DSU High Tunnel Workshop & Field Day

Thursday, May 29, 2014   10:00 a.m. – 3:00 p.m.
Delaware State University
Smyrna Outreach Center
884 Smyrna-Leipsic Road
Smyrna, DE

Delaware State University will be having a High Tunnel Workshop and Field Day. The featured speaker will be Dr. Lewis W. Jett, who is the State Extension Vegetables and small fruit Crops Specialist, West Virginia University and a leading expert in high tunnels and season extension.

Talk Topics:
• Scheduling takeover crops (2nd warm season crop)

• Growing into the fall: what works and what doesn’t

• Heat management in the high tunnel

• IPM in High tunnels

• High tunnel production economics

Attendees will earn 1 Delaware pesticide recertification credit.

For more information, to register for this free workshop (lunch included), or for assistance due to disabilities contact:
Dr. Rose Ogutu at
rogutu@desu.edu or

Jason Challades at
jchallandes@desu.edu or 302-388-2241

Registration is open until May 22, 2014.

Click for High Tunnel Workshop & Field Day flyer.

Soybean Cyst Nematode Distribution Update

Nathan Kleczewski, Extension Specialist – Plant Pathology; nkleczew@udel.edu

Soybean Cyst Nematode Distribution Update

The 2014 SCN distribution was released earlier this year (Figure 1). For those of you who did not see this when I posted it on my blog in January, here it is again. No new news in the Mid-Atlantic, but some more counties have been confirmed in Virginia. Overall, you will see SCN has spread westward since 2008 (Figure 2). Maps are assembled by the SCN management working group.


Figure 1. The distribution of Soybean Cyst Nematode as of January, 2014.



Figure 2. The distribution of Soybean Cyst Nematode in 2008.

New Fact Sheets on Field Crop Disease Management

Nathan Kleczewski, Extension Specialist – Plant Pathology; nkleczew@udel.edu

Although the field crops disease page has yet to be launched due to a revamping of our webpages across the college, I have posted several new factsheets on field crop diseases, which are available on the University of Delaware Extension Website http://extension.udel.edu/factsheet/. The following can be currently found under the “Field Crops” heading.

Frogeye Leaf Spot on Soybean
Gray Leaf Spot on Corn
Stalk Rots on Corn
Anthracnose Leaf Blight and Stalk Rot of Corn

Hard copies of these factsheets will be available at your county extension office at the end of the month. Other factsheets on SDS and Fusarium Head Blight will be posted shortly. Additional factsheets will be posted throughout the growing season to help you with management of field crops diseases.

Time to Sign Up for Fusarium Head Blight Prediction Center Updates

Nathan Kleczewski, Extension Specialist – Plant Pathology; nkleczew@udel.edu

Fusarium head blight (FHB) epidemics are episodic, but when they do occur they can cause significant reductions in quality and yield. FHB will continue to be an issue for small grains due to corn production and the widespread use of conservation tillage. Thus, this disease, which historically caused few, localized outbreaks every 15-20 years now is seen more frequently across much larger areas. FHB should be on your radar if you are planting small grains. Current research indicates that suppression of FHB is achieved by using 1) a moderately resistant variety; 2) a recommended triazole fungicide applied at Feekes 10.5.1 or 4-5 days after Feekes 10.5.1; and 3) planting wheat following soybean. None of these practices used alone will provide sufficient suppression of FHB in a disease favorable year and must be integrated to maximize their suppressive effects.

Obviously rotation choices and variety selection are things that occur prior to the planting. However, the use of a fungicide is a within-season decision. One tool available to growers is the Fusarium head scab prediction website: http://www.wheatscab.psu.edu/. The website accurately predicts FHB outbreaks of >10% field severity roughly 80% of the time. Based on a current survey, the use of the website and its alert system has saved producers of small grains over $170 million.

How can you use this site? First, sign up for updates. Extension plant pathologists provide updates throughout the growing season. In Delaware I will be providing weekly updates until the crop starts to approach flowering, and every 3-4 days thereafter. Second, understand how to use the website. It is best to check the forecast around noon as this will allow the most current environmental data to be included into the forecast. The map will generate colors that indicate the level of risk for flowering wheat. Green = low risk; yellow = moderate risk; red = high risk (Figure 1). Thus, if your region is red, indicating high risk for FHB, but your crop is at boot, a fungicide application directed for suppression of FHB is not recommended. One weakness of the model is that it does not do a great job at predicting severe outbreaks during cool, wet conditions. Remember, anything above 60°F is sufficient for FHB as long as it is wet enough as wheat approaches flowering and there is a source of inoculum in the region (i.e. fields with small grains or corn residue). To account for this I suggest keeping a close eye on the commentary and local forecasts. Remember, the website is a tool to help you make informed management decisions but it is not an answer. Use all available resources when deciding to make fungicide applications to your wheat.

Another site I suggest you visit is ScabSmart: http://www.scabsmart.org/graincr.html. This is a great site with excellent information on FHB management. Lastly, sign up for updates from my Field Crops Disease Management Blog for alerts on diseases including FHB throughout the growing season: http://extension.udel.edu/fieldcropdisease/. I also post articles on important and new research, resources, and recommendations. This week’s blog entry is Fungicide use in Small Grains

FHB2013mapFigure 1. An example of the FHB prediction website map during the FHB epidemic of 2013. Flowering wheat in yellow and red were at risk for FHB infection at this point in time.

There is no way to know if 2014 will be another FHB favorable year.  The aforementioned resources will help keep you informed of potential outbreaks in the future.

Finish Wheat Fertilization Right Away

Richard Taylor, Extension Agronomist; rtaylor@udel.edu

With the onset of somewhat warmer temperatures, winter wheat is beginning to advance in its stage of development rapidly. At least in northern Delaware, many wheat fields appear to be between Feeke’s growth stage 5, leaf sheaths lengthened and erect, and stage 6 where the first node of stem elongation is felt above the soil surface. This is the last stage where we suggest that a nitrogen (N) application will produce a substantial yield increase if the plants are deficient in N. Later applications tend to increase the protein content of the finished grain but do not give you the yield increase seen with the early application of N fertilizer.

We have seen increases in yield (5 to 8 percent) for split applications of nitrogen and this increase appeared to be relatively independent of the total rate of N applied. The increase was found when the total application was 60 lb N/acre as well as when the total application was 140 lb N/acre. If you were successful earlier this spring in applying the first split of N to the field and did not reach the maximum rate allowed by your nutrient management plan, an additional application prior to growth stage Feeke’s 6 should provide you with a yield increase. Unless you have not been able to apply any N to the wheat up to this point, avoid traffic on wet fields as the damage done through compaction and rutting of fields can easily add up to the small yield increase seen when N applications are split.

Boost Spring Pasture and Hay Field Productivity

Richard Taylor, Extension Agronomist; rtaylor@udel.edu

Many equine and animal producers are running close to the edge this year with hay supplies since the frequent and heavy rainfall last summer either resulted in lower quality hay or prevented hay making completely. Grazers as well as hay producers should consider fertilization of their fields as soon this spring as soil conditions permit. The heavy rainfall last fall and over the winter months has leached nitrogen (N) and sulfur (S) from the upper rooting zone in pastures and hay fields.

Nitrogen application boosts the growth rate of the grass component in pastures and hay fields and with the very cold start to spring this year and the short hay supplies most producers will want to get their pastures and hay fields off to a rapid start. At least in the northern portion of Delaware, pastures and hay fields are just beginning to green up and start spring growth. With warmer temperatures and drier conditions expected until Tuesday of next week, now is the time to fertilize pasture and hay fields. Many producers will be using urea (46-0-0) as their primary N source but since S has leached out of the upper rooting zone in the soil, I suggest that producers consider applying at least a portion of the required N as ammonium sulfate. Application of both nutrients will ensure that the proper N to S ratio is available so that the sulfur containing amino acids are produced by the plant. Ammonium sulfate is the most acidifying of the N fertilizers but the proper N:S ratio is required by pasture plants.

If the pasture or hay field has a significant amount of legume (white, red, or alsike clover or alfalfa) present, you should limit the N rate to 20 to 30 lbs N/acre and in that case I would use 100 percent as ammonium sulfate. For pure grass hay fields or pastures with less than 25% legumes, apply about 50 lbs of N/acre per ton of expected yield. Apply about half of the N from ammonium sulfate but once the S application rate reaches about 40 lb S/acre change back to pure urea or other N source. You are unlikely to see a response past the 40 lb S/acre/year rate.

Winter Injury in Fruits

Gordon Johnson, Extension Vegetable & Fruit Specialist; gcjohn@udel.edu

We are finally seeing bloom in fruit crops. Plums and apricots are in mid-bloom, peaches and nectarines are just starting to bloom. This is about 2 weeks later than the average.

As bloom occurs, winter damage to buds will become evident. Cold susceptible plants such as blueberries, wine grapes, peaches, blackberries and nectarines can have bud damage when winter temperatures drop below -10°F. There is a lot of variation between grape varieties. Many of the European wine grapes will have damage between zero and -10 F, hybrids and American types can withstand lower temperatures. Other fruits are more cold-hardy. Cherries and European plums can withstand -20 to -25°F and apples and pears go to -25°F without damage. Delaware had temperatures approaching -10°F in some areas. Initial observations indicate that sensitive peach and grape varieties have bud damage.

Fruits that were under stress in 2013 may also show more winter injury. We had significant water damage in lower areas of fields last year and trees, vines, or canes with root damage from waterlogging may also have increased winter injury. Trees with high or excessive fruit loads in 2013 may also show increased winter damage.

High Tunnel Planting Scheduling – Working Out a Schedule for Successive Plantings

Rose Ogutu, Horticulture Specialist, Delaware State University rogutu@desu.edu

High tunnels offer flexibility in crop production and can handle diverse crops from asparagus to zucchinis and many crops in between. High tunnels create an environment, one hardiness zone warmer than the field. The only time not to plant is when daylight does not allow any growth at all, but one can schedule crops in high tunnel to continue all year long. Once day length exceeds 10 hrs per day in late January, seeding of plants in high tunnels can commence, especially with adequate soil temperatures (>55°F). The cropping system should take advantage of season extension while ensuring good use of high tunnel space. The capability of starting your own seeds or having a source of seedlings or planting material whenever needed is important. Growers involved in supplying their CSAs, local restaurants and wholesale markets are always thinking ahead and should develop a good successive planting schedule.

At this time high tunnel producers are done with winter production season and have moved on to spring production. In hind sight, and with this past winter season in mind, early planting and establishment of crops is very important. October 15 should be the latest fall planting date considered for winter harvesting. Having gone through a long, comparatively cold winter, some lessons have been learned. Provision of minimal supplemental heating during extreme cold situations and an inside layer of row covers help a great deal. During the winter months, one needs reliable production of spinach, lettuce, radish, carrots etc. Cultivars of these crops that may be tolerant of freezing temperatures should be considered. Part of the winter’s activities involves pulling out some fall plantings in January or February to open space for re-seeding. The crops to be removed could be lettuce, cilantro, Asian greens, claytonia, corn mache, kale or any other crops in the decline. End of winter and spring management of the high tunnel is often marred with uncertainties of what best to plant and plans for the main planting season.

Succession planting can continue in spring. Crops that could be planted between end of winter and summer include leaf lettuces, spinach, bulbing onions, spring carrots, cilantro, kale, baby chard, and arugula, which may reach maturity in the 12th week window (May 1 to June 1). Tomatoes should be in the high tunnel by May 15. (The last day of frost in Delaware is May 1, but attention has to be paid to the weatherman.)

Summer high tunnel crops considerations. Temperatures in the hot summers soar high. Temperatures can rise well above 90°F and temperatures above 85°F reduce pollen formation in most crops. For the 2012 growing season, high tunnel temperatures at Smyrna Outreach and Research Center (DSU-SORC) averaged 12.0°F warmer than the outside air with the maximum averaging 18.3°F and the minimum averaging 5.2°F. Good ventilation depends on high tunnel design and orientation with regard to adequate air flow. Growers normally wonder about a summer high tunnel crop that will yield in a three-month window with an advantage of being grown inside, rather than in the field. Eggplants (oriental) and hot pepper tolerate the high temperatures. Use of shade cloth (30-50%) lowers air temperatures within the high tunnel by as much as 5 – 8°F. Shade fabric will reduce light intensity and air temperatures and reduce water and nutrient uptake by plants. Evaporative cooling with mist nozzles can be used to keep leafy greens cool.

Fall high tunnel production. A succession planting plan for direct seeded spinach or leaf lettuce in the fall, followed by transplanted heading varieties in the early spring can be used to achieve a nice, diverse crop offering. Carrots and scallions must be planted early in August to size up for winter. For success, crops should be seeded by October 1 or transplanted by October 15. Note that there are some fall plantings that can be left until the summer crop is planted. These are crops like spinach, parsley, dill, chamomile, chard, scallions, beet root, kale and leafy lettuce (var. Tango).

Table 1. High Tunnel Cultivar and Scheduling Examples from the Delaware State University (DSU), Smyrna Outreach Research Centre (SORC).

Cultivar suggestions are based on experiences from DSU-SORC and other high tunnel locations within Delaware. The cultivars are not a result of extensive comparison trials, other varieties can be considered with good or better results.

Crop Cultivar Suggestions Direct Seed (DS) or Transplant (TP) Seeding Date* Calendar Week
Asian greens; Tatsoi, chois, komatsuna, Chinese cabbage Various TP: Jan 14 3
Baby Salad mix and baby leaf crops; red and green oakleaf lettuces, mizuna or waido, red mustard, red Russian kale, spinach, bull’s blood beets, arugula etc. Various fast and slow DS: Jan 14 to Feb 1 3-5
Beets Kestrel, Red Ace, Ruby queen, Zeppo DS: Jan 14 to Feb 1 3-5
Broccoli Arcadia, Belstar, DeCicco, Eureka TP: Feb 21 7
Brussels Sprouts Jade Cross E TP: Feb 21 7
Carrots Envy, Moonraker, Sugar Snax, Napoli DS: Feb 1 5
Cabbage Quick Start, Ramada TP: Jan 14 2
Chard Bright Lights TP: Jan 14 2
Cilantro Santo DS: Feb 1 5


Collards Champion, Flash TP: Jan 14 2
Cucumber Cortez, Indy TP: Mar 27 12
Egg plant Epic, Nadia, Orient Express TP: Mar 1 9
Kale Vates, Red Russian, Blue Knight TP: Jan 14 2
Lettuces Aruba, Emosa, Various TP: Jan 14 2
Pepper Ace, Carmen TP: Feb 21 7
Raddichio Indigo TP: Jan 14 2
Radish Easter Egg, D’avignon, Cheriette DS: Feb 21 7
Scallions Evergreen Hardy White DS: Feb 1 5
Spinach Space, Tyee, Renegade TP: Jan 14 2
Summer Squash Zephyr TP: Mar 13 10
Tomato Various, Better Boy, Prudens Purple, Mountain fresh TP: Feb 21 7
Turnips Hakurei, Scarlet Queen DS: Feb 1 5
Zucchini Sultan TP: Mar 13 10


Baby Salad various DS: Aug 27 to Oct 1 34-39
Beet Ace, Golden DS: Aug 8 to Sept 15 31-37
Carrots Sugar Snax, Napoli DS: Aug 6 31
Chois Various TP: Jul 24 to Aug 7 29-31
Cilantro Santo DS: Sept 4 to Sept 20 35-38
Collards Flash TP: Jul 24 to Aug 7 29-31
Kale Red Russian, Winterbor TP: Jul 24 to Aug 7 29-31
Lettuce Aruba, Emosa, Winter Density TP: Aug 13 33
Radish D’avignon, Cheriette DS: Sept 1 to Sept 30 35-39
Scallion Evergreen Hardy White DS/TP: Aug 6 31
Spinach Space, Tyee, Renegade DS/TP: Aug 20 to Oct 15 33-41
Swiss Chard Bright Lights TP: Jul 24 to Aug 7 29-31

*Dates refer to approximate date of seeding, whether you are direct seeding or transplanting at a later date. Consider dates as ranges.

Amstrong and Neely Kynyon. Early Planting of Tomatoes in High Tunnel with Plant Coverings. http://www.ag.iastate.edu/farms/10reports/Armstrong/EarlyPlantingTomatoes.pdf

Craig Chase and Linda Naeve. January 2013. Vegetable Production Budgets for a high tunnel.  http://www.extension.iastate.edu/agdm/crops/html/a1-23.html

Hoophouse cultivar and scheduling. Michigan State University Organic Farm. http://www.hoophouse.msu.edu/assets/custom/files/General%20High%20Tunnel%20Planting%20Schedule.pdf

Lewis W. Jett. June 2013. http://hightunnels.org/high-tunnel-temperature-management/

Taunya Ernst, Dan Drost and Brent. March 2012. High Tunnel Winter Spinach Production. http://extension.usu.edu/files/publications/publication/Horticulture_HighTunnels_2012-02pr.pdf