Jim Jasinski (Extension), Ashley Leach (Entomology)

It’s been cool and wet in most of Ohio slowing most planting schedules but cucurbit planting is poised to hit it’s stride toward the end of May through mid-June. This means growers need to be on the lookout for the primary early season pest of pumpkin, squash, melons, cucumbers and zucchini, the striped cucumber beetle.

Striped cucumber beetle adult.

These adult beetles are overwintering now but will begin actively searching for cucurbit seedlings to feed on, sometimes inflicting severe enough damage to outright kill plants. Recall that while seedlings can survive and outgrow minor beetle damage, it is key to avoid severe damage to seedlings in order to prevent bacterial wilt transmission while the plants are most susceptible, typically prior to the 3-4 leaf stage. Bacterial wilt infected plants will become symptomatic once there is high demand to translocate water from the roots to the shoots, such as the time of fruit enlargement. No treatments are available to reduce bacterial wilt once a plant is infected.

Bacterial wilt infected plant in foreground, healthy plant in background.

Scouting newly emerged cucurbit plantings every few days is essential to determine if enough beetles or damage is occurring to warrant treatment. Action thresholds vary from 0.5 – 1 beetle per plant for cotyledon and 1^st leaf stage seedlings to 1-2 beetles per plant for 3-4 leaf stage seedlings. Scout about 50 plants in both edge and interior areas throughout the field, flipping over leaves and especially looking under cotyledons to accurately determine beetle pressure and damage.

Severely damage cotyledon by striped cucumber beetle feeding.

Foliar insecticide recommendations for all cucurbit crops can be found in the Midwest Vegetable Production Guide (https://mwveguide.org/uploads/pdfs/Cucurbit-Crops.pdf).

To prepare for the arrival of striped cucumber beetles, consider reviewing a short but detailed video of several management options (beetles/plant thresholds, systemic seed treatment, use of transplants and in-furrow application) posted to the OSU IPM YouTube channel (https://youtu.be/RSzTT_gbma4).

A quick word about using insecticides to manage early season beetle populations. Based on your farm history with damage from this pest, field size, time of direct seeding or transplanting, you may not experience peak beetle pressure and can manage this pest by frequently scouting seedlings and treating if over threshold, the old fashioned IPM method!

If you purchased systemic insecticide coated seed (FarMore FI 400) which is very effective at controlling beetles, as evidenced by the pile of dead cucumber beetles on and near the treated plant, be aware that trace residues will accumulate in the pollen and nectar. If foraging honey bees, bumble bees, squash bees and other pollinators collect these food resources they may not be outright killed but more subtle sub-lethal effects on brood such as reduced feeding, fewer wax cells constructed, fewer eggs laid and other effects might occur. So, decisions about pesticide selection, pest severity, timing and non-target impacts should be considered before use.

Dead cucumber beetles at base of systemic insecticide treated plant. Courtesy of Celeste Welty.

If using FarMore FI 400 treated seed to raise transplants, do not treat them again with a systemic insecticide product during field setting as this will increase the residues found in pollen and nectar. If applying systemic products in-furrow, using the lowest labeled rate will still provide great beetle control for 2-3 weeks.

Jim Jasinski (OSU Extension), Chia Lin & Reed Johnson (OSU Entomology), Hongmei Li-Byarlay (Central State University)

Brassica cover crops like mustard (Brassica juncea) and rapeseed (Brassica napus) can be a good fit in some production systems, providing a range of benefits such as soil health, soil biofumigation and pollinator health.

Blooming mustard crop.

Recently it was reported that the natural biocides (glucosinolate compounds) produced by mustard plants could mitigate infections of Nosema (a fungal parasite) in honey bee colonies.  If glucosinolates are present in mustard pollen, mustard blossoms may provide the dual benefits of food source and disease control for honey bees.

To test that hypothesis, a two-year multi-site research project led by Dr. Chia Lin was recently funded to look at the effects of spring (mid-April) and late summer (late July) planted mustard as a cover crop to provide abundant pollen to foraging bees in order to measure specific effects on colony health. Both lab and field studies will be used to identify how much mustard pollen is collected by the bees and beneficial aspects of the targeted mustard planting on reducing Nosema impact on honey bees and improving winter survival of bee colonies.  Stay tuned for updates on this project.

Mustard cover crop emerging from one of the research sites.

Have you visited your vegetable field lately and come back disappointed because you were met with wilted, drooping plants? You are not alone. Recently, we have had an uptick in reports of maggot damage in vegetable crops. The insect culprits in question are most likely either onion maggot, seedcorn maggot or cabbage maggot. These maggots are very similar, and even belong to the same fly genus, Delia. These cream-colored maggots are small (0.5-1.5 cm) and have between 3-5 generations per year. These fly species will overwinter as pupae in the soil and emerge as adult the following year to find suitable host plants. Maggot will feed on seedlings and either kill the plant before it can successfully mature or injure the plant, thus giving entry to soil pathogens (secondary infections). This past season, you may have noticed more damage from maggots than normal. And that’s not surprising; maggot damage is typically greater in cool, wet seasons and in fields with high organic soil types.

There are some differences between these species that may point to one being the cause over another. Onion maggots love alliums, and are most problematic in onion, garlic, and leek. Cabbage maggot has an affinity for brassica crops including cabbage, cauliflower, Brussel sprouts, and turnips. Seed corn maggots love just about everything and can be found in as many as 40 different plant hosts. Notable crop hosts for seed corn maggot include soybeans, corn, beans, peas, cucumber, melon, pepper, potato, and even onion. As a general rule, seedcorn maggots typically damage the seed, whereas onion/cabbage maggots often feed on seedling roots.

The bad news is that if you are facing maggot damage there is little you can do to “rescue” your planting. Your best bet is to wait it out and replant if possible. You can drench with Diazinon (Diazinon AG500), but this product won’t ultimately save you from the damage that has already been afflicted. If you decide to use this product, make sure you use enough water. Diazinon doesn’t move easily through the soil and is best applied with adequate water.

Avoid “chasing” adult flies. You may see adult flies (figure 1) in your field but using foliar insecticides to kill adult flies is not an effective option for any species. Keep in mind the damage is in the soil, so make sure you target your management decisions to strategies that will protect the below-ground tissues of the plant (I.e., seed treatments or in-furrow applications at planting/transplanting).

If you are dealing with maggot damage on your farm, consider some of the options below.

1. Prevention is key. If you know you have a history of either seed corn maggot or onion maggot, make sure you take action by preventing an infestation before it starts.
   • Rotate your crop. Flies will show up when they know food is available. So do your best to confuse the flies by rotating your crops, especially alliums and brassicas. If you want to limit future infestations, consider planting a non-host crop to decrease the likelihood of subsequent maggot problems. If you are rotating your crop to a non-host, make sure you rogue out any volunteers from the previous year. (Maggots love volunteers!)
   • Use a seed treatment (Table 1). Insecticide treated seed is one of the most effective tactics to manage maggot populations. A number of efficacious products are available including thiamethoxam+ spinosad (FarMore FI500), cyromazine (TRIGARD), and clothianidin and imidacloprid (SEPRESTO) for many vegetable seeds (table 1). Rotate products between years so you are not exposing multiple generations to the same active ingredient. For example, if you are using FarMore in year 1, rotate to a different seed treatment like Trigard or Sepresto in year 2. WHY DOES THIS MATTER? Reports from the Northeast and MidAtlantic suggest that some maggot populations may become resistant to these seed treatments.
     

     Table 1: seed treatment options to manage  maggot infestations in vegetables. Please note that efficacy of these products may differ based on maggot infestation and/or soil type.
     Product	OMRI listed?	Active ingredient	Relative control of maggot	IRAC codes
     FarMore FI500	No.	thiamethoxam+ spinosad	Excellent.	4A, 5
     Trigard OMC	No.	cyromazine	Excellent.	17
     Sepresto 75 WS	No.	clothianidin+ imidacloprid	Good.	4A, 4A
     Regard SC	Yes.	spinosad	Excellent/Good.	5

2. Exclude flies from the crop. One viable management approach is to keep female flies from finding your crop. You can isolate your crop either in space (row cover) or time (degree day modeling).
   • Consider using row covering over your susceptible crops to stop adult oviposition (egg-laying). Multiple studies have found that this is a highly effective method at limiting damage.
   • Avoid maggot damage altogether by planting later in the season to bypass peak infestation. Maggots have predictable phenological patterns, and you can use degree day models to accurately predict times in the season when maggot risk is high. The first peak of seedcorn maggot occurs earliest in the season when 200 degree days has been accumulated, followed by cabbage maggot (250 degree days) and then onion maggot (250-300 degree days).
3. Monitor, monitor, monitor. While there is little you can do to manage maggot infestations within the immediate growing season, it’s important to identify problem areas so you can plan accordingly for the following year.
   • The best way to tell if you have Delia maggots on your farm is to scout early and often. Fields with poor plant emergence or wilted seedlings (figure 1, video) should be inspected for maggot damage. Make sure you cull any infested plants.

We are in the process of reevaluating and determining the monitoring needs of fruit and vegetable growers in the state. For awhile now, OSU extension educators and specialists have monitored for specialty crop pests.  We know there are a lot of different crops in Ohio and many different insect pests, but we’d like to know which pests are the most important to monitor.  This survey should only take 5 minutes and your thoughts and opinions are very important to us.

Click here for the survey link.

Thank you,

Ashley Leach and Jim Jasinski

Ohio State University Extension is seeking applicants for our next Assistant Director, Agriculture and Natural Resources. The Assistant Director is responsible for the leadership of Ohio State University Extension’s Agriculture and Natural Resources program area. This includes overall direction of educational programming within and across Ohio’s 88 counties. The summary of duties is listed below and a complete listing of the position description can be found at https://osu.wd1.myworkdayjobs.com/OSUCareers/job/Columbus-Campus/Assistant-Director–Extension-Agriculture-and-Natural-Resources–Associate-or-Full-Professor_R74003.

The Assistant Director reports to the Director of OSU Extension and serves as a member of OSU Extension’s Administrative Cabinet. Specifically, the Assistant Director provides leadership and direction for Agriculture and Natural Resources programming with emphasis on program and curriculum development; applied research; identifying potential collaboration and partnerships with universities, colleges, departments, peer agencies and industry partners; securing funding to support related activities; administrative leadership for the state Extension Agriculture and Natural Resources  office; and professional development of faculty and staff.

Education Required:  an earned Master’s Degree required, Ph.D. preferred, in an agriculture or natural resources related field.

Faculty Position (1.0 FTE)

Posting number: R74003

Location:  Statewide and Columbus based

Deadline Date:  April 30, 2023

Questions about the position can be directed to:

Elizabeth Hawkins, Field Specialist, Agronomic Systems

(937)286-4849, Hawkins.301@osu.edu

The deadline to register for the 2023 Small Farm Conference is quickly approaching.  If you haven’t registered for this great event yet, you still have time, as registration is open until March 3rd.

Follow this link for session descriptions, conference details and registration http://go.osu.edu/2023osusmallfarmconf

We hope to see you there.

Greetings the OSU Extension – Small Farm Team is excited to announce that the registration for the 2023 Small Farm Conference is open.  We hope to see you all there.

Ohio State Extension announced plans to host a Small Farm Conference in Mansfield Ohio on March 11, 2023.  The theme for this year’s Mid-Ohio Small Farm Conference is “Sowing Seeds for Success.”

Conference session topics are geared to beginning and small farm owners as well as to farms looking to diversify their operation.  There will be five different conference tracks including: Farm Office, Horticulture and Produce Production, Livestock, Agritourism/ Marketing, Natural Resources.

Some conference topic highlights include: How to purchase our family farm, food animal processing, bee keeping, sweet corn, blueberry and pumpkin production, small ruminant nutrition, agritourism laws, fruit tree pruning and cut flower diseases.

Anyone interested in developing, growing or diversifying their small farm is invited to attend including market gardeners, farmers market vendors, and anyone interested in small farm living.

Attendees will have the opportunity to browse a trade show featuring the newest and most innovative ideas and services for their farming operation. The conference provides an opportunity to talk with the vendors and network with others.

The Conference will take place from 8:30 a.m. – 3:00 p.m. at the Mansfield OSU Campus in Ovalwood Hall, just minutes from I-71 and US Rt 30.

For conference and registration call OSU Extension Morrow County 419-947-1070, or OSU Extension Knox County 740-397-0401.

Please follow this link for conference details and to register: https://go.osu.edu/2023osusmallfarmconf

Growers of organic produce or those interested in organic varieties and production are welcome to join the Ohio Organic Farmer Researcher Network for their monthly online meeting on Thursday, January 5 at noon. We have selected a small but varied panel of Ohio produce professionals to discuss their variety selection process and priorities, some of their best and worst experiences, and how their choices relate to marketing, labor, and other concerns. Panelist Q&A will be followed by farmer-led discussion about what motivates us to choose certain seeds varieties and how we decide where/how to source them. The primary focus will be on organic vegetable varieties that perform well in Ohio.

Connection details are available at https://offer.osu.edu/events/organic-farmer-researcher-network-january-meeting. Sign up for reminders and future meeting notices by emailing Cassy Brown.

The Ohio Organic Farmer Researcher Network is a growing group of organic and transitioning farmers, agricultural professionals, and researchers who meet regularly to discuss emerging issues, possible projects, and recent or ongoing research. Our group’s organization is a cooperative effort of OEFFA, Ohio State, and Central State universities.

Farmers, educators, researchers, and other interested individuals are welcome to join us on the first Thursday of each month to discuss a variety of topics related to organic production research.

Researchers at Purdue University and the College of Wooster are requesting responses from vegetable growers in the Great Lakes and Mid-Atlantic regions to learn more about their insect pest management practices to help direct pest management research and extension programs in specialty crop production!

QR code to participate in survey

Spotted-wing Drosophila is an invasive pest Ohio strawberry, peach, bramble and blue berry growers have been forced to deal with since 2011. This SWD team webinar will review the most recent information and tools for managing this pest. See details below.

We are excited to announce the 2022 SCRI NIFA Spotted-Wing Drosophila Management Team Webinar on Thursday, December 8^th, 2022 at 12:00pm EST. This one hour webinar, titled “Advances in Behavior-Based Tactics for Management of Spotted-Wing Drosophila” will focus on behavioral control with a brief update on biological control. Researchers will present recent findings as well as highlight recent advancements in behavior-based strategies to control spotted-wing drosophila.

To register for this webinar, please follow this link: https://zoom.us/webinar/register/WN_WSqvqIkESmWY0Lv_p40Oig

SWD webinar details