Crop samples submitted to the OARDC Weed Lab (http://owl.osu.edu) with suspected herbicide drift injury symptoms sky-rocketed in 2017 and early indications are for the same trend in 2018.  This is happening mainly because vegetables and fruits are much more sensitive to the 2,4-D and dicamba herbicides grain farmers are now using to kill weeds that are no longer sensitive to glyphosate alone.  There is always some drift; but when crops have an elevated sensitivity to the compounds moving in the environment, everyone sees the effect.

Already in 2018, most grain fields have received burndown sprays containing 2,4-D (and some with dicamba) mixed with glyphosate. Predictably samples from injured fruit and vegetable fields, and orchards are being submitted for diagnosis.  So far, roughly 50% of the samples received are not showing symptoms characteristic of herbicide drift, and that’s significant because our lab rarely receives the samples until they have cleared a pathology screen.  So, while crop injury from drift is up significantly, there are still relatively few instances of damage where drift is clearly the culprit.

A general deterioration in farm community relationships has already occurred in some states, as a result of recent conflicts arising over drift.  Grain, vegetables, fruits, landscapes and natural ecosystems have been damaged sometimes with tragic consequences, following the expanded use of 2,4-D and dicamba. Human nature being as it is, we all tend to look outside to explain our problems before we look inward.  Considering this, it is important to consider other possible causes of crop injury before assuming occurrence of drift from the neighbors’ fields.

• Keep in mind that the injury symptoms associated with 2,4-D and dicamba are indirect responses of the plant to stress, and may have other causes. For example injury caused by glyphosate, used by most vegetable farmers, can sometimes resemble injury caused by 2,4-D.

• Volatile by-products of incomplete combustion (think of heating a greenhouse or high tunnel) are also known to cause symptoms on bedding plants not unlike those caused by herbicides.

• Inadequate decontamination of spray equipment used to apply glyphosate, 2,4-D or dicamba may leave behind trace amounts that are enough to cause injury in a subsequent application to a sensitive crop.

• Carryover of herbicides used on previous rotational crops, sometimes going back two growing seasons, may cause symptoms on vegetables that can be confused with those resulting from 2,4-D or glyphosate drift.

• Environmental conditions, in particular flooding during and after crop establishment, may induce symptoms that can be confused with herbicide injury, or they may exacerbate the effects of exposure to trace amounts of residual herbicides in the soil that would normally have no affect.

So, ‘what’s a farmer to do?’, to reduce the likelihood of being hurt by drift from nearby fields?

• Communicate! Talking with the neighbors is first and foremost. This can be difficult considering consolidation of grain farms and rental of land; but communication is vital in protecting your crops.  Explain that the crops you grow are very sensitive to herbicide drift, and that drift can result in a complete yield loss of a very high value harvest.

• Communicate! Sign up with the Ohio Sensitive Crop Registry.  Steve Smith, Director of Agriculture with the Red Gold Company, reports that incidents of tomato crop injury from drift have declined dramatically since they required their contract growers to register with the sister-program Field Watch (previously known as Drift Watch).  We know that most, if not all, commercial applicators check the Ohio Sensitive Crop Registry before going out to apply herbicides, so registering is clearly the cheapest (it is free) insurance available.

• Communicate! Steve also reports that placing “No Drift” signs along field edges helped tremendously.

• Pay attention to pesticide applications on nearby (and not so nearby) fields. Applications in early morning and evening are especially prone to inversion conditions that keep tiny droplets of spray suspended and prone to drift. It will be prudent to keep a written list of observed applications with date, time and observed conditions (are tree branches in motion, flags straight out, etc?). Photographs taken with a smart phone can be location, date and time stamped.

• Scout your fields at least every 2-3 days paying special attention to field edges where incoming drift will likely have the greatest effect. Symptoms of glyphosate injury usually take 3 + days to become apparent.  Symptoms of 2,4-D and dicamba can develop in less time, often within 24 hours, when growing conditions are ideal.

• If you see injury anywhere scout the entire field and the hedgerows. Look for patterns.  Drift usually leaves a path of injured weeds, shrubs and trees (look up) along the way. Trace the path to its apparent origin.

• Photos are very important but equally so, you need a written description of what each photo is attempting to illustrate and where it was taken. Photograph injured plants and plants that are healthy.  Check each photo to verify that it shows the symptom you are trying to capture.  If it doesn’t, take another in different light, from a different angle, or distance.

• Create a map of the field or mark an existing map, showing where photos were taken and outlining areas affected and not affected.

• Communicate! Talk to the neighbor, or the applicator if it was a commercial job. Explain that you have injury, that you have reason to suspect it was drift, and that you are monitoring the situation.  Ask them to identify what pesticides were applied.

• Maintain normal growing practices. If you seek a settlement you must have yield data, and if yields are lower than expected you do not want your failure to maintain the crop to be the reason.

• The decision to contact the ODA is personal, although an argument can be made that pesticide applications resulting in drift should always be reported. If you contact ODA there is no cost to you for their services, including their analysis of crop tissue for pesticide residues, but once you have contacted them be certain that they will conduct an investigation.

Thinking about the above points it should be obvious that maintaining high quality and complete field records, year in and year out, is important when drift occurs.  Being able to 1) substantiate your own crop and pest management practices validates that you were not the cause of the problem, and 2) past yield records from the field affected will help support a claim for lost yield.

Remember to communicate with your neighbors each year.  Keep in mind that many grain farmers have no idea how valuable an acre of produce can be.

Finally sign up with the Ohio Specialty Crop Register.  Past experience indicates this may be the single most important step you can take to protect yourself.

Cover crops have been used for decades on diversified vegetable farms.  Over the past 5-10 years there has been a resurgence in the use of cover crops as nutrient management, nutrient scavenging, and water quality have come under increasing scrutiny and focus.

Several researchers at OSU have conducted work on the use of cover crops in both field crop and specialty crop systems.  In 2005 and 2006, Andy Wyenandt (graduate student) and Dr. Mac Riedel (emeritus Dept. of Plant Pathology), worked on several cover crop combinations to determine which mixtures seemed to be the best fit for most pumpkin operations in Ohio. Based on the goals at the time to select a cover crop or mixture that persisted through the growing season and generated enough biomass to suppress weeds and soil borne diseases such as Fusarium, determined that fall seeded winter rye was one of the best options.

One unexpected outcome of this research overwhelmingly embraced by growers who adopted this management practice was how clean the fruit were at harvest, requiring little or no additional washing, especially during rainy autumn weather.  Later research focused on modifying a solid stand of winter rye using modified tillage to create more suitable planting or transplanting zones.  Now that soil building and ecology has becoming increasingly more important to growers, cover crop mixes are being used that go beyond just covering the soil, and seek to increase beneficial microbial activity in the soil.

On September 21, 2017, five cover crop mixtures were broadcast seeded and then worked into the soil using a cultimulcher at the Western Ag Research Station in South Charleston with the purpose of being used in a pumpkin seeding or transplanting demonstration in 2018. The cover crop mixes range from simple to diverse, with some of the same earlier goals to cover the soil, reduce weeds and diseases, keep the fruit clean, and enhance soil building and microbial activity.

The cover crop mixes were purchased through Walnut Creek Seeds. The species, ratios, seeding rate, and cost are as follows:

1. Scavenger mix (60 lb/A, $36/A) – 94% winter rye, 6% tillage radish
2. Nitro plus mix (60 lb A, $44/A) – 74% winter rye, 22% crimson clover, 4% nitro radish
3. Soil builder plus mix (50 lb/A, $56/A) – 60% winter rye, 20% crimson clover, 16% hairy vetch, 4% tillage radish
4. Nitro soil builder mix (60 lb/A, $88/A) – 30% winter rye, 27% winter barley, 17% crimson clover, 11% hairy vetch, 6% sun hemp, 3% tillage radish, 3% cabbage, 3% sunflower
5. Custom blend (58 lb/A, $197/A) – 34% crimson clover, 52% Pacific gold mustard, 14% tillage radish

Three-foot swaths of each 30’ plot were sprayed out with glyphosate on 15’ row spacing that will be rototilled for transplanting pumpkins in late May or early June. Images shown below are of initial seeding and growth in the fall, followed by growth in the spring as of May 7^th. Though some cover crop mixes listed up to eight plant species, most of them winter killed, leaving only winter rye, crimson clover, and hairy vetch seen growing in any of the plots.

There will be additional reports on this demonstration project as the season progresses, and it will be a stop during the pumpkin field day on August 23rd.

It’s that time of the year again when berry, grape, and peach growers throughout Ohio have to start thinking about Spotted wing Drosophila (SWD) on their farm.  Getting growers and Extension educators familiar with this pest, how to monitor, identify, manage, etc., has been a significant focus of faculty in the Dept. of Entomology and the Integrated Pest Management (IPM) Program.  So, in addition to hanging baited traps in your fields, take a few minutes to increase your SWD IQ by perusing the information and videos below.

To date, there have been six hands-on workshops held around the state over the past six years, two webinars and dozens of meetings where updates on current research have been given for the benefit of both growers and Extension educators.

In an effort to establish a greater online presence about various aspects of SWD management, a series of videos have been created and placed on the OSU IPM YouTube channel (https://go.osu.edu/osuipm) which can be accessed at anytime. The focus of each of these videos is briefly described below, and placed in order from deploying the trap in the field (first step) to conducting a salt water test (last step).

1. Complete SWD orientation webinar – In this video, all aspects of SWD are introduced including biology, damage, distribution, how to deploy and service traps, how to move trap contents (insects) to vials, how to sort through vial contents to identify male and female SWD, how to perform salt water tests, and finally an overview of chemical and non-chemical management strategies. This webinar contains three of the videos mentioned below; 1. How to transfer trap contents to a vial, 2. How to identify male and female SWD adults, and 3. How to conduct a salt water test on fruit. 82 minutes long; https://youtu.be/i8PlAoE1ob8

2. Setting up a spotted wing Drosophila Scentry trap including lure and drowning solution – In this video, you will be shown how to assemble a Scentry trap by adding a commercial lure and drowning solution. Considerations such as where to place in your field are discussed (edge vs. interior) and where in the crop canopy to place the trap to achieve optimal SWD catch conditions. 3 minutes; https://youtu.be/z9IeuYECnJk

3. How to rejuvenate an old SWD Scentry trap – In this video, you will be shown how to take an old faded Scentry SWD trap that has been used for several seasons and restore it to full functionality with some basic tools and a few common items, such as red duct tape, binder clips, pliers, and 14 gauge galvanized wire. 5 minutes; https://youtu.be/_DpL3H5v2ag

4. How to transfer SWD trap catch to a vial in the field – In this video, you will be shown how to transfer the contents of a SWD trap over to a vial for proper storage and later identification. Once the trap catch has been successfully moved to a vial, it can be securely transported to where the stereoscope or other high powered magnifier resides. The vial contents can then be emptied into a small dish for use under a microscope or other magnifier, where SWD adults and non-target insects can be sorted and identified. 5 minutes; https://youtu.be/emDu_FF1dB0

5. How to sort and identify Spotted Wing Drosophila adults using a stereoscope – In this video, you will be shown what tools and supplies are needed to transfer insect samples from a SWD trap or vial to a petri dish to begin the sorting and identification process. Both male and female SWD flies are sorted and identified in this video, which incorporates a live demonstration of the sorting process through the lens of a stereoscope. This is a very unique perspective and should give a very close “real world” experience of how to manage and sort samples. 6 minutes long; https://youtu.be/QDqvuIjLfu4

6. How to conduct a salt water test (Updated) – In this updated video, some recent tips were added to the overview of how to conduct a salt water test. This demonstration shows producer’s how to determine if fruit has been infested with SWD larvae, which is a reflection of their spray program efficacy. All the supplies needed plus images of the larvae (maggots) floating in the salt solution are shown. 6 minutes long; https://youtu.be/MtMXHxqcSVs

The SWD workshops, webinars, and video series have mainly been supported by USDA NIFA grants 20147000622507 and 20177000627174, while OSU’s overall SWD program have been funded by several sources including USDA NIFA and the Ohio Vegetable and Small Fruit Research and Development Program.