Month: June 2017

First 2017 Report of Cucumber Downy Mildew in Ohio

Downy mildew was confirmed this afternoon in cucumbers in West Salem (Wayne County), OH.  This follows a report of downy mildew on pickling cucumbers and cantaloupe in Essex County, Ontario yesterday, and is about 8 days earlier than our first Ohio report in 2016. Cucumber and melon growers throughout Ohio should intensify scouting, and these crops should be protected with effective fungicides. Cooler, wetter conditions the last week have been very favorable for downy mildew. In northern Oho counties, the downy mildew risk is high, so the more effective downy mildew fungicides Ranman 400SC and/or Orondis Opti A & B (co-pack) should be the core of the fungicide program.  Zing!, Gavel, Zampro or other fungicides (see table below) can be rotated into the program. A chlorothalanil (Bravo, Echo, Equus, Initiate) or mancozeb (Dithane, Manzate, Penncozeb) product should be tank mixed with the downy mildew fungicide.  Always rotate fungicides with different modes of action and follow label instructions. Remember that Orondis Opti A & B applications are restricted to 1/3 of the total fungicide applications.  We recommend applying the first Orondis application when the risk of downy mildew is highest. Under highly conducive environmental conditions, apply fungicides on a 5-7 day schedule.  When the risk is lower due to hot, dry, sunny weather, or downy mildew has not been reported in the area, the schedule may be stretched to 7-10 days. Cucumber and cantaloupe downy mildew risk is much higher in northern than in central and southern Ohio at this time.

Click on table to enlarge.

Vegetable insecticide update

Several more vegetable crops have been added to the list of crops on which Exirel and Verimark can be used. These contain the active ingredient cyantraniliprole, also known as Cyazypyr. This is in the same chemical group as Coragen and Altacor. The changes are summarized below. Full details are found on new supplemental labels.

Exirel is for foliar sprays, and can now be used on potatoes and other tuberous/corm vegetables; snap beans and other legume vegetables; radish, carrot, and other root vegetables; as well as on greenhouse-grown cucumbers. Crops already on the older federal label for Exirel are cabbage, kale, and other Brassica vegetables; green onion, bulb onion, and other bulb vegetables; cucumbers and other cucurbits; tomato, pepper, and other fruiting vegetables; lettuce and other leafy vegetables, as well as greenhouse-grown tomato, pepper, and eggplant. Target pests are caterpillars, aphids, flea beetles, whiteflies, leafminers, Colorado potato beetle, and thrips.

Verimark is for soil applications, and can now be used on green onion, bulb onion, and other bulb vegetables; snap beans and other legume vegetables; radish, carrot, and other root vegetables. Crops already on the older federal label for Verimark are cabbage, kale, and other Brassica vegetables; cucumbers and other cucurbits; tomato, pepper, and other fruiting vegetables; lettuce and other leafy vegetables; potatoes and other tuberous/corm vegetables. Target pests are caterpillars, leafminers, whiteflies, aphids, and thrips.

Belay has a new label that no longer includes several vegetable crops that were on the previous label. The new label also has some new restrictions. Belay is a neonicotinid that contains the active ingredient clothianidin. Growers who have existing stocks of the old product with the old label are allowed to use it as detailed on the old label, but all new product purchased this year will have the new label. Belay can no longer be used on tomato, pepper, eggplant, or other fruiting vegetables. Use of Belay on cucurbits and potato is still allowed, but with modified directions for use. On cucurbits, the previous label for foliar applications specified to not apply within 7 days of harvest; the new label does not specify a number of days, but that applications must not be made after the 4th true leaf on the main stem is unfolded. On potato, the pre-harvest interval remains as 14 days, but restrictions now include not applying treatment between 50% row closure and petal fall, and not making more than one application per year prior to 50% row closure.

News from the OSU Vegetable Disease Diagnostics Lab

It has been a busy week in the diagnostics lab – we continue to receive high tunnel and greenhouse tomatoes, but open-field vegetables and herbs are now making an appearance. These are some of the plant disease problems from around Ohio received this week.

Basil downy mildew – sporulation of pathogen Peronospora belbahrii on stem

Basil downy mildew. The sample from Ashland County had unusual sporulation on the stems (see photo). We normally find lesions on leaves with spores on the underside. This might indicate a systemic infection, possibly from seeds. See my post on May 4, 2017 for recommendations on management of this disease. Note: The basil downy mildew pathogen does not cause disease in cucurbits. We have not seen cucurbit downy mildew in Ohio or in the Great Lakes region yet this year.

Early symptoms of bacterial wilt on cucumber leaves – photo by F. Rotondo

Cucumber bacterial wilt. This disease was found in Highland County. Bacterial wilt can be a very serious problem in cucumbers, melon, squash and pumpkins, among other cucurbits. It is caused by a bacterial plant pathogen – Erwinia tracheiphila – that overwinters in striped and spotted cucumber beetles. When the beetles emerge from the soil they feed on cucurbit plants and transmit the bacteria to wounded tissue. We expect that beetle survival was higher than usual this year as a result of the mild winter of 2016/2017. The beetles can damage or kill young plants even in the absence of Erwinia, but if the bacteria enter the plant it is likely to die or at least perform poorly. The earlier plants are infected, the more likely they are to die quickly. Conventional growers can control bacterial wilt with appropriate insecticides – see the Midwest Vegetable Production Guide (pp. 122-123 in 2017 Guide) for recommendations. Options are limited for organic growers and gardeners, although row covers until flowering will protect plants when they are most vulnerable.

Brown longitudinal lesion and root rot of eggplant caused by southern blight; white mycelium of the pathogen Sclerotium rolfsii

Southern blight. We found this disease on young eggplant and pepper seedlings on OSU’s Waterman farm in Columbus. This is a disease that thrives under hot, moist conditions – it is not common in northern Ohio but we have seen it before in central and southern Ohio. An elongated brown lesion on the lower stem and root rot were accompanied by white mycelium (see photo), sometimes clearly in a fan shape, at the base of the stem. Small, round sclerotia eventually form on the surface and serve as overwintering structures. Sclerotia can survive many years in the soil, so it is important to remove diseased plants and accompanying sclerotia from the field.

Lesions of Septoria blight on tomato seedlings

Septoria blight of tomato. The disease was diagnosed tomatoes from Highland County. Typical symptoms are small necrotic spots on leaves, but not on fruit, which can help distinguish this disease from bacterial spot. Necrotic lesions caused by Septoria lycopersici contain tiny round black structures called pycnidia that can be seen with a hand lens. The pycnidia contain spores of the pathogen that are released when exposed to water. Therefore the disease is rare in greenhouses and high tunnels unless there is exposure to rainsplash or overhead irrigation. Septoria can be seedborne – we diagnosed Septoria blight in tomato transplants from a greenhouse with overhead irrigation earlier this spring in which infested seed was a likely source. Septoria blight is best managed with timely fungicide applications; a strobilurin fungicide should be included in the program.

Severe 2,4-D damage on tomato

Herbicide drift damage – high tunnel tomato. We have seen several cases of herbicide drift damage to tomatoes from high tunnels so far this season. When we receive samples that look like possible herbicide damage, we pass the sample on to OSU’s Dr. Doug Doohan. He diagnosed the sample pictured here as damage from exposure to the herbicide 2,4-D. This was a very severe case.

Corky root rot of tomato

Corky root rot of high tunnel tomato. This disease is often part of a soilborne disease complex of tomato that may also include Fusarium wilt, Verticillium wilt, black dot, and root knot nematode, among others. In this case, corky root rot was the primary problem. Like other soilborne diseases, corky root rot is very difficult to manage if resistant varieties are not available. Where the disease is a problem, grafting onto a corky root rot- resistant rootstock is very helpful in managing the disease. We are also working on anaerobic soil disinfestation (ASD) as a method of reducing populations of soilborne plant pathogens in high tunnels.

Many thanks to OSU Vegetable Pathology lab members Dr. Francesca Rotondo, Dr. Anna Testen and Claudio Vrisman for their work on these cases.

Celeryville Mourns the Passing of Jordon Holthouse

Jordan Holthouse of Holthouse Farms in Willard, Ohio passed away on June 21, 2017 at the age of 85. Jordon grew up on a vegetable farm in Willard then called Holthouse Brothers. He served military duty during the Korean War by serving in the U.S. Coast Guard as an electrician on the icebreaker Mackinaw. Jordon became a school teacher after the war and taught school for a few years until he rejoined his Dad on the farm in 1964. Soon two other brothers, Stanton and Mark joined the operation and the farm came to be known as Holthouse Farms.

The brothers worked hard to grow the business and to establish an operation that could outlive them and sustain generations to come. This was extremely important to Jordon. Today the Holthouse operation is ran by Jordon’s sons, Ken and Steve, and by Stanton’s sons, Kevin and Kirk. In 2003 Holthouse Farms acquired D.R. Walcher Farms in nearby North Fairfield, Ohio to expand the farms product line. 

Jordan has been active in the Holthouse operation until very recently. He was also active in the Celeryville Muck Crop Growers Association until last year. At the monthly breakfast meetings, when crop updates where given, Jordon was never sure of a crop until it was harvested, marketed and paid for. His experience told him that if everything in the operation is just fine, you probably hadn’t scouted crops yet that day. Jordon was a true voice of experience.

Jordon’s son Ken had this to say about his Dad:  “As we reflect on this life, most of what we always said about him is that he just liked to work. Work was his hobby. However, as we hear from people every day, we realize that his work was a way to connect and invest in people. It did not matter if you worked for him or with him or served on some committee. He did his best to contribute and did not ask for recognition”.

The life story of Jordon Holthouse closely mirrors the story of the Celeryville Muck Growers. Both stories were based on hard work, dedication, family, sustainable growth, striving to improve and giving back to the country and your fellow man.

We will miss Jordon, but his legacy will live on for generations.

-Mike Gastier, OSU Extension Educator, Huron County

The formal Holthouse obituary.

 

“Mr. Holthouse was a great inspiration for me as a Junior in high school to pursue my studies and degrees in in Horticulture from OSU with an emphasis on vegetable crops. I stopped by Mr. Holthouses office one late fall day and introduced myself  and told him  my interest in vegetable crops and he took time from his busy schedule to give me a tour of his farm and of the entire muck crops farming area and filled me in on the history of the area, his knowledge of vegetable crops was phenomenal. I believe this time I spent with Mr. Holthouse guide my career path to what it is today, he was a major contributor to the Ohio Vegetable industry.  

-Brad Bergefurd, OSU Extension, Horticulture Specialist, South Centers 

 

“Jordon’s accomplishments and service are known by many. I appreciated his direct and humble manner and his humor. He tended to liven up most all the conversations he was part of, especially with perfectly delivered and on-point one-liner quips. I recall one from a breakfast meeting long ago that brought lots of laughter: “there is no rest for the wicked and the righteous don’t need any.”

-Matt Kleinheinz, OSU Professor, OARDC Horticulture and Crop Sciences 

What’s Chewing on my Pumpkins and Squash?

By now, most pumpkin and squash growers have made it past the early season pests like cutworms and mice. Although cutworms show up only sporadically in cucurbits, they can cause lethal injury by cutting the stems of young pumpkin plants as they move off of weeds in the field, especially after a herbicide burn down. Field mice such as the white-footed mouse and the deer mouse, can also devastate plantings by digging up and eating seed, especially in no-till situations with a cover crop, such as winter rye. Once the seedlings have emerged, mice are rarely a threat.

Treated pumpkin seed dug up and eaten by field mice.

Black cutworm damage to seedling pumpkin plant.

 

 

 

 

 

 

 

Now that we are a little later in the season, we have other threats to be aware of, such as striped cucumber beetles and squash vine borer. Striped cucumber beetle adults can now be found congregating, sometimes en masse, on all types of cucurbits, including melons. The feeding damage can be severe enough to kill small seedlings, but just as important is the potential to spread bacterial wilt through wounds opened in the plant. Scout seedlings every few days, and if the threshold of beetles per plant is exceeded, then insecticide treatment is recommended. Take care to not spray insecticides when bees are active.

Thresholds are as follows:
Cotyledon-1st leaf, 0.5 beetles / plant
2nd-3rd leaf, 1 beetle / plant
4th leaf and older, 2 beetles / plant

Striped cucumber beetle feeding damage on pumpkin plant. Note beetle on leaf.

 

 

 

 

 

 

 

 

The adult of squash vine borer, a purple and orange moth, is also now flying around looking to lay eggs at the base of zucchini, squash, and pumpkin plants. Losses to this pest are usually not severe in most commercial plantings, but home gardens can suffer greater losses. A pheromone trap can be used to determine if SVB is active in your area. If moths are captured, consider applying 2-4 sprays 7-10 days apart to control this pest with foliar insecticides directed at the base of the stem.

Squash vine borer flying by stem of pumpkin plant.

Squash vine borer resting on pumpkin leaf.

 

 

 

 

 

 

 

 

 

 

 

 

 

For the most current pesticide recommendations, consult the 2017 Midwest Vegetable Production Guide (https://ag.purdue.edu/btny/midwest-vegetable-guide/Pages/default.aspx).

Bramble Harvester Demonstration

If you are interested in seeing how brambles are harvested mechanically for processing, consider attending the Stokes Berry Farm (2822 Center Road, Wilmington, Ohio 45177) on June 29th from 11am – 1 pm, weather pending. The bramble harvester will be on display and a demonstration of the harvester in action will be conducted. For more details, contact Dale Stokes at 937-382-4004.

Spotted Wing Drosophila Update – Jim Jasinski, IPM Program; Celeste Welty, Dept. of Entomology

Various OSU cooperators, mostly specialists and Extension educators, have been monitoring for spotted wing Drosophila (SWD) adults in a statewide network since around mid May. So far positive detections have been made in Franklin, Greene, Clinton, Clark, and Wayne counties, with an unconfirmed report from Champaign county. Several other counties in the SWD trapping network have not reported yet so this is what we know to date.

While the captures are still relatively low, they are higher than this time frame last year.

If you grow raspberries, blackberries, grapes, peaches, strawberries, or blueberries that have ripe or ripening fruit, you should be alert to any SWD reports in your area and be prepared to start a treatment program if found on your farm. Here is a quick SWD factsheet and insecticide list for your reference (https://u.osu.edu/pestmanagement/files/2017/04/SWD_Ohio_handoutV15-1fd4zp6.pdf).

Frame grab of latest SWD video explaining trap set up.

If you don’t have ripe or ripening fruit yet, it is still not too late to put a trap up and look for adult flies. A new 3 minute video showing how to set up the SWD trap we currently recommend, the Scentry trap, has just been created and posted on the OSU IPM YouTube channel at https://youtu.be/z9IeuYECnJk (Fig. 1). Remember that any SWD trap will catch non-target insects, so be sure to have your catches inspected for the right species. The Scentry trap and lure can be purchased at Great Lakes IPM (http://www.greatlakesipm.com).

Scouting – Harlequin bugs on broccoli

Hocking County had a serious problem last growing season with Harlequin bug damage on crucifers.  Any plant that was not monitored with hand picking or treated with insecticide was severely damaged up to complete loss of product.

Scouting started in mid-May with the first bugs noted at The Urban Farm on June 13th.

Feeding damage from the bugs is noted on the leaf in the form of white stippling. Large holes were caused by feeding of Cabbage White larvae

Hand picking was used to remove the several bugs noted instead of insecticide to allow harvest of the remaining broccoli.  The planting beds will be rotated out of broccoli within the next couple weeks and no other cruciferous vegetables will be planted until August, but scouting will continue.

Harlequin bug (Murgantia histrionica) –>  Profile: Journal of Integrated Pest Management

Factsheet: University of Maryland

OSU Vegnet photo identification

Monitor and Predict Conditions during Production, Storage, and Transport

Vegetable growers rely on an increasing diversity and quality of information to succeed. This information includes what the temperature, humidity, and other conditions around their crops have been, are, and are likely to be in the near future. Of course, past, current, and future weather conditions are hugely important to all growers. However, conditions in confined spaces at any point during crop production, storage, or transport also influence the farm’s bottom line. This article has three sections. Section 1 highlights grower-friendly pieces of equipment making it easy to monitor and, in some cases, record important conditions in fields, high tunnels, storages, sheds, trailers, vehicles, containers, and other locations nearly anytime. Section 2 references an online source of past growing condition data for various locations in Ohio. Section 3 includes a link to a site offering local forecasts for nearly any location in Ohio and the U.S.

Monitoring. Personal “weather stations” are increasingly reliable, durable, widely available, and lower-cost. Stations are rarely moved and are commonly placed in or near production areas. Stations that fit nearly any budget and interest are available from ag/forestry and other equipment suppliers. Costs hinge on variables monitored (number, frequency), data storage capability, quality of instrumentation, extent and type of connectivity, and expectations for maintenance. Upper-tier stations track and record temperature, relative humidity, wind speed and direction, barometric pressure, and rainfall. Simpler systems that monitor temperature and send data by text are popular with some growers (especially ones using high tunnels during spring and fall), or others wanting to monitor conditions in storages, packing sheds, and other areas. Not surprisingly, applications for ultra-small, battery-powered, durable, portable, and relatively inexpensive sensor-datalogger units measuring about 1.5-inch square are also increasing. Growers, distributors, shippers, buyers, and retailers — everyone in vegetable supply chains — look to document conditions surrounding crops or shipments from field to delivery and through display. Crop production researchers have long-used sensor-datalogger units to record temperature and humidity in soils and air in many plots simultaneously. People focused on post-harvest topics, such as conditions affecting crop condition in storage and transit, have done the same. As unit prices drop and questions about crops increase, people in supply chains look to temperature, humidity, and other data for partial answers. Individual sensor-datalogger units take and record readings often (e.g., every five minutes) and store data collected over periods lasting weeks, if needed. Data are downloaded to a laptop or uploaded to a personal website and imported directly to a worksheet.

I am often asked to help determine the cause(s) for various crop defects, all of which have cost the grower real money. More and more of these cases involve defects discovered after harvest, e.g., after delivery or transport. Also, the situations can involve a disagreement between grower and employee, shipper, or buyer, etc. regarding where the problem began. In all cases, some reliable record of the temperature and humidity surrounding the crop from harvest through delivery (and storage on-site, if used) would have helped the diagnostic process. Obtaining those records is easier and less expensive each year. Also, three complex challenges may intensify peoples’ interest in crop monitoring on the farm and past the farm gate: 1) spray drift, 2) maximally effective application of crop protectants, perhaps especially fungicides, and 3) food safety. Regarding weather monitoring and forecasting, personalization of the process has helped fuel https://www.wunderground.com/weatherstation/overview.asp and related groups.

Past Weather/Growing Conditions. The OSU-OARDC manages a set of weather stations (http://www.oardc.ohio-state.edu/weather1/) and daily or hourly data from the stations can be viewed/downloaded soon or long after they were recorded (e.g., http://www.oardc.ohio-state.edu/weather1/stationinfo.asp?id=12). Like all stations, the OARDC ones provide data specific to their location. So, the data should be used cautiously. Still, the stations provide numbers for important locations over many years.

Weather Forecasts. There is no shortage of weather forecasting services and apps and everyone has their favorite. I have come to appreciate being able to obtain current, multi-variable National Weather Service forecasts for nearly any location in the U.S. quickly and easily. The process outlined at https://www.weather.gov/wrn/hourly-weather-graph requires only a minute and a few mouseclicks or taps on the screen of your mobile device but no downloads. I have bookmarked several locations and can see forecasts for them quickly.

Hardin County Report – Early June

The heavy rains over the first weekend of June and low temperatures at night slowed things down. Strawberries were being harvested with lower than normal yield.  Strawberry prices were very good at the auction, and growers wished they had more available for sale.  Growers are cultivating and tying up tomato plants in their hoop houses.  There are a few tomatoes, cucumbers, and onions coming out of the hoop houses.  Pests of concern right now are cucumber beetles that are working on the vine crops.

Mark Badertscher – OSU Extension, Hardin County

Levi Yoder – Scioto Valley Produce Growers – contributor