the berries should be drawn out and will float to the surface of the water. A salt test can help growers determine how effective their pest management program is compared to just going off of trap counts. With SWD, we will likely see decent numbers in traps once they are present throughout the season. High trap counts can be alarming, but aren’t always what we want to base the success of our spray programs on. The salt test can help us see if we are managing populations enough to prevent berries from becoming infested with larvae. If we don’t see any larvae after conducting a salt test, this could be a good indicator that our pest management program is effective.  

Anthracnose crown rot has been confirmed on the crown and runners of strawberries. Anthracnose is a fungal disease caused by several species of Colletotrichum. Crown rot of strawberries is typically the result of infection by Colletotrichum fragariae. Mild winters have allowed for continued northward expansion of this disease. Accordingly, we have continued to see an increased impact on strawberry plants, with losses due to anthracnose crown rot. In an OSU Fact Sheet written by Mike Ellis and Omer Erincik (PLPATH-FRU-16), several strategies are recommended for prevention and management. First, it is important to start off with disease-free plants. It is also important to irrigate correctly, reducing overhead irrigation if possible, but also providing moisture to plants after harvest to prevent stress on the plant from excessively dry conditions. Mulching can also help reduce disease incidence by reducing soil splash. If you have infected plants, remove them from the planting, including berries and as much of the plant as possible. Weed control can also be impactful in reducing disease inoculum as several weed species can serve as alternative hosts for this disease. Overall, sanitation is highly important for successful prevention and management of anthracnose in strawberries. 

Excess fertility and heat caused fruit abortion in strawberries and other small fruit. It is recommended across all crop types that fertilization is not done during times when plants are under heat and drought stress. Not only can this burn and stress plants, but without adequate soil moisture, the nutrients applied will not be available for uptake via the root system. There needs to be moisture available to allow for the nutrients to enter the soil solution and move into the roots through mass flow.  

Dr. Ashley Leach, Assistant Professor of Specialty Crop Entomology with OSU, has provided the comprehensive fruit insect pest update below, including figures and tables:

Stink bugs are here. Some sites with large influxes (>20/bugs per trap). BUT, most sites have only a few bugs (0-3 bugs/trap). Codling moth counts are lower, but not at zero. Oriental fruit moth is hitting its third generation throughout the state – treat if you catch >8 moths/trap. Mite and aphid populations are pretty low this week. We noticed a HUGE natural enemy population with lots of “good” guys (ladybugs, lacewings and minute pirate bugs).

For those of you near the Northeast side of the state or receiving bins from the Mid-Atlantic, watch out for Spotted Lanternfly. This new invasive insect has a limited impact on tree fruit, but will harm grape.

**These updates include NEWA weather modeling which estimates insect development based on growing degree days. If you’re interested in how that works, you can follow this link: https://newa.cornell.edu/crop-and-pest-management. **

As mentioned, stink bugs (Brown marmorated stink bug and green stink bugs) are present in orchards. If you see an influx, consider one of the products in the table below, but apply sparingly since certain products will make mites and aphids worse (below).

Mites seem to be held in check recently. If needed, consult the miticide chart below. Make sure to take the product efficacy into account (****=best control,***= good control, **=fair control, *=poor control).

Oriental Fruit Moth is in its 3rd generation in the south – applications may be needed in higher pressure areas. Options for applications are in the chart below. Make sure to take the product efficacy into account (****=best control,***= good control, **=fair control, *=poor control).

Codling Moth –  If treating the second generation, rotate insecticides to feature a different active (IRAC code) than what you sprayed in May. If facing high pressure, >5 moths/trap, make additional insecticide applications. Some options are also included in the chart below.

As a reminder, be sure to always consult your pesticide label and regional pest management guides.

For more information or if you have questions, please reach out to a member of the Fruit & Vegetable team or your county extension educator.

This edition of the OSU Extension Fruit & Vegetable Report was written using field observations and expertise from the following OSU Extension staff: Frank Becker, Thomas Becker, Chris Galbraith, Gary Gao, Melanie Ivey, Carri Jagger, Dan Lima, Diane Miller, Francesca Rotondo, Ryan Slaughter

Vegetables

Tobacco hornworm. Photo by Ryan Slaughter, OSU Extension.

Hot, humid conditions have brought upon bacterial diseases in fruiting vegetables. Management of bacterial diseases can be challenging and frustrating. Foliar bacterial diseases are best managed with an integrated approach of sanitation, selection for disease resistance, and application of effective bactericides. There are 2 main groups of bacteria that cause diseases in plants, and they are Pseudomonas and Xanthomonas. Pseudomonas has a favorable temperature range of 60-75 degrees fahrenheit. Xanthomonas has a favorable temperature range of 77-86 degrees fahrenheit. Once present on the plant, the bacterial infection may appear to be inactive during periods of unfavorable conditions, however, the infections become active again when conducive environmental conditions return. 

Symptoms of bacterial disease present on leaves and fruit of tomato. Photos by Frank Becker, OSU Extension.

Bacteria can be easily spread via splashing rain, plant to plant contact, human activity, insect activity and on equipment. It is critically important to properly diagnose foliar lesions observed in your crops to allow you to take proper care and precaution, especially if the disease is found to be bacterial. Aside from using clean seed and following proper sanitation practices and other cultural crop management recommendations, utilizing chemical control products such as copper, mancozeb, certain botanical oils and Bacillus species can help to combat bacterial infections. Always read the label to ensure that the product that you are considering using has activity against bacterial pathogens. 

Pith necrosis, also a bacterial disease, has been observed in tomatoes. The only strategy for managing pith necrosis is prevention by avoiding favorable conditions, in particular excessive nitrogen. Copper fungicides are not able to provide control because this soil-borne bacterial pathogen is inside the plant.

Fungal diseases are also being reported, including Septoria leaf spot in tomatoes and Alternaria in melons. Downy mildew (clade 2 that affects cucumber and cantaloupe) has been found in at least five Ohio counties to date. Samples with yellow vine decline and bacterial wilt have been coming into the diagnostic lab. A reminder that when sending samples into the lab, make sure to include the full plant with roots if possible.

The 2nd generation of flea beetles continues to cause trouble in young cole crops. Spider mites are also seeing an uptick with the recent scorching weather. Corn leaf aphids are being observed around the Great Lakes region, affecting mostly sweet corn.

Corn leaf aphids on sweet corn tassel. Photo by Chris Galbraith, OSU Extension.

It’s getting to be that time of the year where we might have some of our early crops reaching the end of their productivity. Whether it’s cucurbits or cole crops or anything that we got planted early, we are now left with trying to figure out what to do with this now unproductive space in our field or garden. You have a couple of options:

Succession Planting: You may decide that you really don’t want to be done with growing something just yet. You could consider succession planting. Succession planting is a way for you to grow a crop throughout more of the growing season, instead of, for example, just growing a cool-season crop in the spring and being done for the rest of the season or waiting until you can plant warm-season crops and only having the one crop for the season. In the right circumstances, you could have an early cool-season crop, followed by a warm-season crop, followed by another cool-season crop depending on the amount of time it takes each crop to reach maturity. For example, you might plant something like lettuce or radishes early in the spring, then after you have harvested that crop, you might come in and plant something like beans, tomatoes, peppers, etc.

Done for the season: Maybe you are done planting new crops for the season, and that’s just fine! There are some best management practices though we can implement to make sure we are keeping our other crops protected and healthy. If you have a crop that is done producing, and perhaps starting to senesce, it is best to remove that plant material from the garden or field. Even though you might be done with the plants, pests and diseases certainly are not. If left in the garden or the field, this plant material can serve as a harborage for pests and diseases that could still impact our crops that are still growing. Removing this plant material gets rid of a favorable environment for things that would otherwise pose a threat to the rest of our garden or field. You can either physically remove the plant material and burn it or compost it, or you could work it into the garden or field to bury the plant material. 

So, whether you are done with an area in your garden or field or if you plan to keep planting, don’t just leave all that plant material behind. End of season best management practices can set us up for success for the rest of this season and for the next growing season! 

Fruit

Hot and dry weather has continued to promote population development of European red mites and two-spotted spider mites. This problem can be made worse with applications of certain insecticides that wipe out beneficial insects and natural enemies that would otherwise be keeping the mite population in check. Codling moth and oriental fruit moth seem to be slowing down in eastern Ohio.

Strange spots were observed on apple across the Great Lakes region. Some cases from other states have been confirmed as blister spot (Pseudomonas). Blister spot tends to occur more frequently in cool, wet weather which has not been characteristic of the season in much of Ohio. The apple variety Mutsu is particularly susceptible to blister spot. Ohio cases were not found to be bacterial in nature – final diagnosis concluded the symptoms were likely due to spray injury that occurred during recent high temperatures. 

Blister spot in apple. Photo source: John Hartman, University of Kentucky, Bugwood.org.

Some apple trees this year were observed to have “mummy” fruit that didn’t size up and develop properly but still remained on the tree. MaxCel, a plant growth regulator used for thinning, seems to cause this issue in some years with different varieties. Going back through to hand-thin is too labor intensive and so growers often resort to having workers  just harvest around the undeveloped fruit.

The hot weather has also resulted in sunscald concerns in small fruit and orchards. Once sunscald occurs, the fruit can become susceptible to other pathogens and secondary pests. 

Strawberry foliar and crown rot diseases seem to be widespread this year. Much of the management for this is preventative, such as practicing sanitary propagation methods. Blueberry season is wrapping up in many areas. High tunnel blackberries are being harvested and field blackberries are close to ripening in northern Ohio. Blackberry yields have been high in central and southern Ohio. Newer blackberry varieties such as Ponca that been planted more and more in recent years have lower acidity and are sweeter, improving sales and customer satisfaction.

For more information or if you have questions, please reach out to a member of the Fruit & Vegetable team or your county extension educator.

Author: Chris Galbraith, Ohio State University Extension/Michigan State University Extension

This article was originally posted on Michigan State University Extension News.

Photo courtesy of MSU Plant and Pest Diagnostics.

Post-harvest rots occurring in vegetable crops can deal a brutal blow both financially and in terms of morale. All the investment and hard work of growing produce is lost if the crop spoils before it can be sold. Fortunately, many of the factors influencing prevalence of post-harvest rots are well-known and there are actions growers can take during the growing season, at-harvest, and post-harvest to reduce losses from premature decay.

What causes a rot?

Once vegetable crops are harvested, they are cut off from their source of nutrients and water. However, the produce continues to respire, using up its energy reserves and releasing water during metabolism. Cellular breakdown occurs as the produce spends its energy/moisture savings without any means of replenishment. As the produce degrades in quality, it becomes more susceptible to colonization by rot-causing pathogens.

There are many different microbes that bring about premature decay if they are able to infect vegetable crops during the different stages of growth and storage. These organisms may be latent pathogens, which can remain quiescent upon entering the crop and begin colonization of host plant tissue during storage (eg. Colletotrichum). Pathogens may also begin colonization immediately after infection, in which case spoilage occurs rapidly. Many rot-causing microbes are considered weak pathogens (eg. different bacterial soft rots), which cannot penetrate healthy plant tissue but instead require wound sites (nicks, scrapes, bruises) to enter and begin colonization. Table 1 lists common post-harvest pathogens for various vegetable crops. Many of these pathogens not only occur in storage but can also cause disease during the growing season.

The disease triangle is a useful framework. Spoilage occurs if the pathogen encounters a susceptible host in conditions that are favorable for infection. Post-harvest spoilage occurs more frequently in warm, wet and humid conditions. High temperatures encourage pathogen activity and increase the rates of produce respiration/ripening. Excess moisture on produce encourages pathogen activity and entry into plant tissue. Similarly, high relative humidity supports free moisture accumulation on vegetable crops in storage. Controlling these factors mitigates risk of premature spoilage and increases the shelf life of vegetable crops.

The disease triangle is a useful framework – spoilage occurs if the pathogen encounters a susceptible host in conditions that are favorable for infection.

Best management practices

Steps can be taken throughout production and storage to minimize losses from post-harvest rots. During the growing season, preventing fruit from coming into contact with the ground using plastic or organic mulch keeps produce cleaner and reduces opportunities for infection. Mulch also helps to reduce soil splash during irrigation or rainfall events, further limiting pathogens from being moved onto susceptible tissue.

Minimizing damage to produce throughout the season reduces wound sites and therefore pathogen entry points. This means gentle handling of vegetable crops at harvest and reducing the number of times produce is touched to minimize accidental skin breaks or bruises. Protecting vegetables from insects, wildlife, and environmental damage (hail, sunscald, wind) also reduces wound sites. Culling produce that is already damaged can reduce spread of spoilage in storage bins. Harvesting at proper maturity also helps optimize shelf-life.

Keeping vegetables cool can go a long way toward preventing premature spoilage. Harvesting during the coolest part of the day and removing the field heat from vegetables immediately after harvest is key. There are different pre-cooling methods available to rapidly bring down the temperature of produce prior to storage, including room-cooling, forced-air cooling, hydrocooling, package icing and vacuum cooling procedures.

Storage temperature and humidity recommendations vary by vegetable crop and following the right guidelines is important for maximizing shelf life. Specific storage recommendations and information on pre-cooling methods can be found in the Guide to Vegetable Production in Ontario (OMAFRA Publication 839). Maintaining proper temperature is also important to prevent chilling or freezing injury, which presents as sunken, water-soaked spots on susceptible produce.

For certain storage crops, curing is a crucial step for optimizing shelf life. Curing allows skins to dry out and harden, increasing protection against infections that cause rot. The area used for curing should always be a well-ventilated space with adequate air circulation. Recommended curing guidelines for several storage vegetable crops are listed in Table 2.

In conclusion, there are various factors that contribute to the occurrence of post-harvest rots. By taking the right action during the growing season, at-harvest, and post-harvest, losses from premature decay can be minimized and crop quality preserved.

Powdery Mildew Detected – This week marks the first week powdery mildew was detected in the pumpkin plots in South Charleston at the Western Ag Research Station. There have been reports of PM being found a week earlier in Wayne County. At the station, the amount of disease detected in the trial was extremely minor; only three white colonies on ca. 60 leaves, top and bottom leaf surfaces inspected, on July 18. Powdery mildew can multiply in the canopy rapidly given warm and humid conditions so the recommendation is to begin treatment when the first colonies are discovered. Today, nine treatments for the powdery mildew fungicide trial on pumpkins were applied. Major fungicides being tested include Milstop, Cease, Switch, Gatten, Procure and Quintec. Results of the trial will be reported when the trial is completed mid-September.

Striped Cucumber Beetle Update – The summer generation of striped cucumber beetles emerged in South Charleston around two weeks ago and have moved off of the foliage and primarily into flowers at this point in the season. Treatment for beetles in the flowers is not recommended as this will only cause significant harm to pollinators in and around the field, plus cause other issues with pest insects (see below).

Sticky panel with rootworm attractive lure

On a related note, the striped cucumber beetle attractant study being conducted at the Western Ag Research Station is about ¾ done at this point. Of the three attractants being tested for striped or spotted cucumber beetles, none seem to stand out as being hyper attractive to these two beetles. There is one lure that is very effective against the Western corn rootworm beetle, which has also begun to emerge from corn fields in the past few weeks.

Aphid infested pumpkin plant

Green lacewing egg in center of circle

1 black circle around ladybug eggs, 2 circles around golden aphid mummies

Aphids Rising…But Why? – What do you get when you apply a pyrethroid insecticide to a pumpkin field in early July? Answer, most likely a field full of aphid covered plants. Why the surge in aphids? This is attributed to the highly toxic nature of the pyrethroid chemical class to natural enemies in the field that are actively suppressing the aphid population. In the photos, you can see some major aphid predators re-establishing on the aphid infested leaves; ladybug eggs, green lacewing eggs and aphid mummies (evidence of parasitoid wasps). The lesson here is unless you have a known pest to control in a pumpkin field which is over threshold, resist the urge to spray a broad-spectrum insecticide. If a treatment must be made, consider selecting products that are less likely to flair aphids or other secondary pests.

In an IPM context, it is important to protect plants with fungicides from diseases such as powdery or downy mildew when they are detected above threshold. Over the past few years, researchers have begun to understand the importance of not adding both fungicides and insecticides to the same tank mix due to harmful synergies, some that are known and many that are unknown, on pollinators and potentially other insects like natural enemies. For a deeper dive into the negative synergy of mixing fungicides and insecticides, Cornell University recently published this bulletin. https://cornell.app.box.com/v/ProtectionGuide-FieldCrop2023.

Cornell Pollinator Guide

World’s smartest toad?

Amphibian Pest Management? – While scouting for powdery mildew on Thursday, I came across this toad cleverly parked at the edge of a pumpkin flower, no doubt waiting for a juicy opportunity to nab a few beetles or bees. First time I have ever seen this!