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.

This article was submitted by Dr. Erdal Ozkan
Dept. of Food, Agriculture and Biological Engineering

Pesticides need to be applied accurately and uniformly. Too little pesticide results in poor pest control and reduced yields, while too much injures the crop, wastes chemicals and money, and increases the risk of polluting the environment. Achieving satisfactory results from pesticides depends heavily on five major factors:

1. Positive identification of the pest.
2. Choosing the least persistent and lowest toxicity pesticide that will work.
3. Selecting the right equipment, particularly the right type and size of nozzle for the job.
4. Applying pesticides accurately at the right time.
5. Calibrating and maintaining equipment to make sure the amount recommended on the chemical label is applied.

Proper calibration is key.

Inspection of sprayers

Higher pesticide costs and new chemicals designed to be used in lower doses make accurate application more important than ever. There is no better time than early spring to take a closer look at your sprayer. Here are some of the things I would recommend you do this week if you don’t want to unexpectantly halt your spraying later in the season when you cannot afford delaying spraying and missing that most critical time to control weeds:

• First, if you need new or one other type of nozzles on the boom this year, do not delay purchasing new nozzles. Do it now.
• Double-check your sprayer for mechanical problems before you start using it. You won’t have time to do this when planting is in full swing.
• Clean the sprayer tank thoroughly and make sure all filters on the sprayer, especially the nozzle filters are clean.
• Clean spray nozzles to make sure they are not partially plugged. Check their flow rates, and replace the ones that are spraying more than 10 percent of the original output at a given spray pressure.
• Check the agitator in the tank to make sure it’s working properly. This is extremely important if you will be applying dry chemicals. Run water through the spray system to make sure everything is working properly.
• Always carry a spare, excellent quality pressure gage (glycerin filled) in your shop, and check the accuracy of the pressure gage on the sprayer compared to the reading you see on this spare pressure gage. Your rate controller will not know if your pressure gage is bad, and the flow rate of nozzles will be adjusted by the rate controller using the bad pressure gage.
• Once you are convinced that all sprayer parts are functioning properly, it is time to calibrate the sprayer.

Calibrate the sprayer

One can determine if the chemicals are applied at the proper rate (gallons per acre) only by carefully calibrating the sprayer. Calibration, perhaps more than anything else, will have a direct impact on achieving effective pest control and the cost of crop production. While applying too little pesticide may result in ineffective pest control, too much pesticide wastes money, may damage the crop and increases the potential risk of contaminating ground water and environment. Results of “Sprayer Calibration Clinics” I participated in Ohio a while back, and data from several other States show that only one out of three to four applicators are applying chemicals at a rate that is within 5 % (plus or minus) of their intended rate (an accuracy level recommended by USDA and EPA). For example, if your intended rate is 20 gallons per acre, the 5% tolerable difference will be 1 gallon (5% of 20). So, your actual application rate should be as close to 20 gpa as possible, but not outside the range of 19 to 21 gpa.

How do you calibrate the sprayer?

There are several ways to calibrate a sprayer. Regardless of which method you choose, you will end up measuring the nozzle flow rate (in ounces), and the actual travel speed in miles per hour to determine the actual chemical applied in gallons per acre. Once you determine the actual application rate, you should find out if the difference between the actual rate and the intended rate is greater than 5% of the intended rate (plus or minus). If the error is greater than the 5% tolerable error margin, you will need to reduce the error below 5% by doing one of three things: 1) Change the spraying pressure, 2) change the travel speed, and 3) change nozzles (get a different size) if the error cannot be reduced below 5% by making adjustments in either the pressure or the travel speed, or both.

It usually doesn’t take more than 30 minutes to calibrate a sprayer, and only three things are needed: a watch or smart phone to record the time when measuring the nozzle flow rate or the travel speed, a measuring tape, and a jar graduated in ounces. Please take a look at the Ohio State University Extension publication FABE-520 for an easy method for calibrating a boom-type sprayer.  Here is the URL for this publication:

http:// ohioline.osu.edu/factsheet/fabe-520

Pumpkins are a beloved fall crop ushering in all kinds of festive activities such as hayrides, fall festivals and agritainment events at local farms. When you include Halloween and Thanksgiving holidays into the mix, this iconic orb gets plenty of exposure across the state and provides much needed revenue when most other field vegetables are winding down.

But Ohio’s slice of the pumpkin pie has dramatically shrunk in recent years. From 2011-2015, acres planted averaged 6,680 compared to 2016-19 with an average of 3,840 A planted, a 42.3% loss in acres planted and production value according to the Ohio Annual Statistics Bulletin from 2011-20 (Figure 1).

Figure 1. Pumpkin statistics from 2011-2020.

So the question becomes, what caused the loss of nearly 3,000 acres of pumpkin in production years 2016-20? People I have asked about this offer explanations such as Ohio growers are increasingly importing cheap and widely available pumpkin fruit from other states or abroad, saving on production costs. I have also heard that growers may not be reporting their pumpkin acres accurately or at all on National Ag Statistic Surveys which could account for the drop in reported acreage, but likely not so much from 2015 to 2016-2020. Was there a market shift due to buyer demands or Food Quality and Protection Act leading to a mass exodus of growers, again not known.

If YOU have an idea for the loss of 3,000 A of pumpkins from Ohio production, please feel free to share it with me at Jasinski.4@osu.edu or call me at 937-772-6014.

If you prefer to leave a written comment of any length, here is an anonymous link where you cannot be identified if that is a concern you have.

https://osu.az1.qualtrics.com/jfe/form/SV_7P8aLZ5iihcBnE2

If any production issues are mentioned, I’ll be sure to follow up with additional articles in the VegNet Blog to address these.

Figure 1. Area shaded in orange is where brood X of the periodical cicada is expected to emerge in 2021 (from Periodical and “Dog-Day” Cicadas, OSU extension Fact Sheet ENT-58, by D. Shetlar and J. Andon, 2015;
https://ohioline.osu.edu/factsheet/ENT-58
).

In case you have been living underground for the past 17 years, take note of the map showing the impending mass emergence of billions of Brood X cicadas in central and southwestern Ohio (Figure 1).

There is also a useful timetable for when to expect the emergence, mating, oviposition and end of the Brood X cicadas (Figure 2). The whole process is temperature driven but should begin in April and be over by the end of June.

If you are primarily a vegetable grower, you can relax a bit as the cicada emergence will likely not affect or damage any crops but adults may randomly appear in a crop and serve as a noticeable and potentially loud contaminant.

Figure 2. Estimate for cicada stages and life cycle (source https://www.cicadamania.com).

For small fruit and tree fruit growers, there is a chance of damage to stems about ¼” in diameter due to cicada oviposition. Celeste Welty, OSU Dept. of Entomology,  wrote an excellent article for the Ohio Fruit Newsletter recently that covers chemical and cultural options (https://cpb-us-w2.wpmucdn.com/u.osu.edu/dist/b/28945/files/2021/03/OFN_FEB_2021-FINAL-V2.pdf).

For anyone with an interest in reporting locations of cicada emergence, there is an app called ‘Cicada Safari’ that is available for iOS and Android devices. It is interesting that most of the cicada broods do emerge as expected 17 years after the previous emergence, but if they are off-schedule, it is usually by 4 years, usually 4 years early. Excellent information about the biology and behavior of cicadas can be found at the cicada mania website: https://www.cicadamania.com/ . Other general information about cicadas can be found there too.

Last but not least, why not take advantage of this rare free protein and try cicadas in a variety of tasty snacks and meals!

1. https://www.cleveland.com/entertainment/2016/05/cicada_recipes_how_to_cook_the.html
2. https://www.bonappetit.com/uncategorized/article/how-to-cook-cicadas-according-to-3-richmond-va-chefs
3. https://www.nationalgeographic.com/animals/article/130515-cicadas-recipes-food-cooking-bugs-nation-animals

Bon appetite!

For over 100 years OSU Extension has delivered information to growers in the form of field days, workshops, conferences, newsletters, factsheets, guides, bulletins, etc. However, in the past decade there has been a shift in how people (including growers) search for and consume information. That newer method of information transfer is through the use of “how to” videos to show people how to do something or prepare for something, and it’s available free 24 hours a day, 365 days a year.

Partial screen shot of OSU IPM YouTube Video Library.

The OSU IPM Video Library on YouTube (https://go.osu.edu/osuipm) embraced this digital delivery trend and was launched in 2009. The site now has 81 videos on a variety of crops (pumpkin, sweet corn, carrots, strawberry, hops, field crops and coming soon apples) and a number of topics including identification, monitoring and management of traditional and invasive pests.

Videos are added throughout the year to these categories called playlists and new playlists are being created to house specific content such as apples. In the next month or two, new videos on squash vine borer and striped cucumber beetles on pumpkin will be released. Updated videos on monitoring brown marmorated stink bug and spotted lanternfly are also on this list.

This year in addition to shooting in our traditional video format, we intend to experiment with shorter (one minute long?) but more frequent (weekly?) videos, including some live streaming from the field; stay tuned for more details on that.

How can YOU participate in adding content to the video library? What kind of topics would YOU like to see added to the YouTube channel? You can either email me directly at Jasinski.4@osu.edu about specific topics or ideas you have or if you prefer to send them 100% anonymously, click on this link (https://osu.az1.qualtrics.com/jfe/form/SV_6RawJGD7g2Tj2bY) and leave your suggestion. One thing we always struggle with is how long to make the video. While we generally know that shorter is better, it can be challenging to convey the nuances of some pest management topics in shorter videos but we try!

We hope the content on the site is useful to your operation and our IPM Team is looking forward to your video suggestions. Remember, YOU put the You in YouTube!

The following sweet corn performance trial report was compiled by Mike Gastier (gastier.3@osu.edu), OSU Extension, Huron County; Matthew Hofelich (hofelich.4@osu.edu), OARDC, Fremont; and Allen Gahler (gahler.2@osu.edu), OSU Extension, Sandusky County.

Refer any questions or inquiries about this project directly to these authors.

Sweet corn hybrid trial.

Summary
Sweet corn is an important crop in both the fresh market and shipping market in North Central Ohio, where a significant percentage of Ohio vegetables are grown.  Many different varieties of sweet corn are grown by producers with fresh market roadside stands, and still others are grown for early, mid, and late season shipping and processing markets, meaning growers demand a diverse selection of sweet corn varieties and maturities.  Growers have indicated this diversity should focus on SH₂ varieties with different stages of maturity, and variance in other traits.  Many new varieties are becoming available to meet these grower demands, and this study sought to determine which ones would perform acceptably in Northern Ohio, and which would have the desired traits growers are seeking.  For this trial, 34 SH₂ varieties were grown in 4 replicated plots at the Ohio State University’s North Central Agricultural Research Station near Fremont, Ohio.

For the full report and results as a PDF, click here.

There are literally hundreds of commercially available pumpkin and squash hybrids on the market today. For the past 20 years we have tried show a small sample of what is available for growers to take a look at during our annual pumpkin field day. The primarily purpose of the trial is to evaluate disease resistance to powdery mildew but also for fruit size, shape, color and yield.  Although the field day was held virtually this year, here are some details about the trial including a group photo (Figure 1) plus individual statistics about each squash and pumpkin hybrid.

2020 Pumpkin and Squash Fruit Group Photo.

The trial was direct seeded on June 1 into plots 50’ long with a row spacing of 15’. The final seed spacing in each row was 3’ – 4’ allowing for 12 or 13 plants per plot. Strategy (4.5 pt/A) and Dual Magnum (1.3 pt/A) were applied for weed control pre-emerge on June 2. Later emerging weeds were removed from the plots throughout the season. Soil testing for P and K were sufficient in that field so only nitrogen was applied side-dressed at 65 lb N / A using liquid 28-0-0 on June 26. The plots were managed for powdery mildew upon first detection on July 27, with the first fungicide spray applied on July 29. Future sprays were alternated on a 7-10 day schedule with the last application on September 4. An early harvest occurred on Aug. 12 and 18 to accommodate the filming of the virtual pumpkin field day. It is important to underscore that because the harvest was conducted prior to all immature fruit sizing and maturing, the number of marketable fruit and therefore the estimated yield values are all below their full yield potential. For the fruit that were mature at harvest, the average weight should be fairly accurate under our trial conditions. Realize also that these hybrids planted in your spacing regime may have different results than this trial. Overall, the trial received 6.8 inches of rain from June 1 – September 1.

The hybrids are listed by their seed company, powdery mildew rating (none, PM tolerant, PM resistant) and days to maturity (Table 1). The same list is also shown with the range of fruit weight, average weight, number of marketable fruit, and estimated fruit and tonnage per acre (Table 2).

Table 1. Data related to hybrids in trial.

Table 2. Physical data associated with trial harvest.

* seed received and planted ca. 1 month later than other hybrids leading to immature fruit at harvest.
** calculated using 50ft row length with 15ft row centers.
*** missing plants in plot leading to fewer fruit and reduced yield.

For a more detailed review of the fruit and foliage, view the Virtual Pumpkin Field Day Video from 52:84-68:43.  You can also take a look at the hybrids using the 3D Field Scale Model. Click the play button and then anywhere on the model or use the shortcuts in the left hand pane.

A total of 61 people signed up for the 2020 Virtual Pumpkin Field Day which premiered last week on August 27. If you weren’t able to participate in the field day last week, you can still watch the whole program which is posted here: https://u.osu.edu/jasinski.4/pumpkins/.

Since this is our first time doing a video based field day, take 3 minutes and tell us what you learned, liked or didn’t like. https://www.surveymonkey.com/r/vpumpkin20impact.

Also on the main pumpkin page you will find additional pumpkin related resources including past reports on powdery mildew management, hybrid trial results and other information.

The pumpkin field day video has been viewed 74 times and is hosted on the OSU IPM YouTube channel https://go.osu.edu/osuipm.

OSU pumpkin page with lots of resources.