Here are some commonsense practices for effective spraying of pesticides

This article was posted on behalf of Dr. Erdal Ozkan, Department of Food, Agricultural and Biological Engineering.

June is the start of a busy spraying season for vegetable growers. Paying attention to some key principles of spraying is likely to result in achieving your goal: maximum net return on expensive pesticides sprayed. Before giving you some specific recommendations on how to achieve the best results from pesticides sprayed, I want to remind you 6 key elements of successful spray application.  When applying pesticides, certain tasks are required for maximum biological efficacy. These include:

  1. Uniform mixing of pesticides (especially dry products) in the sprayer tank. This can be accomplished only if the agitation system in the tank has sufficient capacity for its size and is operating properly.
  2. Choosing a pump with sufficient capacity to deliver the required gallonage (gal/acre) to the nozzles.
  3. Ensuring hoses and fittings between the pump and nozzles are properly sized to minimize pressure losses.
  4. Ensuring minimum loss of pesticides as they are delivered from the nozzles to the target.
  5. Attaining maximum retention of droplets on the target (minimum rebound).
  6. Providing thorough and uniform coverage of the target with droplets carrying active ingredients.

Sprayer traveling over a vegetable field.

Here are just a few of the best spraying practices you may want to pay attention to get the most out of the pesticides sprayed:

  • Carefully read and follow the specific recommendations provided on the pesticide label, in nozzle manufacturers’ catalogs, and sprayer operator’s manuals.
  • Calibrate the sprayer to ensure the amount recommended on the label is applied.
  • Check the sprayer setup to ensure the amount applied is distributed evenly across the spray swath.
  • If more than one type of chemical is added to the sprayer tank, check product labels to ensure mixing is done in the appropriate order.
  • Conduct calibration of sprayer, mixing and loading of chemicals in areas without risk of ground/surface water pollution.
  • Operate the nozzles at a pressure that allows them to produce the spray quality (droplet size) recommended on the product label.
  • To achieve best coverage on the target, select the appropriate types of nozzles for the product, and if applicable (not restricted by the label) keep the spray volume (carrier application rate) above 15 gpa.
  • Follow recommendations to reduce spray drift to minimum. Probability of spray drift is much greater with some nozzles than others, and when nozzles are operated at a much higher pressure than they are designed for which forces them to increase the number of drift-prone small droplets discharged.
    • Slow down when spraying. Spray coverage is usually improved at slower speeds. Also, the higher the travel speed, the greater likelihood of spray drift.
  • For herbicide applications, flat-fan nozzles are better than cone nozzles which tend to produce a much smaller proportion of extremely small, drift- prone droplets. However, for fungicide and insecticide applications, you may still stick to cone nozzles, or flat-fan nozzles that generally produce no larger than medium size droplets (nozzle manufacturers provide droplet size data).
  • Good coverage of just the top of the canopy may be sufficient for adequate pest control with some products. However, both horizontal and vertical coverage of the plant may be necessary for other situations, such as disease and insects that may be hidden in lower parts of canopies.
  • Be careful when using twin nozzle/pattern technology for application of fungicides. Two nozzles or spray patterns angled (one forward, one backward), work better when the canopy is not dense and tall, or when the target is the upper part of the canopy. Use single flow pattern nozzles under dense canopy conditions when penetration of droplets into the lower parts of the spray canopy is desired.
  • If you are a large-scale vegetable grower, take advantage of technological advancements in spray technology, such as GPS, Pulse Width Modulation nozzles for selective and variable-rate spraying, and auto guidance systems.
  • Be safe. Wear protective clothing, goggles and rubber gloves, and respirators if required on the label, when calibrating the sprayer, doing the actual spraying, and cleaning the equipment.

Inspect all parts of the sprayer periodically throughout the season.

Of course there are equally important topics I did not mention here, including: general inspection of the sprayer, importance of proper product agitation in the sprayer tank, adequate size hoses and fittings, determining sprayer setup for acceptable application rate, selecting proper boom height based on nozzle angle and spray overlap, cleanliness and pH of water used to mix the products in the tank, proper cleaning of the sprayer tank, spray additives that can enhance product performance, and handling pesticide waste and empty containers. I will cover some of these topics in more detail in my future articles throughout the summer. However, as we get into the busy spraying season, I highly recommend you check two OSU extension publications for detailed discussions on the topics I covered and not covered in this article:

-FABE-527, “Best Management Practices for Boom Spraying” ( -FABE-532, “Best Practices for Effective and Efficient Pesticide Application” (

Another excellent source of information on a wide range of topics related to pesticide application technology is

Pumpkin Patch Notes (J. Jasinski and C. Welty)

Weed Control

Plots stakes delineate herbicide treatments.

Research and demonstration plots are slowly going in as rain dances across the experiment station in South Charleston. On Tuesday a herbicide screen featuring common products (Strategy, Sandea, Dual Magnum) plus various Reflex treatments were planted. According to the 24(c) label, Reflex is known to have potential phytotoxic reactions with some butternut and squash hybrids, so a sensitivity trial with four butternut squash hybrids, four squash hybrids and two pumpkin hybrids was also planted.  Both trials were sprayed on Wednesday, followed by 0.7 inch rain which should have activated all the pre-emerge herbicides. These trials will be rated for weed control and phytotoxicity several times in the next month.

Missing Pumpkin Acres – Partially Solved


Missing pumpkin acres?

On April 2, an article was posted on the OSU VegBlog that looked at the sudden drop of pumpkin acreage from 2015 (>6,000A) to 2016 (<4,000A). I gave a few ideas for the potential drop in acreage and asked growers if they had any thoughts on the matter. I received several email and phone calls about the subject, here is the summary of our discussion.

Imports: Pumpkins are being imported from other countries or other states more cheaply than they can be produced here in Ohio, so growers who couldn’t compete with the prices of imports got squeezed out of the business.

Buyers: Many buyers of large chain stores are shopping around for the lowest price possible which has strained traditional supplier relationships. As a result, fewer Ohio growers are willing or able to compete at the lowest possible price so they are not supplying these market needs.

Labor: It is getting more difficult to find the labor needed to plant, maintain and most importantly harvest and pack a pumpkin crop in a timely manner. This labor used to be local folks or high school kids but that is getting tougher to find, as is qualified migrant labor.

All of these factors and undoubtedly others have contributed to the loss of pumpkin acreage in Ohio. What remains most interesting is the confluence of these factors between 2015 and 2016 to generate a nearly 2,500A loss, which has still not rebounded five years later.

More Cucurbit Pests About to Get Active
A few weeks ago I mentioned options for controlling early season cucumber beetles and by extension, bacterial wilt. As we look past the beetle

Squash Vine Borer Video Released on OSU IPM YouTube Channel.

invasion, remain vigilant for squash bugs and squash vine borer. A new video describing how to identify, monitor and manage Squash Vine Borer has just released on the OSU IPM YouTube channel.

Additional points that could have been made in the video include:

-An alternative to shaking the insects from the trap top into the plastic bag is to have a spare top, so that the active bag can be stuffed into a freezer to kill the contents which makes sorting and identifying much easier.

-The trap bottom should be about one foot above the ground and the string that holds the lure needs to be taught across the bottom of the trap to maximize catch. Use of a thin wire to hold the lure will help prevent sagging. The traps and pheromone lure can be found at just about any insect trapping supply business such as Great Lakes IPM.

-For non-chemical management row covers may work better on some crops than others based on how quickly they flower. There is also the possibility of late planting and/or trap cropping as a means to avoid peak SVB flight provided it fits with your marketing plans.

-While some plants do succumb to SVB attack, many other plants infested with SVB larvae survive and continue to produce fruit.

-Here are the results of a 2020 SVB trial on zucchini conducted by Celeste Welty. This research was funded by the Ohio Vegetable Small Fruit Research and Development Program.

Early Season Cucurbit Pests – Cucumber Beetles & Bacterial Wilt

Striped cucumber beetle.

In the next 2-3 weeks, pumpkin, squash, melon and cucumber growers looking for an early crop will start direct seeding in the field or preparing seed flats for later transplanting out in the field. One of the perennial pest’s growers run into is the striped cucumber beetle which can attack seedling plants and chew them nearly to the ground. In addition to the physical damage the beetles can inflict, there is also a chance that some can transmit bacterial wilt to the plant which will prevent it from setting mature fruit.

A variety of control measures and tactics to manage cucumber beetles and bacterial wilt are reviewed in this recent video ( which includes methods to limit the impact of these early season treatments on pollinators.

Here is a quick review of the recommended options:

Cucumber beetle leaf feeding injury, be sure to scout cotyledons for damage.

  1. Plant fungicide only treated seed, scout fields frequently and treat with a foliar insecticide if the cucumber beetle threshold per plant is exceeded. Typically we think of 0.5 beetles per plant at the cotyledon stage or 1-2 beetles per plant at 1-4 leaf stage as general thresholds.
  2. Plant systemic insecticide treated seed (FarMore FI400) to control cucumber beetles for 2-3 weeks in the field after seedling emergence.
  3. Sow trays with fungicide only treated seeds in a greenhouse or high tunnel, then treat transplants with systemic insecticides on benchtop just prior to transplanting or drench transplants in the field using treated water. If using this technique do NOT use FarMore FI400 treated seed as it will not control cucumber beetles when transplanted but additional insecticide residue will be present in the pollen and nectar.
  4. Use systemic insecticide products in-furrow at planting time; this technique will produce the highest amounts of insecticide in the pollen and nectar of any of the options outlined above so use the lowest effective rate.

For more information on all the recommended foliar and systemic insecticides for cucurbit insect pests, consult the Midwest Vegetable Control Guide (

New Strawberry Disease in Ohio?

A new strawberry disease has been found in Indiana and researchers are looking fo

New strawberry disease symptoms on foliage.

r samples to determine the extent of the problem. The disease, caused by a species of the fungus Neopestaltiopsis, has been reported in several southeastern states and other countries where it causes leafspots, fruit spots and a plant decline. In Indiana, the disease has been reported to cause a leafspot (Figure 1) and a plant decline. This disease resembles Phomopsis and upon further investigation may ultimately turn out to be Phomopsis.

Researchers are asking commercial growers who believe that they may have observed the disease to contact the Purdue University Plant and Pest Diagnostic Clinic (​ or 765-494-7071). The PPDL will waive sample handling fees for these samples until the researchers obtain the desired number of samples for the survey. Updates will be posted to the Hotline and to the PPDL website. Samples from multiple strawberry varieties and different types of production fields (matted row, plasticulture, high tunnel) are encouraged.

Information required for each sample:

  1. Strawberry variety
  2. Growing method: Matted row or plasticulture
  3. Location (state and county) where grown
  4. Approximate date of planting or year of matted row culture.
  5. Symptoms observed: Leaf spot, fruit rot, crown rot, or a combination of these.

This research will attempt to determine where the disease exists in Indiana and how the disease may be controlled. Results of these studies will be reported here when completed. The North American Strawberry Growers Association is sponsoring this research.

Stink Bugs on My Mind…and Camera

Overwintering BMSB getting active inside house.

While sitting at my home office desk this rainy afternoon, an annoying BMSB adult started buzzing around my head, landed on the window and then flew to the door, a subtle reminder to write this brief article. Earlier this week I was able to get out and shoot a quick video about identifying, monitoring and managing Brown Marmorated Stink Bug (BMSB). If you are interested to learn the current details of how to trap for this pest, take a look at the final video on the OSU IPM YouTube channel (

Distribution of BMSB based on trapping network in 2019.

While BMSB has an appetite for most fruit and vegetable crops plus corn, soybean and other hosts, it generally has not developed into a significant pest in Ohio as in states further east and into the mid-Atlantic region.  Our efforts to monitor this pest over the years has evolved with new trap designs and aggregation lures. The results of our monitoring seem to suggest the pest is slowly increasingly in the central, southwest and eastern areas of the state.

Sticky panel trap with pheromone lure.

While BMSB is beginning to become active now, most of the damage can be expected in the summer months on green and ripe fruit. In August and September, BMSB becomes more mobile and is attracted to sticky panel traps baited with pheromone lures. Unfortunately, the only crop with a threshold using the sticky panel traps is apples. For each apple block (ca. 5A) place one baited sticky trap at the edge and one in the interior about 50m away; when either trap catches 4 or more BMSB adults or nymphs, a treatment may be justified. Since BMSB tends to be an edge pest, a perimeter spray may be an effective way to treat this pest instead of the entire orchard.

For other crops, place a trap at the field edge, interior of the field or near a wooded border that is adjacent to a crop field to get an early determination if BMSB is in the area. One of the goals of current BMSB research is to develop more thresholds for other crops to help guide management decisions. Until then growers will have to resort to frequent scouting for nymphs an adults of BMSB and several other pest stink bugs in their crops.

Dr. Celeste Welty has much more information related to identification, biocontrol, damage and treatment of BMSB on her website ( Additional information can be found at

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

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 (

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 ( 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 (

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.
sprayer calibration

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:


Can YOU Help Solve the Case of the Missing Pumpkin?

pumpkinPumpkins 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 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.

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

Heads Up on a Billion Heads Up!

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;

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


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 (

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: . 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!


Bon appetite!

IPM Video Library on YouTube

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 ( 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 about specific topics or ideas you have or if you prefer to send them 100% anonymously, click on this link ( 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!