Volume 12, Issue 20                                                                     August 6, 2004



Vegetable Crop Insects - Joanne Whalen, Extension  IPM Specialist;   jwhalen@udel.edu


Be sure to sample fall planted fields for diamondback and cabbage looper larvae. We can find both insects in recently planted fields. If both species are present, Avaunt, a Bt, Proclaim or  Spintor  will provide control. If cabbage looper is the predominant species, a pyrethroid, Intrepid, or Confirm  will also provide control.

Lima Beans.
Continue to scout for lygus bugs and stinkbugs as soon as pin pods are present. Treatment should be considered if you find 15 adults and/or nymphs per 50 sweeps. You should also start scouting fields with pin pods for corn earworm. A treatment will be needed if you find one corn earworm larvae per 6 ft of row from late flat pod stage until harvest.  Capture, Mustang, Lannate or Warrior will provide corn earworm control.

Continue to scout all melons for aphids, cucumber beetles, and spider mites. Be sure to watch for bees foraging in the area and avoid insecticide applications on blooming crops. 

Be sure to maintain a 5-7 day spray schedule for corn borer control. Since corn earworm populations are starting to increase in many locations, you will also need to consider treating for corn earworm.
 Continue to scout for beet armyworm, especially if fields are weedy.  Avaunt, Intrepid and Spintor will provide the best beet armyworm control.

Snap Beans.
At this time, all fresh market and processing snap beans will need to be sprayed for corn borer from the bud stage through harvest. With the increase in corn earworm trap catches, you will also need to consider this pest when making your chemical selection. Remember, Orthene provides poor corn earworm control. So if Orthene is used at the pin stage, a pyrethroid should be added to the mix. Since moth catches can change quickly, be sure to check our website for the most recent trap catches and information on how to use this information to make a treatment decision in processing snap beans. (http://www.udel.edu/IPM/traps/latestblt.html and http://www.udel.edu/IPM/thresh/snapbeanecbthresh.html). 

 Sweet Corn.
All fresh market silking sweet corn should be sprayed on a 2-3 day schedule.  Since corn earworm populations have increased quickly in some locations, be sure to check trap catches frequently. You can check trap catches and treatment decision guidelines on our website (http://www.udel.edu/IPM/traps/latestblt.html and http://www.udel.edu/IPM/thresh/silkspraythresh.html). Continue to watch for fall armyworm feeding in the whorls. A treatment is needed if you find 12-15% of the plants infested. Generally, 2-3 whorl sprays are needed to achieve control. In whorl stage corn, Avaunt, Lannate, Larvin and the high rate of Warrior have provided the best control in recent years. In addition, we also have a 24C SLN label for Lorsban 4E for armyworm control in sweet corn. With all products, the best control will be achieved if worms are small at treatment time.  Also be sure to check all labels for grazing restrictions and feeding restrictions for corn silage, forage or fodder.  In addition, if fall armyworm pressure is heavy in your whorl stage fields (above 30% infested plants), you should consider a combination of a pyrethroid plus Lannate, Larvin or Lorsban for the first 1-2 silk sprays.  Be sure to check labels for days between last application and harvest for all materials.

Lima Bean Fields Are Being Sprayed for Downy Mildew Prevention Ed Kee, Extension Vegetable Crops Specialist; kee@udel.edu


With conditions favorable for the development of Downy mildew (Phytophthora phaseoli)  on lima beans, many processors, consultants, and growers are taking steps to prevent Downy mildew on lima beans.  While no outbreaks have been reported in commercial fields, we have seen some Downy mildew on home garden pole lima beans.  Typically, preventative applications of a fixed copper (Champ DP or Kocide 2000) are being applied, often in conjunction with insect sprays, but not necessarily. 


If Downy mildew is suspected or found on lima beans, please contact your county agent, an Extension plant pathologist, or me.  We are interested in determining what races of Downy are present.


This Downy mildew is a different species of fungus from the Downy mildew fungus that attacks cucurbits (Pseudopersonospora cubensis).


Please refer to Issue 19 for specific spray recommendations.




Downy Mildew on Pickling Cucumbers Ed Kee, Extension Vegetable Crops Specialist; kee@udel.edu


This Downy mildew (Pseudopersonospora cubensis) is still plaguing all cucurbit crops, including watermelons, cantaloupes, pumpkins, squash, and cucumbers.  Yields of pickling cucumbers are reduced from the inability of the plant’s foliage to support fruit growth and from the interruption of pollination due to the adverse impact on the pollinator varieties.  The latter situation is especially true with varieties that use older, less resistant pollinators, and results in a high percentage of unusable fruit.


Early reports from North Carolina on the Downy mildew infection on the fall crop are discouraging.   Even with a rigorous fungicide program, many fields are showing Downy mildew infection.


If there is any good news in all of this, it is that this organism does not over winter in our region.  The source of primary innoculum for our region is considered to be wind-borne sporangia from infected cucurbits grown in areas to the south of us.  Historically, the conventional wisdom has identified Florida as the primary source, with the sporangia moving up the coast as the season progresses.  Typically, we don’t see Downy mildew on cucurbits until mid-August or September.


As a reminder, this fungus infects only members of the Cucurbitacae family. 




Spinach Planting Will Begin Soon Ed Kee, Extension Vegetable Crops Specialist; kee@udel.edu


Spinach plantings for fall harvest will begin soon.  Successful weed control programs in the past have utilized Ro-Neet used as a pre-plant incorporated material, and Dual as a pre-emergence material.  Ro-Neet can be applied at 3-4 pints/acre and incorporated into the soil at 2-4 inches.  This should be done 7 to 10 days in advance of planting to reduce potential injury.  Ro-Neet will do a good job of controlling most grasses and the broadleaf weeds pigweed and purslane.  It will do a fair job on common lambsquarter.


Dual Magnum has a 24c special local needs label for pre-emergence control of weeds in spinach.  This label is in place for Delaware, Maryland, Virginia, and New Jersey.  Dual will provide control of the same weeds, but also have good activity on yellow nutsedge, hairy galinsoga,  and eastern nightshade.  The labeled rate is 0.33 to 0.67 pints per acre.  Sandy, or coarse textured soils should receive the lower rate.


If Ro-Neet and Dual are going to be used, consideration should be given to reducing the Ro-Neet rate to the 2-3 pint range, again to help avoid potential injury.


Post-emergence herbicides such as Poast 1.5 EC and Select 2EC are available for grass control later in the season if necessary.  Spin-aid is available for post-emergence control of chickweed and other broadleaf weeds in the fall months only.




Vegetable Crop Diseases - Bob Mulrooney, Extension Plant Pathologist, bobmul@udel.edu


Late Blight Advisory.


Disease Severity Value (DSV) Accumulation as of August 4, 2004 is as follows:

Location: Joe Jackewicz Farm, Magnolia, DE. Greenrow: April 25, 2004




Daily DSV


Total DSV

Spray Recommendation


































































Application rates for protectant fungicides (Dithane, Bravo, etc.) should be at the high end of the rate with the amount of foliage present. For specific fungicide recommendations, see pages F132-33, 2004 Delaware Commercial Vegetable Production Recommendations Book. EB 137.


No late blight has been seen in DE-MD area on potatoes.


Note:  Late blight has been confirmed on tomato in Burlington County, NJ and is present in southeast PA on tomato as well. Conditions have been very favorable for it to appear if the fungus is present. Growers with late potatoes and those that may have tomatoes nearby should continue to spray and scout for symptoms.


                                                                                    Photo by Bob Mulrooney


Late blight on tomato leaf.


Note the white ring of the late blight fungus sporulating on the edge of the lesion.






Field Crops


Field Crop Insects - Joanne Whalen, Extension  IPM Specialist; jwhalen@udel.edu


We continue to find low levels of soybeans aphids in all three counties.  You will need to look at the entire plant when sampling for aphids. The treatment threshold is 250 per plant up to growth stage R-3/R-4 with 80% of the plants at that level. After R4, the  threshold increases to 1,000-1,500 aphids per plant. Numerous products are now labeled for soybean aphid including Asana, Baythroid (suppression only), Mustang MAX, Warrior, and Lorsban. Dimethoate has not provided adequate control and Furadan 4F only has a 2ee label for the Midwestern states.


We are starting to find a few corn earworms in double cropped fields; however, populations are extremely low at this time. With the increase in moth catches in North Carolina and the eastern shore of VA as well as a significant increase in our own pheromone traps as well as some BLT locations, you will need to start sampling soybean fields for earworms by mid-August. Although full season fields should generally escape damage, it will be important to check those fields at least 2 times to be sure that you do not miss an infestation. As in most years, double crop fields will be most susceptible to attack. A treatment should be considered if you find  3 per 25 sweeps in narrow fields and 5 per 25 sweeps in wide row fields (20-inches are greater).


The following materials will provide corn earworm control in soybeans: Ambush, Baythroid, Asana, Mustang MAX, Pounce, Warrior (all pyrethroids), Larvin, Lorsban or Steward.  Larvin and Steward act by ingestion on both small and large larvae. Remember that if you are using a pyrethroid, the primary mode of action on large larvae will be ingestion. Earworms will need to feed to cause death so you will not see much activity from the contact action. Once they ingest the product, they immediately stop feeding. Therefore, fields should not be evaluated for control until 4 days after application. Small larvae are generally killed by contact as well as ingestion.  It is important that you do not look at fields 1-2 days after spraying and assume control failure if large worms are present. This could result in unnecessary re-sprays. We are also finding a few beet armyworms in fields. If the predominant pest is beet armyworm, the pyrethroids will not provide control. Steward would be the preferred material. However, in 2002 grower demonstration trials, Lorsban also provided good control.




Field Crop Diseases - Bob Mulrooney,

Extension Plant Pathologist, bobmul@udel.edu



Leaf blights and spots are on the increase. Northern corn leaf spot often called Carbonum leafspot race 3 produces small spots that look like beads on a string. They eventually produce long (several inches) narrow lesions with reddish brown borders. These spots are small.


Photo by Bob Mulrooney

Closeup of Northern corn leaf spot or Carbonum race 3


Northern corn leaf blight was also seen recently. These spots are cigar-shaped and can be very large and wide compared to either Carbonum race 3 or Southern corn leaf blight.


                                                                                       Photo by Bob Mulrooney

Northern corn leaf blight. Note the large spots. The smaller spots near the mid-rib are Carbonum race 3 spots for comparison.




Grain Marketing Highlights - Carl German, Extension Crops Marketing Specialist; clgerman@udel.edu


Selected Grain Marketing Highlights

Executive Summary
The commodity markets are reacting to a round of positive fundamental and technical factors in today's trading (8/05/04). The first being combined export sales (both old crop and new crop) were reported to be higher than expected for
U.S. corn and soybeans, and mid-range for wheat.

Corn Analysis.
Combined export sales for corn, reported at 43.9 million bushels were well above the high end of pre-report estimates of 35.4 million bushels. An additional sale of 120,000 metric tons to unknown sources was also reported this morning. Corn carry over, projected for the end of the current marketing year, is at a low level. The corn market is currently oversold. Demand is currently picking up, due primarily to the near $1.00 per bushel decline in the value of December corn futures since the first of June. No one is currently priced out of the corn market, at current price levels!!! We are likely to use whatever crop size the USDA settles on in the next production estimate which is due out on Thursday, August 12th. Translated into English that means "whatever the corn crop size is, we will probably use it". An initial estimate from one private forecaster placed U.S. corn production at 10.863 billion bushels.

Soybean Analysis.
Combined export sales for U.S. soybeans were reported at 12.8 million bushels, above trade expectations. The soybean market needs to maintain evidence of strong demand in the weeks ahead due to the fact that we do not see any significant weather problems at the present time. The soybean market is also currently oversold. In today's trading, soybean oil prices were driving some short covering (funds offsetting, creating a buy, that creates a short term rally). The soybean pipeline (carry over situation) is at or near a record low. Similar to corn, no one is priced out of the soybean market at current price levels, with soybean prices declining nearly $2.00 per bushel since the first of June. One initial private estimate of the U.S. soybean crop size was placed at 2.944 billion bushels.

Wheat Analysis.
Export totals were placed at 18.5 million bushels, mid-range to pre-report trade expectations. The wheat harvest is over. Look for a post harvest bounce in wheat prices, supported by the fact that is what usually happens and wheat futures are also currently oversold. Wheat futures are also likely to trade in concert with corn and soybean prices.

Market Strategy.
Now is not the time to be a seller of corn, soybeans, or wheat. Demand is picking up. The next crop report is due out next Thursday. We have to see crop production levels of around 11 billion bushels for U.S. corn and 3 billion bushels for U.S. soybeans for the report to be called bearish. Remember, although this may not be the time for grain sellers to be advancing new crop sales, it is the time for grain users to be booking input needs.


2004 Small Grain Variety Trial Results Online

The 2004 Small Grain Variety Trial Results for New Castle, Kent and Sussex Counties are available at the following address:







AUGUST 23-24, 2004








August 23, 2004


Linvilla Orchards*, Media PA

Funks Farm Market & Garden Center, Millersville, PA

Brown’s  Orchard & Farm Market, Loganville, PA

Maple Lawn Farms,  New Park, PA

Hickory Bridge Farms, Orrtanna, PA.

Hotel Liberty


August 24, 2004

Lady Moon Farms/Trickling Springs Creamery* Chambersburg PA

Willow Pond Farm, Fairfield, PA

Adams County Winery, Orrtanna, PA

Quaker Valley Orchards, Biglerville, PA


We are inviting all of you to join us.  Transportation, lodging, meals taxes and gratuities are included.  The cost is $ 80.00 per person double occupancy. 


We will leave Dover at 7 AM on MONDAY 8/23  return TUESDAY night at 9:30 PM


PHONE 302 730-4000 by August 19th if you will be going on this tour, or email Gordon Johnson (gcjohn@udel.edu). For more information contact our office at 302 730-4000.  


Tour sponsored by the University of Delaware Cooperative Extension, The Delaware Department of Agriculture, and  The Northeast Center for Risk Management Education.  












Agronomic and Vegetable Field Tours

Wagons will depart from the area located behind the pesticide storage and handling facility from 8:30 a.m. – noon


¨ Irrigation and Nitrogen Management for Seedless Watermelons

Seedless watermelons have become an important crop in Delaware. A drip irrigated study is underway to develop guidelines for the optimal amount of water and nitrogen to apply. Four replications of low, medium and high water applications, and low, medium and high nitrogen rates are being used. Data from the nearby UD weather station are being used to estimate crop water use to determine the three irrigation amounts. At the same time, soil moisture content is being measured with a number of instruments to compare them and to determine their effectiveness in managing irrigation. One of the instruments automatically measures soil moisture down to 2 ft every 10 minutes, while the other instruments are not automatic and are used as required. Cooperating in this project are the USDA ARS and T-Systems International, a commercial manufacturer of drip irrigation equipment.  Ian McCann, Assistant Professor, Extension Irrigation Specialist; James Adkins, Extension Associate, BioResources Engineering; Tracy Wootten, Horticulture Agent; Ed Kee, Extension Vegetable Specialist



¨Understanding Surfactants and Their Role in POST Herbicide Programs

Herbicides are commonly used to control weeds after they have emerged (postemergence).  Most of these herbicides require an adjuvant to optimize their performance.  This stop will discuss the various types of adjuvants and highlight University of Delaware research with adjuvants for a wide range of herbicides.  Mark VanGessel, Associate Professor/Extension Specialist, Weed and Crop Management; Quintin Johnson, Extension Associate, Weed Science; Barbara Scott, Research Associate, Weed Science


¨Corn Breeding and Commercial Corn Hybrid Trials

The 2004 Commercial Hybrid Trials will be featured.  Corn breeding activities at the Research and Education Center include breeding for improved agronomic performance, nitrogen utilization, and disease/pest resistance.  An overview of the University of Delaware’s collaborative research with the USDA GEM (Germplasm Enhancement of Maize) Program will also be presented.  Jim Hawk, Tecle Weldekidan,  Bob Uniatowski,, Travis Frey, Professor, Associate Scientist, Associate Scientist, Graduate Student, respectively; Department of Plant and Soil Sciences; Kelvin Grant, Ph.D. Candidate, Cornell University


¨Roundup Ready and Traditional Soybean Blends – Reducing Production Costs

With the seed cost of Roundup Ready soybean varieties rising year after year, some growers have expressed interest in ways that seed costs can be minimized while still planting enough seed to quickly obtain canopy closure for more effective weed control and moisture conservation.  From a proposal that was funded in 2004 by the Delaware Soybean Board, we have established soybean blend studies in four locations on Delmarva.  The studies are designed to evaluate various blends of Roundup Ready soybeans with a non-Roundup Ready variety of the same maturity group.  Blends are based on an initial soybean population of about 150,000 or 200,000 (an optimum and high target population) pure live seed per acre with replacement of up to 50 percent of the seed with the non-Roundup Ready variety.  The study will look at factors such as light penetration through the canopy, lodging, yield, and production cost per bushel of yield to determine the effectiveness of blends for producing yield and controlling costs.  Richard Taylor, Extension Agronomist, University of Delaware; Robert Kratochvil, Extension Agronomist, University of Maryland; Maria Labreveux, Agronomist, Delaware State University; Bob Uniatowski, Associate Scientist, University of Delaware  


Chestnuts – Alternative Tree Crop for Delaware

Hearing the refrain of “chestnuts roasting on an open fire” bring nostalgic memories for many of our parents and grandparents.  For others, the fall chestnut season brings memories of old world traditions.  Well before the first settlers arrived on our shores, the American chestnut tree stood as a mighty monument.  The American tree was a giant of the forest towering to 100 feet tall.  From Maine to Florida and spreading west of Michigan, the American Chestnuts were the predominant trees of the eastern forests.


Since 1995, the University of Delaware has been in the forefront of restoring chestnut as a commercially viable crop in the United States.  Learn first hand the efforts to establish a commercial industry and see the trees that are making this venture possible.  Additional information on chestnuts will also be available.  Gordon Johnson, Extension Agent


♦ Agritourism and Entertainment Farming Opportunities in Delaware

There are many opportunities to bring extra income to the farm by creating tourist or entertainment related attractions.  Delaware Cooperative Extension in cooperation with the Delaware Department of Agriculture and the newly created Delaware Agritourism Association is offering educational opportunities for farm families interested in learning more about agritourism or entertainment farming.  At this stop, we will discuss current educational programs in these areas and then cap it off with the opportunity for tour participants to go through one of three mini mazes, a popular attraction that several Delaware farms are offering.  Gordon Johnson


Sick Plant Clinic

Bring your landscape and garden problems in for diagnosis from 8:30 a.m. – noon

(located at the Master Gardener area)


Weed Identification Area

Challenge your skills in identifying common troublesome weeds found in field and vegetable crops, gardens, and lawns from 8:30 a.m. - noon

(located near the Master Gardener area)


Sussex Master Gardener Demonstrations

Exhibits and seminars open from 8:30 a.m. –

1:30 p.m


The garden has been expanded again this year and is filled with new plants and new ideas to make your garden and landscape attractive and easy to maintain.  The garden continues to evolve and mature, and features the following demonstrations: 

Herbs, Shade-loving plants, Annual flowers, Perennial border garden, Bog garden, Containers, Azalea trial, Hydrangea trial, Sunflower variety demonstration, Tomato variety demonstration, Clematis trial


4-H Farm Animal Display

Located west of the grove area (near the Lasher Lab) from 9:00 a.m. - 1:00 p.m.


This exhibit will highlight animal care, history, and production related to the following animals:  calves, pigs, sheep, goats, ponies, chicks, rabbits, and ducks.  Animal owners and 4-Hers will be on hand to answer your questions.  Animals will be available for petting.  Mary Argo, Extension Educator, 4-H


Sussex County Safe Kids Day Activities

Located in the tent west of the grove from  9:00 a.m. – 12:00 noon



The theme for the 2004 Sussex County Safe Kids Day is “Summer Splash.”  This year’s

      emphasis identifies risks associated with popular summer activities and the unfortunate escalating number of recreational and sport-related activities.  Parents and children think of summer as the season for fun and relaxation, but emergency room doctors know it as “trauma season.”  In fact, children will be rushed to emergency rooms nearly 3 million times this summer.  To help kids learn to play safe, this year’s program will focus on bicycles, scooters, motor vehicles, all-terrain vehicles, water safety, and many other fun activities that can cause injuries.  Since education should be fun, an obstacle and skills course will be used to teach many of the critical safety lessons.  Participants will learn about childhood injury prevention from dynamic speakers, exhibits, costumed characters and interactive exhibits.  This festival of education and entertainment will include the following:


Safety obstacle course, Safety expo, Safety demos, Refreshments, Safety kits for first 750 children, GM car seat check, Patriotic opening, Little train rides, Face painting, Finger painting, Costumed characters, Hoop shoot, Petting zoo,

4-H entertainment, Safety queens, Children’s garden tour, Cat Country Radio – Broadcasting live, And much more


Mike Love, Extension Agent, Highway Safety; Ron Jester, Extension Safety Specialist


Luncheon Program

12:00 Noon in the grove

A catered luncheon will be followed by a brief program.  Tickets will be available for $6.00 person at the information table.  (Tickets are limited so early purchase is recommended.)


Other Events and Activities


Many agricultural-related demonstrations and exhibits will be on display beginning at 8:30 a.m.  The legendary sounds of  “Bunky and Dottie” Eye will entertain visitors in the grove area from 10:00 a.m. – 12:00 noon featuring Rock “N” Roll, New Country, Old Country, Pop and Gospel songs – entertainment for all ages. 


For more information contact:  Mark Isaacs or Barbara Stephens, University of Delaware, Research and Education Center, 16483 County Seat Highway, Georgetown, Delaware 19947, (302) 856-1997.




                     Weather Summary


Week of July 30 to August 5, 2004


0.02 inches: July 30

0.02 inches: July 31

0.02 inches: August 1

1.22 inches: August 2

0.32 inches: August 3

0.26 inches: August 4

0.14 inches: August 5

Readings taken for the previous 24 hours at 8 a.m.


Air Temperature:

Highs Ranged from 89°F on August 4 to 76°F on August 5.

Lows Ranged from 73°F on July 31 to 67°F on August 4 & 5.


Soil Temperature:

79°F average.

(Soil temperature taken at a 2 inch depth, under sod)


Web Address for the U of D Research & Education Center:  http://www.rec.udel.edu



Compiled and Edited By:

Tracy Wootten

Sussex County Extension Agent – Horticulture

University of Delaware





Cooperative Extension Education in Agriculture and Home Economics, University of Delaware, Delaware State University and the United States Department of Agriculture cooperating.  Distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914. Delaware Cooperative Extension, University of Delaware. It is the policy of the Delaware Cooperative Extension System that no person shall be subjected to discrimination on the grounds of race, color, sex, disability, age or national origin.


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