Author: James Jasinski

Weather Update: Cool, Dry Weather Continues

This article was originally posted in the CORN newsletter, 2022-34, written by Aaron Wilson.

After making landfall as a destructive Category 4 storm with winds to 155 mph along the southwest coast of Florida last week and another landfall in the Carolinas, the remnants of Hurricane Ian skirted across our far southeastern counties over the weekend with generally light rain and gusty winds (Figure 1). Elsewhere, lake-effect rain showers earlier in the week impacted counties in the northeast, but much of the state was dry. Temperatures have been running 3-10°F below normal for the past 7 days as well. Cool temperatures are limiting impacts from an overall drying trend across much of western and southern Ohio, but this is a good environment to continue drying crops ahead of harvest. The situation should be monitored in the coming weeks though for the potetnial for field and combine fires as the forecast indicates continued dry condtions. For the latest up-to-date conditions, seasonal outlooks, and monthly climate summaries, please visit the State Climate Office of Ohio.

Figure 1). Total precipitation over the period September 27- October 3, 2022. Figure courtesy of the Midwestern Regional Climate Center (https://mrcc.purdue.edu).

Figure 1). Total precipitation over the period September 27- October 3, 2022. Figure courtesy of the Midwestern Regional Climate Center (https://mrcc.purdue.edu).

Forecast
High pressure will keep fair skies and calm winds locked over the state for Tuesday through Thursday. After a chilly start in the 30s on Tuesday morning with scattered frost, temperatures will moderate throughout the week with highs in the mid to upper 60s (north) to mid to upper 70s (south). A series of cold fronts will sweep through late in the week with spotty showers possible on Friday. Cooler air will filter into the state with highs on Friday and Saturday only likely to reach the upper 40s to mid 50s, with overnight lows well down into the low to mid 30s. This raises the possability of some areas of Ohio (e.g., NW and NE) reaching their first fall freeze conditions (temperatures < 32°F); though at this time, upper 20s are not likely. For more informaton on historical fall freeze conditions, check out October Usually Brings Our First Fall Freeze also in this week’s C.O.R.N. Newsletter.

The Weather Prediction Center is forecasting less than 0.10 of an inch of precipitation in Ohio this week (Figure 2).

Figure 2). Precipitation forecast from the Weather Prediction Center for 8pm Monday October 3 – 8pm Monday October 10, 2022.

Figure 2). Precipitation forecast from the Weather Prediction Center for 8pm Monday October 3 – 8pm Monday October 10, 2022.

The Climate Prediction Center’s 6–10-day outlook for the period of October 9 – 13, 2022 and the 16-Day Rainfall Outlook from NOAA/NWS/Ohio River Forecast Centershow temperatures and precipitation are leaning toward below normal levels (Figure 3). Climate averages include a high-temperature range of 68-72°F, a low-temperature range of 46-50°F, and average weekly total precipitation of about 0.70 inches.

Figure 3) Climate Prediction Center 6-10 Day Outlook valid for October 9 – 13, 2022, for left) temperatures and right) precipitation. Colors represent the probability of below, normal, or above normal conditions.

Figure 3) Climate Prediction Center 6-10 Day Outlook valid for October 9 – 13, 2022, for left) temperatures and right) precipitation. Colors represent the probability of below, normal, or above normal conditions.

October Usually Brings Our First Fall Freeze

The article below was originally posted in the CORN newsletter, 2022-34, written by Aaron Wilson and Eric Richer.

The calendar has turned to October, and with it, harvest and fall activities will accelerate over the next few weeks. We have already experienced a few chilly nights this past week with patchy frost in some areas, but when do we typically see our first freeze conditions? This first (last) official freeze is defined as the first fall (spring) day where the overnight low reaches 32°F.

The Midwest Regional Climate Center (MRCC) has developed a new Freeze Date Tool (https://mrcc.purdue.edu/freeze/freezedatetool.html) that relies on historical temperature data at the county level back to 1950 and allows users to select a freeze temperature threshold between 20°F and 40°F to visualize the earliest, average, and latest fall or spring event. For instance, many of us are interested in the hard freeze threshold of 28°F, the temperature at which our corn and soybean growing season comes to an end.

Figure 1 shows the average first fall freeze date for areas of the eastern corn belt for the period 1950-2021 using the 32°F threshold. The online version allows users to hover their mouse over a county of choice to view the average freeze date for that county. For instance, the Knox County average is October 8, October 11 in Darke and Fulton Counties, and October 17 in Fayette County. Areas near bigger cities like Cleveland and Cincinnati have first freeze dates closer to the end of the month.

Figure 1: Average first fall freeze (32°F) for the period 1950-2021. Figure courtesy of the Midwest Regional Climate Center.

Temperatures are expected to flirt with 32°F on Tuesday morning and again Saturday and Sunday mornings. Still, most of the earliest dates and even the earliest 10% of dates on record occurred in late September, so we are beyond those thresholds. More recent first freeze dates have been occurring later in the year, with some counties reporting a trend of more than 3 days later per decade (~21 days later over the full period). The Freeze Tool also allows users to view these trends as well as more detailed analysis for individual counties.

Other MRCC climate related tools are available with cli-MATE. For instance, Figure 2 shows the probability of an earlier freeze in the fall for the Wauseon Water Plant in Fulton County using data over the last 30 years. Note that 50% of the time, a hard freeze (28°F) occurs by October 30th (green line) for this site. These graphs can be generated for stations across the state.

Figure 2: Probabilities of an earlier freeze in the fall for five temperature thresholds for the Wauseon Water Plant in Fulton, County Ohio. Figure courtesy of the Midwestern Regional Climate Center.

Reminder – Pumpkin and Sunflower Field Day – August 25

For over 20 years The Ohio State University has held a pumpkin field day as a source of production and pest management information for both new and experienced growers. This year we will be adding some flair as we begin to tackle the production and pest management issues surrounding the popular trend of sunflower fields for photography and cut flowers as an additional source of revenue on diversified farms. For growers who want to learn about two popular fall attractions, pumpkins and sunflowers, this is a field day that can’t be missed.

Pumpkin and sunflower

The field day will be divided roughly in half, with the first hour focused on sunflower topics ranging from grower experiences in production (Matt Sullivan, grower) to impacts from the ag tourism perspective (Kate Hornyak, OSU). A nine-hybrid sunflower demo strip trial will be in various stages of bloom for attendees to walk through and examine.

The second hour will focus on pumpkin production and pest management, with presentations on managing pollinators in cucurbits (Ashley Leach, OSU), foliar fertilizers and plant nutrition (Bryan Reed, Sunrise), a review of powdery mildew fungicide management followed by a walk through the 24 pumpkin and squash hybrid trial (Jim Jasinski, OSU).

The field day will be held August 25 at the Western Ag Research Station, 7721 S. Charleston Pike, South Charleston Ohio. The field day will begin promptly at 5:30 PM and end at 7:30 PM. Pre-registration is required for attendance and there is a $5 charge per person for handouts and refreshments (and likely a few sunflowers).

Pre-register by Aug. 23 at this link: https://go.osu.edu/pumpsun22

More details are listed on the attached flyer.
Pumpkin and Sunflower 2022 Flyer

Alert – Corn Earworm Moth Numbers Running Very High!

On the heels of the VegNet blog article posted a few days ago (https://u.osu.edu/vegnetnews/2022/08/13/corn-earworm-flight-numbers-spike/), corn earworm flights continue to be very high in southwest Ohio. In the past 10 days, over 1,000 moths have been trapped at the research station in South Charleston, including 424 moths caught from Friday (12th) through Monday (15th).

This pile is what 424 CEW moths looks like.

The Hartstack trap (large metal mesh) used at the research station is placed near fresh silking sweet corn which is very attractive to CEW moths and known to catch more moths than a Heliothis trap (white plastic mesh). Be sure to use the CEW management chart, which is based on the Heliothis trap, when making management decisions. Traps placed away from fresh silking corn will not catch as many moths.

These large moth flights have yet to be recorded in the northern county tier of traps in the network (https://u.osu.edu/jasinski.4/pestvisualization/#linke). Growers who are running Hartstack or Heliothis type traps to manage their insecticide spray intervals are advised to check their traps every few days for the next few weeks.

CEW flights in monitoring network.

Corn Earworm Flight Numbers Spike

Clark County has reported a massive spike in corn earworm (CEW) this week.

386 CEW moths caught during past week.

Other trapping locations have not reported an increase in activity yet (https://u.osu.edu/jasinski.4/pestvisualization/#linke). This annual caterpillar pest of sweet corn and tomato should have growers paying special attention to these crops for infestation, especially during the latter part of the season. Flights of CEW typically increase through the summer as the moth migrates into Ohio from southern states such as Louisiana, Texas and Mississippi. The caterpillar stage is known to attack silking corn and tomato fruit, especially when other susceptible hosts are not abundant.

CEW, aka tomato fruitworm, feeding on tomato.

Moths prefer to lay eggs on fresh sweetcorn silk and can hatch and enter the ear tip as quickly as two days under ideal weather conditions, where they are no longer susceptible to insecticide treatments. Treatments for this pest should be made based on number of moths per day and daily temperature threshold of 80F. Use the chart below to determine the recommended number of days between insecticide application to protect sweet corn as it enters silking. Insecticide options can be found in the Midwest Vegetable Production Guide, remember to rotate insecticide classes to avoid resistance (https://mwveguide.org).

CEW spray interval chart.

Want to learn more about monitoring for CEW? Check out this original video that reviews how to set up a trap to monitor for CEW (https://www.youtube.com/watch?v=W6b7OtUOo8Y&list=PL0HRPaZDLHyG53DPisl9iGTezcx815u-q&index=8).

There is also an updated version of how to monitor for several key moths in sweet corn on the OSU IPM YouTube channel https://youtu.be/X1jvQxx_fpc

Pumpkin and Sunflower Field Day – August 25

For over 20 years the pumpkin field day has been a source of production and pest management information for both new and experienced growers. This year we will be adding some flair as we begin to tackle the production and pest management issues surrounding the popular trend of sunflower fields for photographs and cut flowers as an additional source of revenue on diversified farms. So if you want to learn about two popular fall attractions, pumpkins and sunflowers, this is a field day that can’t be missed.

Pumpkin and sunflower

The field day will be divided roughly in half, with the first hour focused on sunflower topics ranging from grower experiences in production (Matt Sullivan, grower) to impacts from the ag tourism perspective (Kate Hornyak, OSU). A nine-hybrid sunflower demo strip trial will be in various stages of bloom for attendees to walk through and examine.

The second hour will focus on pumpkins, starting off with managing pollinators in cucurbits (Ashley Leach, OSU), foliar fertilizers and plant nutrition (Bryan Reed, Sunrise) and then a review of powdery mildew fungicide management and a walk through the 24 hybrid trial (Jim Jasinski, OSU).

The field day will be held at the Western Ag Research Station, 7721 S. Charleston Pike, South Charleston Ohio. The field day will begin promptly at 5:30 PM and end at 7:30 PM. Pre-registration is required for attendance and there is a $5 charge per person for handouts and refreshments (and likely a few sunflowers). For more information contact Jim Jasinski, Jasinski.4@osu.edu.

Pre-register at this link: https://go.osu.edu/pumpsun22

More details are listed on the attached flyer. Hope to see you there!

Pumpkin and Sunflower 2022 Flyer

Attack of the Killer Tomato (Hornworms)

Yes, this is the title of a 1978 comedy horror film (sans the hornworm part, that was added to provide context to the article).  I have a small garden at home and last week I noticed foliage and fruit chewed along with fairly large frass pellets laying around so I had all the clues needed that hornworms had indeed found at least two of my tomato plants. I began searching diligently but could only find one hornworm, I’m sure there were several more hidden among the foliage digesting their lunch.

Finding these worms at home made me think about scouting the much larger tomato research project at the Western Ag Research Station in South Charleston. Unfortunately, there is no pheromone trap to detect the moth so periodic monitoring of the plants for feeding damage or caterpillars is required. I started looking at the plants and soon discovered there were hornworms infesting about 5% of the plants.

Hornworm damage to tomato plant

 

Hornworm damage

While there are many types of hornworm moths, commonly referred to as hawkmoths or sphingid moths, there are only two economically important species found in Ohio that feed on tomato plants, the tomato and tobacco hornworm. The key characteristic I use to identify these two species is the shape of the markings on the side of the caterpillar; the tomato hornworm has a sideways “V” called a chevron on each segment while the tobacco hornworm has a slanted white slash that looks like a cigarette (to me). There are other characters to separate the species such as the color of the “horn” on the last segment (black vs. red) but these tend to be less reliable. The tobacco hornworm is usually more common in Ohio tomato fields than the tomato hornworm. The length of the worms found at the research station was up to 3 inches, which is near their maximum size.

Tobacco hornworm, note white slashes on segments

 

Tomato hornworm, note “V” shape on segments

Hornworms are often found with many small white cocoons stuck on their body. The cocoons show that biological control by natural enemies is in progress. A hornworm covered with cocoons has been parasitized by Cotesia congregata, a small braconid wasp. By the time the cocoons emerge from the larva, the hornworm is close to death and will not reach its pupal stage. One wasp will emerge from each cocoon.

Parasitized hornworm

The threshold for treating this pest is two or more hornworms or fresh damage per 40 plants scouted of any stage, from seedling to fruiting. Whether parasitoid cocoons are seen or not, the chances of biocontrol contributing to the management of this pest are increased greatly by avoiding the use of broad-spectrum insecticides. The best insecticide to use is one of the BTs such as Dipel or Javelin or Xentari, especially if worms are small. If insect pests in addition to hornworns are found in the tomato field, then conventional insecticides will be needed; most insecticides are very toxic to hornworms so the selection of the product should be based on the other pest(s). Products such as carbamates (Lannate, Sevin) and pyrethroids (Asana, Baythroid, Pounce, Warrior) are toxic to hornworms but disruptive to natural enemies like the Cotesia parasitoid. Products such as Radiant, Intrepid, or Neemix are toxic to hornworms but have a more gentle impact on beneficial insects. More insecticide options are listed in the Midwest Vegetable Production Guide (https://mwveguide.org).

Part of this article was excerpted from a previous VegNet article posted in 2009.

Spotted Wing Drosophila Spotted

Spotted-wing Drosophila (SWD) is one of the major pests of cane berries, blueberries, black berries, strawberries and peaches. Last week it was detected in Greene, Monroe, Geauga and Wayne counties but likely is present and active in most Ohio counties at this point in the season (https://u.osu.edu/jasinski.4/pestvisualization/#linki).

Spotted wing Drosophila male (L) and female (R).

Recall that this pest is relatively new to Ohio, first discovered in 2011, and has the distinction from other drosophila flies of being able to attack whole, healthy fruit as they begin to blush and ripen.

The best way to monitor for this pest on your farm is to use a trap with either a commercial lure or apple cider vinegar as a bait.

Spotted wing drosophila baited Scentry trap.

If you do this, it will be necessary to empty the trap weekly and look through the catch to identify the male (with the spot on its wing) or female (which has an enlarged serrated ovipositor) using a stereoscope. Remember that the threshold for this pest is 1 SWD fly, male or female. Once the threshold is exceeded, trapping can be halted. This can be a fairly intensive endeavor but has been described in detail in various videos posted to the OSU IPM YouTube channel (setting up trap, identification, salt water tests, etc.). https://www.youtube.com/playlist?list=PL0HRPaZDLHyFqKGmNic832l0SWqMO8IQ4

If you choose not to monitor for this pest and have had SWD on your farm before, it is nearly 100% certain they will return once fruit is in the blush or ripe stage, so you should prepare to manage based on their assumed presence. A fact sheet on SWD giving more detail on management and biology with an up to date list of insecticides can be found here: https://cpb-us-w2.wpmucdn.com/u.osu.edu/dist/1/8311/files/2020/11/SWD_Ohio_handout_V20.pdf

Once you decide to stop harvesting in a certain block, insecticide treatment for SWD can be halted. For smaller or organic growers, some cultural methods including use of black mulch, pruning and netting have been shown to reduce and delay infestation.

Medina County grower talking about his exclusion netting project to manage SWD.

Notes from the Pumpkin Patch – June 26

The seasonal pattern of too wet to do any field work has relented to extremely dry conditions given the past week of temperatures in the 90’s. I managed to get caught up on planting the last of my trials, side dressing those trials with emerged plants and applying herbicides in anticipation of rain.

Perhaps the biggest pest to note over the past week was Squash Vine Borer becoming active in Greene and Coshocton counties (https://u.osu.edu/jasinski.4/pestvisualization/#linkj). This pest can cause some plant loss if active in fields (egg laid on stem, hatches into caterpillar which bore into the plant stem and can no longer be successfully treated) but usually not more than five percent of plants are infested. In prior years I have seen losses up to 30% in some of my research plots.

Squash vine borer adult on pumpkin leaf.

One way to determine if this pest is active near your field is to observe a large purple and orange moth flying around the field, but the best way is to use a pheromone trap. Once increases in trap catches are seen, 2-3 applications toward the base of the plant every 7-10 days is an effective control measure. Foliar insecticide options are listed in the Midwest Vegetable Production Guide (https://mwveguide.org/guide). I produced a short video on monitoring and treatment options as an overview on the OSU IPM YouTube site (https://youtu.be/KIHeMtkF98Y).

SVB pheromone trap.

Not much other pest activity to note at the research station but it was obvious to see while working around the various trials which hybrids had been treated with FarMore FI400 and which ones were not based on their Striped cucumber beetle feeding levels. I also saw my first Spotted cucumber beetle of the season this past week.

Spotted cucumber beetle.

Spotted cucumber beetle.

Keep an eye out for the third major early season pest, Squash bug, which should be making an appearance soon.

Squash bug adult.

Squash bug eggs.

Early Season Notes from the Pumpkin Patch

Between the end of May and first 10 days of June, getting trials planted has been challenging with showers just about every 3 days. Typical field work ahead of direct seeding or transplanting (tillage or burn down) into our research and demonstration plots at South Charleston was definitely a “hurry up to wait” scenario. Hopefully most of you are having better luck at getting these crops in the ground!

As soon as I did manage to get some seeds and plants in the ground, there were quite a few pests waiting to pounce; read on and find out who!

Striped cucumber beetle – This is a pest that we expect to find every season. While it was reported several weeks ago in Southern Ohio, it made an appearance this past week in South Charleston. Notice the characteristic feeding damage on the lower cotyledon surface and on some of the early leaves. If FarMore FI400 seed was used not much damage should be expected but for untreated plants, scouting every few days while seedlings is important, followed by foliar sprays if beetles go over threshold (0.5 – 1 beetle / plant). Foliar insecticide options for all pests can be found in the Midwest Vegetable Production Guide (https://mwveguide.org/guide).

Striped cucumber beetles in a semi-dead state beneath FarMore FI400 treated plant.

Characteristic striped cucumber beetle feeding

Salt Marsh caterpillar – A sporadic pest that is primarily a foliage feeder. While feeding can be fairly severe, typically very few plants are affected. The injury looks similar to that of striped cucumber beetle feeding shown above.

caterpillar

Salt marsh caterpillar found on feeding on pumpkin transplant

Black cutworm – Another sporadic pest found especially in no-till fields where winter annuals such as chickweed and other weeds are present during seeding or transplanting. If a burndown herbicide is applied or other disturbance to the field is made, these caterpillars will move to and feed on fresh plants, including pumpkin or squash seedlings. The damage is characteristic cutting of the stem at the soil line and often the cut stem and leaves will be pulled into the soil. To find the cutworm caterpillar, lightly dig around the cut plant to find and destroy the pest or risk other seedlings being cut.

stem cut

Partially cut seedling stem

cut stem and caterpillar

Fully cut stem and caterpillar

close up of cut stem, leaf feeding and caterpillar

Close up of cut stem, leaf feeding and caterpillar

Field mice and voles – In reduced tillage situations or fields planted with cover crops, there is an increased risk of depredation by several species of mice and voles which can feed on a variety of plant parts including leaves, stems, roots and seeds of plants. They have a particular fondness for pumpkin and squash seed, and can move down a planted row systematically digging up and eating every seed for stretches up to 50 feet. Even newly emerged seedlings aren’t safe from feeding as the cotyledons and radical (main root) can be chewed off, killing the plant.

In every direct seeded trial at the research station this year, we have lost between 30 to 95% of stand due to seed feeding, so this is a major consideration for us to decide if a trial gets direct seeded or transplanted. For growers, the size of the operation and effort to raise transplant needs to be evaluated against the expense and time lost to replanting (7-10 days) which can affect marketing and field harvest, possibly impacting sales.

There are a few ways to minimize mouse and vole seed and seedling depredation including increasing field tillage to disturb nesting areas, reducing the rate of cover crop planted to provide less cover for these vertebrates and providing perching structures near the field to invite raptors to prey on these pests. Planting in warm soils will promote faster germination and limit the time seed is vulnerable to depredation.

The only approved chemical treatment is an in-furrow application of zinc phosphide pellets. This is a Restricted Use Product and is not allowed to be broadcast on the field.

Seed feeding

Seed feeding

Cotyledon feeding

Cotyledon feeding

mouse

Vertebrate pest