Vegetable Weeds

OSU Extension Bi-Weekly Fruit & Vegetable Report – October 17th, 2023

The OSU Extension Fruit & Vegetable Report is written/published collectively by OSU Extension staff across the state. 

Biological Soil Health

When it comes to supporting healthy soils, the physical and chemical aspects of soil quality are often highlighted. However, the importance of biological activity and diversity, and how it influences soil structure and chemical properties (pH, electrical conductivity, etc.), is becoming increasingly appreciated in modern farming. As we discover more about the different microbe-microbe and microbe-plant interactions unfolding in the soil habitat, we can create better farming practices that optimize crop health and soil quality.

Three areas of soil health: physical, chemical, and biological. Image courtesy of University of Massachusetts. 

The source of and final destination of all soil life is soil organic matter (SOM). SOM consists of biological material in the soil, derived from plants, fungi, animals, and other organisms, that are in various stages of decomposition. Certain forms of SOM break down quickly and provide nutrients for crop use, others are more stable (i.e. inaccessible to microbial decay) and contribute to aggregate stability and tilth. A SOM content of 5% in mineral soils is considered high; in muck soils, SOM can be as high as 80%. Conservation ag practices like reduced tillage and cover cropping are used to support high levels of SOM for improved nutrient cycling, soil structure, and cation exchange capacity. 

The food webs that produce SOM are characterized by an astonishing diversity of soil life made up of bacteria, fungi, archaea, nematodes, protozoa, and other microfauna, as well as the larger organisms like springtails and earthworms higher up the food chain. These organisms not only drive nutrient cycling through consuming and contributing to SOM, but can influence crop health through more specialized relationships. Plant-growth promoting rhizobacteria that interact with plant roots can boost crop productivity by producing hormones, fixing atmospheric N, solubilizing P for increased availability, and inducing plant resistance to pathogens. The growing biologicals industry (biopesticides, biofertilizers, and biostimulants) is based on the premise that certain organisms benefit crop health through either direct interactions or interactions with other soil life. 

Keeping in mind how soil biodiversity and activity affect soil health through the lens of SOM and interactions between organisms can help us make decisions that support crops by maintaining a thriving, balanced soil habitat.

Examples of soil organisms at different scales – Microfauna: Azospirillium soil bacteria (top), Mesofauna: tardigrade (middle), Macrofauna: earthworm (bottom). Photos courtesy of Science Source (top), National Geographic (middle), Dan Brekke – Flickr (bottom).

Crop Updates

Vegetables

Cucurbits

Plectosporium leaf blight is being detected. Continue to watch for aphids, cucumber beetles and squash bugs. Significant damage was detected within the last week in harvested pumpkins due to large populations of cucumber beetles. Aphids can still be found in green foliage, and may be spotted via large accumulations of honey dew beneath healthy foliage.

Cucumber beetles feeding on harvested pumpkins. Photo by Frank Becker, OSU Extension.

Cole Crops

Alternaria leaf spot is being observed in brassicas. This pathogen is supported by warm, wet conditions. Cultural practices for reducing alternaria pressure include increasing crop spacing for improved airflow, crop rotation, tilling under crop residue after harvest and controlling brassica weeds (shepherd’s purse, wild mustard, wild radish, yellow rocket, etc.)  to decrease disease inoculum. Treating seed with hot water prior to planting may also help  to decrease prevalence of this seed-borne pathogen. Consult the Midwest Vegetable Guide for fungicide options in Brassicas.

Tomatoes/Peppers

Hoop house tomatoes are nearing the end. Powdery mildew, bacterial diseases, aphids, and other pests are all being observed under plastic. Late blight and early blight are prevalent in remaining field tomatoes. 

Anthracnose is continuing to be an issue on peppers and tomatoes. Infested fruits rapidly decline in quality and are unmarketable. Lesions are typically observed as sunken, round lesions on the fruit. At times you may also be able to see the salmon colored spores within the lesion on the fruit. 

Anthracnose on peppers. Photo by Frank Becker, OSU Extension. 

Fruit

Many orchards are nearing completion of harvest and pest monitoring traps are being taken down for the season. As tree fruits are harvested and leaves begin to fall, it may be a good opportunity to take a closer look at your trees and scout the trunk and branches for presence or evidence of insect pests such as scale and borers. Scouting for these pests now can help you make adjustments to your integrated pest management program.

October Small Fruit Updates

Dr. Gary Gao, Professor and Small Fruit Specialist, CFAES South Centers. The Ohio State University

Update on Long Cane Raspberry Project:

We are only getting a few straggling raspberries from our long cane raspberry trial at OSU South Centers in Piketon during the week of October 6, 2023. There were only enough for Gary to snack on. Pictured in the first photo is Kweli®. As you can tell from the picture, fruit color is still looking quite nice. Kweli® is an everbearing variety that is capable of producing two crops inside a high tunnel and out in the open field. Follow this link for more information on the variety: https://www.abbreeding.nl/varieties/kweli/?lang=en

We are still fine-tuning the method of growing long cane Kweli®. We just wrapped up our 2021-2023 Specialty Crop Block Grant (SCBG) funded by Ohio Department of Agriculture (ODA). There is a lot more to learn about this highly innovative production method. Fortunately, we received another SCBG from ODA to do just that!

Kweli® fruits. Photo by Dr. Gary Gao, The Ohio State University.

Gary was able to find several Tulameen raspberries from our long cane raspberry trial plot. This is definitely too late for the Tulameen harvest since it is a summer-bearing variety which does not produce fruits on primocanes. It was still neat to check them out. Earlier in the season, we harvested a lot of beautiful Tulameen fruits. Some of our grower cooperators were able to sell them for $9 per pint in a Columbus farmer’s market. Raspberry bushes in a long cane production system can produce 22,000 lbs. per acre! Tulameen is well suited for long cane raspberry production and is well known for its large fruit size and excellent taste! Follow this link – https://www.researchgate.net/publication/292928034_’Tulameen’_red_raspberry – for more information on Tulameen variety.

Tulameen fruits picked in October from our long cane raspberry trial. Photo by Dr. Gary Gao, The Ohio State University.

Late Leaf Rust on Raspberries:

Gary noticed that some of the raspberry bushes in their raspberry trial had late leaf rust. Late leaf rust on raspberry is a fungal disease. Follow link – https://ohioline.osu.edu/factsheet/plpath-fru-17#:~:text=Late%20leaf%20rust%20is%20caused,rust%20fungus%20is%20not%20systemic. -for more information on symptoms and management of this disease. Do not confuse this disease with orange rust of brambles. Fortunately, red raspberries are resistant to orange rust.

Late leaf rust on raspberries. Photo by Dr. Gary Gao, The Ohio State University.

Fall is for Figs in Ohio!

Even though fall is typically for apples, mums, and pumpkins, it is also for figs – well hardy figs for that matter. Gary has been picking hardy figs from their fig planting at OSU South Centers in Piketon from early September to now. The figs will keep ripening until frost. A high tunnel will extend the harvest season.  Our figs were from another Ohio Specialty Crop Block Grant funded by ODA a few years ago. The varieties in our trial are Brown Turkey, Hardy Chicago, and Olympian. Brown Turkey and Chicago Hardy performed the best in our trial. Follow this link https://ohioline.osu.edu/factsheet/hyg-1439 for more information.

OSU hardy fig trial. Photo by Dr. Gary Gao, The Ohio State University.

Brown Turkey figs from the hardy fig trial at OSU South Centers in Piketon. Photo by Dr. Gary Gao, The Ohio State University.

Berry Production Workshops Presented by OSU Extension in Medina County

I will be going to Medina County on Friday, October 27 to give two talks, one on blueberries and one on raspberries. Ms. Ashley Kulhanek, the Ag. and Natural Resource Educator, is organizing the program. I will show gardeners and growers how to grow blueberries and raspberries. Please call OSU Extension in Medina County at 330-725-4911 for more information and to RSVP!

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This is our last bi-weekly report for the 2023 season. Thank you for reading and please feel free to direct any feedback on the report series to Chris Galbraith at galbraith.108@osu.edu.

Upcoming Events

December 5 – 7, Grand Rapids, MI, Great Lakes Fruit, Vegetable, & Farm Market Expo 

January 15 – 16, Columbus, OH, 2024 Ohio Produce Network

February 15 – 17, Newark, OH, 2024 Ohio Ecological Food and Farm Association (OEFFA) Conference

 

OSU Extension Bi-Weekly Fruit & Vegetable Report – September 28th, 2023

The OSU Extension Fruit & Vegetable Report is written/published collectively by OSU Extension staff across the state. 

View a recording of the OSU Extension Bi-Weekly Fruit & Vegetable Report updates below:

Strip Tillage

Strip tillage is a form of conservation tillage that attempts to combine the benefits of no-till and conventional tillage by working only the area where the crop will be planted. Leaving residue cover over the majority of the field protects the soil against erosion and helps to build organic matter, improve aggregate stability, and boost other indicators of soil health. Working the soil in the strip zone warms the soil faster and prepares a better seedbed to support plant growth. 

Components of a strip till unit – A) lead coulter for slicing through residue, B) row cleaners for parting residue, C) shank for fracturing and lifting soil, D) berm-building coulters to shape tilled soil into strip, & E) rolling basket for creating level seedbed. Photo courtesy of Orthsman/Unverferth Manufacturing. 

 

Strip-till in sweet corn stubble. Photo by Chris Galbraith, OSU Extension.

While strip till targets the benefits that come with integrating the two systems, there are downsides to consider as well. These mostly involve issues with cover crop and/or residue interference with growing the crop. Vigorous cover crops need to be terminated in a timely fashion and crop development can still be delayed in strip-till if the season begins cold and wet. Pests like slugs and voles can also build-up with the increased residue cover. The cost of the equipment can also be a substantial investment which creates a barrier to entry for many growers.

Many vegetables can be grown in strip tillage systems, including cucurbits, sweet corn, snap beans, potatoes, cole crops, carrots, and more. Recent studies at Michigan State University have found a slight yield increase from strip till in vegetable crops, but many of the issues mentioned can impact this (climate, residue management, pest pressure). It is important to consider the factors that go into making strip till a successful venture in order to make the most of the equipment and the practice.

For additional info on strip till in vegetables, check out this website on strip tillage from the Cornell Small Farms Program. 

Wildlife Control in Fruits & Vegetables

This season has been severe in terms of wildlife damage in specialty crops. Animals like deer, groundhogs, voles, raccoons, and birds have caused major losses on some farms. Dr. Marne Titchnell, wildlife program director for OSU Extension, recently gave an in-depth presentation at Farm Science Review on different wildlife mitigation strategies for growers. The information and slides can be found on her blog through the link below:

Managing and Preventing Damage from Wildlife in Fruits & Vegetables

OSU Extension Center for Cooperatives

Opportunities abound for farms when it comes to teaming up to save money and improve effectiveness through joint purchasing, collaborative marketing, and other similar practices. These types of partnerships between farm businesses is captured by the cooperative or “co-op” model where growers access resources and savings by acting together and making decisions as a group in certain scenarios. The Center for Cooperatives at OSU specializes in these sorts of opportunities and can offer guidance to growers who are interested in leveraging the benefits of organizing for collaborative business purposes.

Find more information at the center’s website. Read more about the topic of collaborative marketing in this recent article on the Center of Cooperatives blog.

Crop updates

Vegetables

Cole Crops

Heavy cross striped cabbageworm and imported cabbageworm feeding is still being observed in some brassica plantings. Aphids have made a late season push in brussel sprouts, cabbage, cauliflower and broccoli plantings. Cabbage aphids are typically a grayish color, and are often found amongst a waxy, white secretion which covers their body. Reproduction rates of these aphids are highest in temperatures between 50-68F. Scout for these pests on the underside of younger leaves, between leaf layers and on flower buds or seed stalks. It is recommended to treat cabbage when you see 1-2% of plants infested with aphids. There are a number of products that can be used to treat aphids in cabbage including Movento, Sivanto, Assail, Exirel and Beleaf. Prioritize products that have reduced toxicity (e.g., Beleaf) which will conserve natural enemy communities. Refer to the Midwest Vegetable production guide for other options. 

Cabbage aphid infestation. Photo by Frank Becker, OSU Extension. 

Cucurbits

Cucurbits are seeing upticks in a variety of beetles in flowers and fruit. These include corn rootworm species. Spotted cucumber beetles are active. Aphids are also beginning to be found with some more frequency in the fall vine crops. Squash bugs are also active within the crop. Most cucurbits do not have blooms in fields, so pyrethroid and carbamate applications may be applied (e.g., Sevin, Pounce, Capture). Refer to the Midwest Vegetable production guide for other options.

The pumpkin crop has been strong in Ohio this season. Many growers in northwest Ohio were able to manage downy mildew with fungicides. Plectosporium blight has been causing some problems for growers where fungicide spray coverage may not have been as thorough as desired. Most fungicide spray programs being used are adequate to limit impacts from plectosporium blight. Spray penetration into the canopy and coverage across the field is as important as selecting the right product.

Plectosporium blight on pumpkin, identified by light colored lesions on fruit, handles, and vines.  Photos by Frank Becker, OSU Extension.

Fruiting Vegetables 

Late blight has been confirmed in several tomato fields in and around Wayne County. Bacterial diseases have also begun to start, and with cool mornings and heavy dews, it will become increasingly more difficult to manage. 

Several high tunnel producers have reported dealing with broad mites/cyclamen mites in their high tunnel peppers. The mites feed on the fruit while it is still developing and their feeding damage causes the peppers to become russested and misshapen. The leaves may also appear distorted, almost as if they were drifted with herbicides. Keep in mind that these mites are in a different group than two-spotted spider mites. Therefore, it’s important to select control options that are appropriate and effective on this species. Sanitation and crop rotation are also important cultural control measures that need to be taken when dealing with mites in high tunnels.  

Onions 

Although the growing season is behind us for onions, curing is still ongoing, and some growers have reported some challenges with curing. Make sure that you are providing the proper conditions for curing onions. Less than ideal conditions will result in frustrations and losses of product. Ideal conditions are warm, dry, well ventilated areas. Ideal temperature range is between 75-90F. The other factor that contributes to losses while curing is not curing the best graded onions. Curing is not an attempt to bring quality back, only preserve it. Grading hard for only the best onions to be cured will help reduce the chance that rots begin to develop. Take note of any disease or insect issues that you have observed this year and use these notes to help you next year. Onions that may have had heavy thrips loads, or untreated disease infection during the season are not going to hold up as well as desired during the curing process. 

Green onions are seeing thrips populations slow down. Typically, thrips populations will decrease as we enter into Autumn and see these species move onto weedy hosts. 

Fruit

Sanitation is an important component of an integrated disease management program. In small fruit and tree fruit alike, there are diseases that can over winter on infested fruit, foliage and branches. As the season winds down, it is still important to scout for diseases that may be present, identify the disease and have a plan of action to manage the disease. Finding and removing mummy fruit, which are dried and shriveled fruit that are typically full of fungal structures, will help to significantly reduce disease inoculum from the production area. Too, mowing and mulching or raking away the leaves from around the trees and bushes reduces the amount of viable inoculum that may be overwintering in foliage. Much progress can be made towards disease management with efforts made in the fall. Taking these steps, and committing to them long term, helps to break disease cycles and reduce the overall pathogen load over time. 

Fruit rots are being observed in apples, including white rot and bitter rot. Bitter rot is common in apples during warm, wet conditions. For more information, take a look at this OSU article on bitter rot in apple. Marsoninna blotch is also found on apples. 

The pawpaw crop in Ohio this season has been later and smaller than past years. Pawpaw is a niche crop that is gaining popularity with Ohio consumers and can be used as an ingredient in specialty craft beers, ice cream, and other value-added items. For more information on pawpaw production, check out this factsheet from Cornell University. Learn more about the pawpaw industry in Ohio by visiting the Ohio PawPaw Growers Association website.

Pawpaw fruit cluster. Photo by Clemson University. 

 

Upcoming Events

September 30, Albany, OH OEFFA CSA Veggie Farm Tour

December 5 – 7, Grand Rapids, MI, Great Lakes Fruit, Vegetable, & Farm Market Expo 

January 15 – 16, Columbus, OH, 2024 Ohio Produce Network

February 15 – 17, Newark, OH, 2024 Ohio Ecological Food and Farm Association (OEFFA) Conference

 

OSU Extension Bi-Weekly Fruit & Vegetable Report – September 15th, 2023

The OSU Extension Fruit & Vegetable Report is written/published collectively by OSU Extension staff across the state. 

View a recording of the OSU Extension Bi-Weekly Fruit & Vegetable Report updates below:

Farm Science Review 2023

The Farm Science Review (FSR) is one of the nation’s premier farm shows and one of OSU Extension’s largest, most far-reaching educational programs. The event will be held at the Molly Caren Agricultural Center near London, Ohio on September 19th – 21st. The OSU Extension Fruit & Vegetable Team will be hosting a tent all 3 days that will feature presentations from academic and industry speakers on a variety of topics, including nutrient management, entomophagy, integrated pest management, variety trial results, farm marketing, and more. The OSU Extension Fruits & Vegetables exhibit will be located near the gazebo near the Utzinger Garden (booth 385). We hope to see you there!

Check out the 2023 Farm Science Review Program for further information.

Speaker schedule for OSU Extension Fruits & Vegetables exhibit at FSR 2023. Note: There will also be a presentation by Dr. Marne Titchnell, Extension Wildlife Program Director for OSU,  on wildlife management in fruits & vegetables on Wednesday, September 20th from 1:30 – 2:00 PM.

Purple carrot-seed moth detection

The OSU Plant & Pest Diagnostic Clinic (PPDC) recently received an insect sample that was identified to be purple carrot-seed moth (Depressaria depressana), a known pest of crops in the Apiaceae family. This was the first report of purple carrot-seed moth found in Ohio, though it has been found in neighboring states. The insect feeds on the flower heads of crops like carrot, parsnip, dill, celery, parsley, and more, but it is yet unknown if it will be an economically important pest of these crops in Ohio. Check out the article from PPDC for more information.

Please report any suspected larvae/adults with pictures to entomology@osu.edu or ppdc@osu.edu.

Purple carrot seed moth larvae (top) and adult (bottom). Photo by Iowa State University Extension (top) and University of Wisconsin-Madison Department of Entomology (bottom). 

Crop updates

Vegetables

Cucurbits

Downy mildew continues to wreak havoc in cucurbit plantings this time of year. As a refresher, here is a factsheet from Michigan State University on downy mildew mitigation. Powdery mildew pressure is reported to be increasing in southern Ohio. Striped cucumber beetles populations are declining in central/northeast Ohio and transitioning more towards higher numbers of corn rootworm beetles. Western corn rootworm, a look-alike of striped cucumber beetle, also feeds on cucurbits and can impact yield if heavy populations are present. Check out this article from Iowa State University for information on identifying different rootworm beetle pests. 

Virus symptoms are being observed in some melon plantings. There are various aphid-vectored potyviruses that affect cucurbits and they can be hard to differentiate from one another, though control practices are similar for all of them. The big 4 for cucurbit crops are cucumber mosaic virus, papaya ring spot virus, watermelon mosaic virus, and zucchini yellow mosaic virus. Like many crop diseases, management practices are preventative and include using resistant varieties or planting earlier to ensure harvest before viral symptoms appear towards the end of the season. Getting aphids under control may also minimize virus infection to some degree.

Cucumber mosaic virus – symptoms include yellowish-green “mosaic” mottling on foliage or fruit and crinkled leaves. Photo by Gerald Holmes, Strawberry Center, Cal Poly San Luis Obispo, Bugwood.org.

Papaya ringspot virus – symptoms include wrinkled leaves and discolored, bumpy fruit. Photo by Mary Ann Hansen, Virginia Polytechnic Institute and State University, Bugwood.org.

 

Watermelon mosaic virus – symptoms include wrinkled leaves and geometric patterns on fruit.  Photo by Dorina Pitorac, European Plant Protection Organization.

Zucchini yellow mosaic virus – symptoms include blistered, wrinkled leaves and fruit with discolored bumps. Photo by University of Massachusetts Extension.

Fruiting Vegetables

Late-season aphid feeding is being observed in some solanaceous crops. Honeydew is a sugary liquid secreted by aphids and other sap-sucking insects (whiteflies, spotted lanternfly, etc.). Honeydew accumulation on crop foliage or fruit can lead to growth of sooty mold, which is a term for various genera of fungi that colonize the sticky exudate. Sooty mold does not render vegetables inedible, however, and can be readily washed off. 

Honeydew from aphids (and other sap-suckers) on plant leaves is sticky to the touch and can be colonized by sooty mold. Photos by Kansas State University Entomology (top) and Joe Boggs, the Ohio State University Extension (bottom). 

Regular bouts of rainfall as we head into the fall are leading to increased incidence of Phytophthora infection in peppers (and cucurbits). While excess water is a problem for some vegetable growers in Ohio, some parts of western Ohio still remain abnormally dry, according to the U.S. Drought Monitor. Mites have been a problem in some areas, while thrips have taken a downturn. Keeping mites under control towards the end of the season can reduce the chance of heavy pressure next season by reducing the egg load/number of overwintering adults that will become next year’s mite infestations.

Fruit

Tree fruits

Early varieties of apples are being harvested across the state. Brown marmorated stinkbug pressure is increasing. Bitter rot is starting to be observed in some orchards. Marssonina leaf blotch is also being seen in some organic orchards, where management can be difficult without the use of fungicides. Removal/destruction of leaves on the orchard floor in the fall can reduce overwintering sites for the pathogen. Black knot is being seen on some ornamental plum trees, so commercial plum and cherry growers should keep an eye out for black knot galls on their trees and promptly remove them if they see them.

Gall of black knot (Apiosporina morbosa), a fungal pathogen of plum, cherry, and other types of fruit trees. Photo by Joseph O Brien, USDA Forest Service, Bugwood.org.

Small Fruits

Preparing Brambles for Winter – Sanitation Practices for Disease Prevention
Melanie Ivey, State Fruit Pathologist and Fresh Produce Safety Specialist, The Ohio State University

Disease management of perennial fruit crops is a year-round endeavor. Many fungal pathogens survive the winter months in the soil or plant debris, infected canes or buds, or dead canes. As part of an integrated disease management program fall sanitation practices to reduce inoculum in the planting should be done.  Best sanitation practices include removing floricanes after harvest, removing diseased and dead canes, removing dead or systemically infected plants, and raking or chopping fallen leaves. Pruning debris should be destroyed by burning or placing in the trash or discarding it away from the planting. Diseased plant material should not be composted.  Pruning cuts should be sharp and clean to avoid unnecessary mechanical wounds.

The fall is also a good time to scout for and remove wild bramble populations that are near the production field. In addition to fall sanitation practices, some diseases require a dormant or delayed dormant fungicide application. For dormant or delayed dormant fungicide recommendations consult the Midwest Fruit Pest Management Guide (OSU Extension Bulletin 506).

The table below summarizes where the fungi for several common diseases of brambles in Ohio overwinter, the recommended fall sanitation practices for each disease, and whether a dormant or delayed dormant fungicide application is recommended.

Upcoming Events: 

September 19 – 21, Farm Science Review

September 27, Wooster, OH, Midwest Mechanical Weed Control Field Day

September 30, Albany, OH OEFFA CSA Veggie Farm Tour

December 5th – 7th, Grand Rapids, MI, Great Lakes Fruit, Vegetable, & Farm Market Expo 

January 15 – 16, Columbus, OH, 2024 Ohio Produce Network

February 15 – 17, Newark, OH, 2024 Ohio Ecological Food and Farm Association (OEFFA) Conference

Crop Vigor and Weed Pressure

The middle of the main season can be a pivotal stage in crop-weed relations. Weed growth may begin to overcome steps taken earlier to control it, including herbicide application and cultivation. Also, pre-harvest intervals or plant-back restrictions, concerns over potential crop damage, and other factors may limit the use of additional chemical or mechanical tactics like applied before crops emerged and closed rows. Further, weed seed produced mid-late season can increase weed control challenges in following years. Under these circumstances, vigorous crops able to slow weed growth for even a short time can be beneficial. Creating shade and utilizing water and nutrients are two ways vigorous crops can tip the crop-weed competition in the grower’s favor. The vigor and “out-grow/out-compete the weeds” factor may be most important for crops for which cultivation and herbicide options are relatively limited. The two pictures below partially illustrate the crop vigor-developing weed pressure relationship as it stands in a potato planting before the potato vines fall, the canopy opens, and vines eventually decline or senesce. A large, vigorous crop canopy as a product of the variety and good growing conditions and supportive management is its own type of weed suppression.

Electrical Weed Control in Vegetables and Field Crops

This article is provided by Chris Galbraith, MSU/OSU Extension & Jenna Falor, MSU Extension.

Late-season weed management is essential to consider when developing a weed control plan for your operation. Despite one’s best efforts, weeds can often escape early-season control. This can be a result of poor timing, missing the plants with cultivation, spray applications or flaming, or due to herbicide resistance. If allowed to reach reproductive maturity, escaped weeds can cause management problems in future years due to replenishment of the weed seedbank. These larger weeds can also harbor crop pests and diseases, interfere with harvest by obstructing equipment, or degrade final crop quality through contamination from weed residues.

Management practices for escaped weeds are notoriously limited due to the difficulty of controlling weeds when they have reached a significant size. Weed wipers use an applicator made of an absorbent material, such as sponge or a rope wick, that is saturated with herbicide and used to contact weeds growing above the crop canopy, killing the weeds but leaving the crop unaffected. The downsides of this method include a lack of herbicide options effective on larger weeds, limited efficacy on herbicide-resistant populations (depending on what product is being applied), and its unsuitability for use in organic systems. Another option is sending in hand weeding crews to manually weed the fields, which is particularly common for managing escaped weeds in vegetable production. While this method does tend to be effective, the labor is expensive, time-consuming, and hard monotonous work for employees.

The major manufacturer and supplier of electrical weeding equipment in the United States is The Weed Zapper, a Missouri-based company that began production in 2017. Electrical weed control technology has also been developed by the Brazilian company Zasso and the European companies AgXtend, Rootwave, and Crop.Zone. While electrical weeders from foreign companies are as of yet rare in the U.S., familiarizing oneself with the technology that has been developed overseas shows the versatility of this technology in different cropping systems and gives a clue as to the future of the equipment in modern agriculture.

Pro-environmental attributes of the equipment are that it does not disturb the soil and does not require the use of any chemical herbicides. Electrical weeding provides systemic control of even larger plants, making it an effective option for controlling weed seed bank inputs by terminating weeds at or prior to reproductive maturity. Similar to mechanical weeding and certain herbicides, it is non-selective and therefore caution must be taken to prevent crop injury. This typically restricts in-season use to crops with low-canopy growth habits that don’t come into the path of the electrode. While this limits the application of electrical weeding, there still remains many crops where growers might benefit from integrating this equipment into their weed control plan.

Read the full article “Electrical Weed Control in Vegetables and Field Crops”.

View the factsheet “Basics of Electrical Weed Control”.

A Potential New Nemesis for Garlic Mustard? Identifying and Reporting a Newly Arrived Garlic Mustard Specialist Aphid- Lipaphis alliarae

Join Holden Arboretum’s Natural Areas Biologist Rebecah Troutman to learn more about a newly discovered enemy of the invasive garlic mustard.  This webinar will teach participants how to find and identify Liaphis alliariae, a garlic mustard specialist aphid native to Europe. This aphid was found during the 2021 field season.  Affected plants produced twisted seed pods and puckered/wilted leaves. Given the importance of controlling garlic mustard, the novel nature of the newly discovered aphid in the United States, we are trying to better understand the impact this species has on garlic mustard- could it be a desperately needed biocontrol agent? The objective is to quantify the impact of this novel aphid on garlic mustard and map its current distribution.

Registration is now open here.

Reflex and other herbicide thoughts for Pumpkin and Squash

Thinking about weed control.

It’s the second week of April and if you grow either pumpkin or squash, the notion of weed control has undoubtedly been on your mind. On May 29 2020, Reflex herbicide (fomesafen, Syngenta) was given a 24(c) label (local needs exemption) in Ohio for use on cucurbits.

What does Reflex bring to the weed control game to complement other currently labeled herbicides? Reflex is a pre-emergent herbicide which should be applied after seeding but before crop emergence. The primary fit would be against small seeded broadleaves such as lambsquarters, purslane, common ragweed, nightshade and pigweeds (see full efficacy chart here https://mwveguide.org/uploads/pdfs/2021-herbicide-efficacy-table.pdf).

As always, choose fields with low weed pressure if possible and start with a relatively clean field either through stale seed bed or use of burn down herbicides (glyphosate, paraquat). Use pre-emergent herbicides followed by post emergent herbicides if necessary to get weed control further into the season, then mop up with spot sprays as needed. The full list of herbicide options can be found in the 2021 Midwest Vegetable Production Guide pg. 102 (https://mwveguide.org/uploads/pdfs/2021-cucurbit-crops.pdf).

Tony Dobbels discussing Reflex on pumpkins.

In July 2020, members of the department of Hort and Crop Science and IPM Program put out a small late summer herbicide weed screen trial at the Western Ag Research Station which was reported extensively in the 2020 virtual field day video segment starting at the 10:01 mark (https://u.osu.edu/jasinski.4/pumpkins/). In this 16 minute video, Reflex alone plus combinations of Reflex with Dual II Magnum, Sandea and Strategy are shown and discussed.

There is a Vegblog post on June 16, 2020 with additional comments about this herbicide concerning direct seeded and transplanted pumpkin and squash (https://u.osu.edu/vegnetnews/2020/06/16/whats-new-with-herbicides/).

Symptoms of herbicide injury.

Be sure to read the entire Reflex 24(c) label and understand the warnings about its use:
– Needs 0.5-1” rain or irrigation to be activated
– Sensitivity is possible on both pumpkin and squash hybrids – test on small area first
– Butternut is very sensitive to Reflex – test on small area first but expect thinning or yield reduction
– Cold and wet soils during germination and seedling growth may result in delayed maturity and / or yield.
– Heavy rain shortly after transplanting may also result in delayed maturity and / or yield.
– Reflex herbicide rates below 1 pt/A are not intended to be used as a stand-alone weed control program and should be used with other herbicides and/or other methods of weed control that support weed resistance management.
– Carryover injury possible and beware of rotation restrictions

The research and demonstration behind these new uses was paid for in part by the IR-4 Program, the Ohio Vegetable and Small Fruit Research and Development Program (OVSFRDP), and the IPM Program, and could not be conducted without the OARDC research stations and support from the chemical companies.

What plans are in store for 2021? We have another herbicide screening trial that will be rated for percent control of weeds and a hybrid sensitivity trial where we will look at potential seedling emergence and injury on pumpkin, squash and butternut as described by the label warning.

Midwest Vegetable Production Guide Now Available

If you are a vegetable grower in Ohio, the Midwest Vegetable Production Guide, is an essential resource to keep on top of the latest fertility, horticultural management, and pesticide recommendations for your operation. Each year the guide is edited and updated by specialist’s in eight states to bring you the most current information possible at the time of printing.

What’s new to the guide in 2020? Within the 262 spiral bound pages there is an updated Organic Production section plus updated sections on disease, weed and insect management on 45+ vegetable crops, from Asian vegetables to Zucchini.

The MVPG is also more mobile friendly now with an improved interface designed to get your crop production question addressed quickly. Enter your crop and pest information and receive cultural and pesticide recommendations matching your request. Try it out on your computer, tablet or smart phone at https://mwveguide.org. The site will default to the new interactive mobile friendly interface but if you want to access individual pdf chapters of the guide, click on the drop down and select “Production Guide.”

MVPG new and mobile friendly interface.

To get a traditional hard copy of the guide, contact your local Extension office and they can order a copy from main campus. Cost will be around $15.

MVPG cover for 2020. 

If you want to order a guide online through the new Extension publications website, here is the link https://extensionpubs.osu.edu/2020-midwest-vegetable-production-guide-for-commercial-growers/. If you order the guide online and have it mailed to your house, it will cost $21.25 plus shipping.

Be sure to purchase your guide soon, there are only 90 copies left in inventory at OSU! Best of luck for a productive season!

 

 

 

Biodegradable Mulch: Your Next Production Tool?

Vegetable extension-research personnel from Ohio, Kentucky, Tennessee, and Iowa met on October 5, 2018 to discuss ongoing work and to plan follow-up activities … all toward helping improve short- and long-term farm success. Biodegradable mulch (BDM) was among the most talked-about topics. Dr. Annette Wszelaki of the Univ. of Tennessee led the BDM discussion and she provides comments for VegNet readers below. Also, note that Dr. Wszelaki will expand on these comments and summarize the large amount of research that her and other teams in various states have been doing with BDM, including on commercial farms, at the OPGMA-led Ohio Produce Network Meeting in Dublin, OH in January-2019. That presentation will be an excellent opportunity to gain a thorough update on BDM and its possible place in your toolbox.

Comments and Photos by Dr. Annette Wszelaki, Professor and Commercial Vegetable Extension Specialist, Univ. of Tennessee

Plastic mulches provide many advantages for vegetable production, such as weed and disease management, earliness of harvest, increased yield and quality, and moisture retention. However, plastic mulch use is not without disadvantages, including the cost, labor and environmental issues associated with plastic mulch disposal. Biodegradable mulches (BDMs) offer a potential alternative if they can provide similar advantages to plastic mulch without the disadvantages.

BDMs can look similar to traditional polyethylene mulch (i.e., stretchy and black or white-on-black) or in the form of paper (brown or black, sometimes with creping to give it stretch). They can be laid with a standard mulch layer. BDM’s are designed to cover the soil during the production season, and then begin to degrade as harvest nears. At the end of the season, BDM’s can be tilled directly into the soil. There they will degrade into carbon dioxide, water, and the bacteria and fungi that eat them. The degradation rate varies depending on environmental conditions, but by spring, most remnants will have disappeared.

At the University of Tennessee, we have been working with BDM’s on a variety of crops (tomatoes, pumpkins, and peppers) for 10 years. We have found comparable yields and quality to traditional plastic mulch with these crops, but not all biodegradable mulches and crop responses are equal!

Want to learn more about biodegradable mulches? Come to the session Could biodegradable mulches replace plastic in your production system? at the 2019 Ohio Produce Network in Dublin, January 16-17, 2019. In the meantime, please contact Annette Wszelaki (annettew@utk.edu or 865.974.8332) or visit www.biodegradablemulch.org for more information. Many thanks to Jenny Moore, Jeff Martin, the East TN Ag Research and Education Center Farm Crew, and many students along the way for their contributions to this project.

Figure 1. Creped paper biodegradable mulch just after field laying.

Figure 2. Stockpile of polyethylene plastic mulch on a Tennessee tomato farm.

Figure 3. Biodegradable plastic mulch in the newly planted pepper field.