Cucurbit Downy Mildew – One Day Update

Cucumber downy mildew, Hardin County OH. Photo by Francesca Rotondo.

Just after posting yesterday, July 30 I received a confirmed report of downy mildew in cucumbers in Hardin County. See that post for recommendations.

Cucurbit downy mildew outbreaks in Ohio counties. Red color indicates reports less than 7 days ago. https://cdm.ipmpipe.org

 

Pumpkin Field Day – August 26

Pumpkin flower.

It’s been approximately 730.5 days (but who’s counting) since the last in person pumpkin field day was held at the Western Ag Research Station (7721 S. Charleston Pike, South Charleston, 45368), so be sure to mark your calendar for Aug. 26!

The field day will start promptly at 5:30PM and end at 7:30PM. After a brief wagon ride out to the research and demonstration area, both new and experienced growers will hear at least four talks:
-How climate and weather impact Ohio vegetable crops (Dr. Aaron Wilson, Extension/Byrd Polar Center);
-Weed management and Reflex herbicide trial results (Tony Dobbels, Horticulture & Crop Science);
-Jim Jasinski (Extension) will give a brief update on the powdery mildew fungicide trial and germ plasm hybrid trial.
-We also have a visiting scientist from Purdue University, Dr. Dan Egel (Plant Pathology) who will cover general disease management or other hot disease topics at that time.

To attend the event you need to pre-register by August 24:
https://osu.az1.qualtrics.com/jfe/form/SV_7WnQLmG3bcyQWc6

Even though the field day will be held outside we will still be following University Covid protocols which call for social distancing and possibly masks, so please come prepared. We will not be able to serve refreshments as we have done in the past so please bring your favorite beverage or water.

For more information on the event please see the attached flyer or contact Jim Jasinski (937-772-6014 or jasinski.4@osu.edu).

Pumpkin field day flyer

Insect Monitoring Network Highlights – July 3rd

As in prior years, Ohio State University has a network of traps set across the state to monitor key fruit and vegetable pests to help growers better manage these pests. These traps are checked weekly by state specialists, extension educators and some growers. Funding for the network comes from the OSU Extension IPM Program.

The trap data can be accessed here:
https://docs.google.com/spreadsheets/d/1KLU8rEoaz1Cnt9ILbUf77tSxOIriwZR0Xtj-wwNZgDA/edit?usp=sharing

Based on those cooperators who have reported numbers to date, here are some highlights to be aware of:

Spotted wing Drosophila are being detected in Brown, Greene and Geauga counties, so growers who have ripening or ripe small fruit (blueberries, raspberries, blackberries or strawberries), peaches or grapes, should be monitoring and ready to treat if just one SWD is detected. Treat through harvest to protect berries. More biology and treatment details can be found here: https://u.osu.edu/pestmanagement/pests/swd/

Corn earworm is a pest of several crops but is particularly attracted to silking sweet corn. Increasing CEW have been trapped in Clark, Sandusky, Seneca, Wayne and Putnam counties. The chart below provides a treatment schedule based on the number of moths and the peak temperature.

Corn earworm management chart.

European corn borer, another pest of sweet corn and peppers, has been detected in a few counties (Clark, Sandusky, Seneca and Wayne) but the numbers seem relatively low as the first generation of moths is declining.

 

Squash vine borer adult on pumpkin leaf.

For growers of cucurbit crops (pumpkin, squash, melons) there has been an upswing in Squash Vine Borer moths detected in Clark, Greene, Putnam and Lucas counties. If growers decide to treat, aim for the base of the plant and be aware of application restrictions if plants are flowering (for pollinator safety).

 

 

A few Spotted Lanternfly nymphs have been caught in circle traps around Mingo Junction in Jefferson county where they were first seen last year. Catching them in traps at this location was expected and ODA has plans to treat that area to prevent the spread. Remain vigilant for late instar nymphs which are red, black and white; soon to follow will be the adults which are capable of flight.

Erika Lyon’s photo of SLF nymph caught in trap.

3D printed Spotted Lanternfly (early nymph, late stage nymph, adult).

Custom Farming Rates

Farming is a complex business and many farmers utilize outside assistance for specific farm-related work. This option is appealing for tasks requiring specialized equipment or technical expertise. Often, having someone else with specialized tools perform a task is more cost-effective and saves time. Farm work completed by others is called “custom farm work” or more simply, “custom work.” A “custom rate” is the amount agreed upon by both parties to be paid by the custom work customer to the custom work provider.

This publication reports custom rates based on a statewide survey of 377 farmers, custom operators, farm managers, and landowners conducted in 2020. These rates, except where noted, include the implement and tractor if required, all variable machinery costs such as fuel, oil, lube, twine, etc., and the labor for the operation.

Ohio Custom Rates

Indiana Custom Rates

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” (https://ohioline.osu.edu/factsheet/fabe-527) -FABE-532, “Best Practices for Effective and Efficient Pesticide Application” (https://ohioline.osu.edu/factsheet/fabe-532).

Another excellent source of information on a wide range of topics related to pesticide application technology is http://sprayers101.com.

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

pumpkin

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.
https://youtu.be/KIHeMtkF98Y

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.
https://cpb-us-w2.wpmucdn.com/u.osu.edu/dist/1/8311/files/2021/05/OVSFRDP-final-report-Dec2020_Welty_v2.pdf

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 (https://youtu.be/RSzTT_gbma4) 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 (https://mwveguide.org/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 (ppdl-samples@groups.purdue.edu​ 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 (https://youtu.be/PVtY-c92ZdM).

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 (https://u.osu.edu/pestmanagement/pests/bmsb/). Additional information can be found at https://www.stopbmsb.org.

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.