Sunburned pumpkins by handle. Note even handle is burned on one side.

This title should seem familiar as a slight twist on the famous John Denver tune from 1971. With temperatures in the low to mid 90’s for at least three days last week across most of the state, fruit that were not properly covered in the canopy were placed at a higher risk for getting sunburned.

Downy mildew infested field with no leaf canopy.

Based on observations over several years, fruit that are cut off the vine tend to burn more readily than those that remain on the vine, likely a function of being able to evapotranpirate enough moisture to stave off burning. As clade 2 downy mildew was reported on August 13 (active on pumpkin/squash), fields that were not protected suffered almost 100% defoliation with 10-14 days. Amazingly this photo with near total canopy loss had nearly no detectable sun burned fruit despite several fruit actually being desiccated to the point where they were shriveling in the sun! If these fruit were cut off the vine, I would have expected significant rind burning to occur.

While there are a few “white washing” products on the market to spray on fruit in the field to prevent burning, they have not been investigated at OSU. The best prevention is a good canopy through harvest. The next best strategies though more labor intensive would be to cut and move fruit to a shaded location to cure naturally. If fruit are in a u-pick patch, moving them to distinct piles and covering with shade cloth may also be a possible solution.

Another pest that we are actively monitoring using clear sticky traps and pheromone lures is the Brown Marmorated Stink Bug. This stink bug is known to feed on vegetables, grain crops, small fruit and tree fruit.

BMSB adults on sticky trap

While we are actively monitoring for this pest in eight counties, Adams, Athens, Greene, Seneca and Wayne counties are seeing trap catch increases, mostly related to adults. Late stage nymphs and adults pose the biggest threat to tree crops like apples, with their damage resembling several other types of injury such as hail injury or bitter pit (stink bug surface injury (L), internal injury (R); Celeste Welty).

Stink bug injury on apple, courtesy of Celeste Welty

Soon these adults will migrate from the fields to structures to seek refuge from the cold temperatures as they attempt to over-winter. If you have lived in Ohio for the past few years, you are no doubt familiar with these large brown stink bugs that invade your home or office in the fall.

While we only have established thresholds for this pest in apples, these were established in the mid-Atlantic and have not been vetted in Ohio yet. We would expect these thresholds to work well in Ohio but research has not been conducted to confirm the results. Monitoring strategies for vegetables, grapes and small fruit can be found here: https://www.stopbmsb.org/managing-bmsb/management-by-crop/

The monitoring system in apples requires two traps, one placed at the edge of an apple block and one placed in the interior. When the cumulative weekly total of both trap catches exceeds 10 stink bugs, an alternate row middle spray for BMSB may be justified. The details are outlined in this article: https://www.stopbmsb.org/stopBMSB/assets/File/BMSB-in-Orchard-Crops-English.pdf

Although we are moving toward the end of the season for most small fruit producers, keep in mind that spotted-wing Drosophila populations remain high across the state where traps have been placed on farms. Because of their short life cycle and abundance of ripe fruit, expect these populations to increase up until the first significant frost/freeze event.

SWD larvae in fruit

For growers who have abandoned their small fruit plantings for this year, SWD adults can easily be seen buzzing around ripe fruit as they oviposit eggs beneath the soft skin. Evidence of infestation can be readily seen as soft juicy fruit are filled with white SWD larvae. Even for growers who have maintained a regular spray schedule to control this insect, SWD adults can still be detected flying around bramble and blueberry patches albeit in lower numbers.

Since the threshold for this pest is only one adult per trap, it is necessary to maintain a spray schedule as long as the farm intends to harvest fruit. Once the decision has been made to end harvest, the sprays can be halted.

Call for Ohio growers to participate in research.

Emily Justus is a PhD student at Purdue University working on documenting the use of insect resistant hybrids or varieties as part of an overall IPM strategy. If you have a few minutes to share your practices with her that would be very useful for her research program.

Calling all vegetable growers! Please help us learn about how you manage insect pests. I am an entomology graduate student at Purdue University and was awarded a grant from North Central Region – Sustainable Agriculture Research and Education program to investigate vegetable grower pest management strategies. My goal is to understand how vegetable growers in Ohio manage their insect pests and use of integrated pest management strategies such as resistant varieties. Responses from carrot, celery, parsley, celeriac and dill growers would be helpful but all are encouraged to respond. I hope that this work will help extension educators serve you better!

The survey (link below) should take less than 10 minutes to complete and you can enter to win a hard copy of the Midwest Vegetable production guide! Thanks so much for your help!

https://purdue.ca1.qualtrics.com/jfe/form/SV_a3RjIX30FMikubj

Brown Marmorated Stink Bugs
A few weeks ago we started trapping for Brown Marmorated Stink Bugs to catch their mid-season reproduction and movement toward preferred vegetable and fruit crops where they can feed and cause significant mid to late season injury. There were spikes of nymphs and a smaller surge of adults from the week before in Adams and Greene county, while Wayne, Lake and Huron counties remain at zero reported detections.

Spotted wing Drosophila
Catches of these insects in berry crops continue to be high in Greene and Geauga counties. With a treatment threshold of one adult per site, individual trap catches have ranged between 10 and 124 adults per week. Even with properly timed insecticide sprays and picking ripe fruit every two days if possible will not completely prevent damage to fruit, but it will be minimized. Berries must be protected until harvest is over or severe losses may be seen.

Corn Earworm

Corn earworm adults filled trap in two days.

For any mid to late season sweet corn, expect the next month or two to bring peak corn earworm flights from southern parts of the US, predominantly on storm fronts. Corn earworm populations have climbed this past week in Clark, Huron, and Lake counties and remain present in Wayne and Putnam counties. Zero CEW moths were reported trapped in Sandusky and Seneca counties.

Keys to successfully monitoring  CEW require the trap be placed at ear height near fresh silking corn and to change the pheromone lure every two weeks. Failure to do both will result in lower moths captured and a perceived lower threat of infestation leading to a wider spray interval and higher kernel damage and more caterpillars in the ears. In Clark county the trap total was 7 CEW for one week of captures with the trap emptied on 8/11 and moved to a new location about 1/4 mile away on the same farm near silking corn. The CEW trap was checked today (two days later) and captured several hundred moths (see picture at right).

European Corn Borer
This pest is still at low levels across the state according to our monitoring network, with Clark, Sandusky, Seneca, Wayne, Putnam and Wood counties reporting zero moths captured. Only Gauega and Huron counties have reported captures this past week (5 moths and 1 moth respectively). I was sent images of a bell pepper field in southern Ohio that had what appears to be a heavy infestation of corn borer caterpillars in the cap and stem of the fruit but no larvae or frass could be found in the fruit. As other crops begin to dry down, ECB will look for many other crops to lay eggs and cause potential feeding injury to the plant or fruit, so keep vigilant for that pest.

To see what other pests are doing, check out the OSU pest monitoring network at https://docs.google.com/spreadsheets/d/1KLU8rEoaz1Cnt9ILbUf77tSxOIriwZR0Xtj-wwNZgDA/edit?usp=sharing

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

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).

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.