Volume 7, Issue 20                                                                                             August 13, 1999

Vegetables

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

Cabbage.

Be sure to scout recently transplanted fields for economic levels of diamondback and cabbage looper. Spintor or a Bt insecticide will control both insects. Confirm is now labeled on cabbage and will provide good cabbage looper control. A treatment should be applied if 5% of the plants are infested with larvae. Spintor will provide excellent control of diamondback larvae at the 3-ounce rate. The higher rate, 4-6 oz per acre, is needed if cabbage loopers are also present.

Lima Beans.

Continue to sample fields with pin pods for earworm, lygus and stinkbugs. A treatment should be applied if you find one corn earworm per 6 foot of row or 15 tarnished plant bugs and/or stinkbugs per 50 sweeps. Lannate or Capture can now be used to control all 3 insects on lima beans.

Peppers.

Maintain a 7-10 day schedule for insect control. Since control is now needed for corn borer, corn earworm and aphids, Lannate should be used to provide control of all 3 insect pests.

Snap Beans.

Processing snap beans should be sprayed at the bud and pin stages with Orthene for corn borer control. Capture applied at these stages has also provided corn borer and corn earworm control in research trials. If Orthene is used at the pin spray, Asana or Capture will also be needed for corn earworm control. At this time, 2 applications of Lannate or Capture on a 5 –6 day schedule will be needed between the pin spray and harvest.

 

Spinach.

In recent years, seed corn maggot have caused economic losses in fall planted spinach, especially when residue from a previous crop is plowed under close to planting the spinach crop. A broadcast application of Diazinon applied immediately before planting and incorporated into the top 3-4 inches of soil has provided control.

Sweet Corn.

Fresh market silking sweet corn should be sprayed on a 3-day schedule throughout the state. Be sure to check the Crop Pest Hotline (in state: 1-800-345-7544; out of state: 1-302-831-8851; www.udel.edu/IPM) for the most recent nightly trap catches in your area.

Vegetable Diseases - Kate Everts, Extension Vegetable Pathologist, University of Delaware and University of Maryland; everts@udel.edu and Phil Shields University of Maryland; ps136@umail.umd.edu

 

MELCAST for Fungicide Application on Watermelons.

Do not use MELCAST if there is a disease outbreak in your field, it is a preventative program. Below are the EFI values from weather stations located on the Eastern Shore August 4– August 11. Any questions please call Phil Shields at (410) 742-8788 or e-mail: ps136@umail.umd.edu

EFI Values for 1999

Location

8/4

8/5

8/6

8/7

8/8

8/9

8/10

8/11

U of M, LESREC
Salisbury,MD

3

3

4

3

2

1

1

2

Wootten Farms, Galestown,MD

1

1

3

1

1

2

0

0

Mark Collins,
Laurel, DE

3

3

4

3

2

1

1

2

Vincent Farms Laurel, DE

2

2

4

2

1

1

1

2

D C Farms,
Bridgeville, DE

2

2

3

2

2

3

1

0

Balvin Brinsfield,
Vienna, MD

2

3

2

2

1

1

0

1

Charles Wright,
Mardela Springs, MD

3

2

5

4

1

1

1

2

U of D, REC Georgetown, DE

1

2

2

2

2

3

0

0

Watermelon Fields should be sprayed with a fungicide when 30 EFI values have been accumulated by the weather station nearest your fields. Add 2 points for every overhead irrigation. After a fungicide spray, reset your counter to 0 and start over. If a spray has NOT been applied in 14 days, apply a fungicide and reset the counter to zero. The first and last day above can be partial days so use the larger EFI value of this report and other reports for any specific day.

 Laurel Farmer's Auction Market Report

August 5, 1999 – August 11, 1999

Quantity

Produce

Price

30,571

Cantaloupes

 

 

Athena

0.25-1.20

 

Super Star

0.25-0.50

 

Passport

0.25-0.40

 

Cordell

0.35-0.45

7,093

Sugar Babies

0.25-1.40

155

Crenshaws

0.55-1.00

2,383

Honeydews

0.30-1.45

 

Yellow Dolls

0.30

436,019

Watermelons

 

 

Crimson Sweet

 

 

12 up

0.40-0.50

 

15 up

0.50-0.95

 

20 up

0.60-2.00

 

25 up

1.00-1.90

 

30 up

2.05-2.50

 

Sangria

 

 

15 up

0.50-2.55

 

20 up

0.75-2.00

 

25 up

1.00-1.55

 

30 up

1.25

 

Yellow Meat

 

 

 

1.20

 

Royal Star

 

 

15 up

0.50-0.55

 

20 up

0.75-0.95

 

All Sweet

 

 

15 up

0.75

 

20 up

0.75-2.85

 

25 up

0.85-2.55

 

Summer Flavor

 

 

15 up

0.95

 

Royal Majesty

 

 

15 up

0.60-0.75

 

Ariba

 

 

15 up

1.00-1.10

 

20 up

1.75

 

Mardi Gras

 

 

12 up

1.00

 

15 up

0.75

 

20 up

1.25-1.35

 

25 up

1.35

 

Seedless

0.35-2.25

99

Peppers

 

 

Green

3.00-7.00

 

Banana

3.00

32

Eggplant

3.50-5.50

1132

Tomatoes

 

 

Red

3.00-7.50

 

Pink

3.00-7.50

54

Sweet Corn Doz.

0.90-1.00

74

Cucumbers

3.00-10.00

185

Squash

 

 

Yellow

3.00-11.50

 

Green

4.00-10.00

12

Potatoes

 

 

Red

4.00-8.50

 

White

 

3

Lima Beans

25.00

3

Okra

4.00

1

Peaches

6.00

Field Crops

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

Soybeans.

In addition to mites, all soybeans should be scouted for podworm activity. Moths can be found laying eggs in fields that are in the bloom to early pod-set stages. No controls will be needed until you find 3 earworms per 25 sweeps in narrow row beans or 5 per 25 sweeps in wide row beans. A pyrethroid or Larvin will provide the most cost-effective control.

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

USDA Releases August Crop Report
Recent rains in parts of the mid-west and a slightly bearish crop report are going to make for interesting developments in the commodities markets this week. The pending question will be whether USDA has adequately estimated the size of the 1999 U.S. corn and soybean harvest.


With only a slight reduction in USDA's estimate for U.S. soybean production, now placed at 2.838 billion bushels, traders viewed the report as negative to soybean prices. Nevertheless, ending stock
estimates for U.S. soybeans were reduced 50 million bushels, from 590 to 540 million bushels. It is important to note that the negative reaction to the August 12th crop report is expected to be short lived.

Sentiments of traders were running the same for U.S. corn based upon a higher than expected production estimate, now placed at 9.561 billion bushels. Ending stocks for corn were only reduced by 11 million bushels. Both corn and soybean production estimates were well above the high end
of pre-report estimates for 1999 production. Grain merchants in the mid-west were reported as not believing the corn production estimate, expecting that it will move lower over time.

On a positive note, the report for U.S. wheat was viewed as slightly bullish. Forecasted ending stocks for wheat were reduced 29 million bushels.

 Stalk Nitrate Test for Irrigated Corn - Gordon Johnson, Extension Educator –Agriculture; gcjohn@udel.edu

Irrigated corn producers interested in evaluating the efficiency of their nitrogen fertilization program are encouraged to consider doing a stalk nitrate test at the end of this growing season. Corn plants that have more nitrogen than needed to attain maximum yields, accumulate nitrate in their lower stalks at the end of the season. Nitrate levels in irrigated corn that are in the excess range (by the stalk nitrate test) indicates that nitrogen, from fertilizers or manure, was applied at rates that exceed those for economic returns. Excess nitrogen in the soil is also a potential environmental concern, especially in fields that will be fallowed, due to potential winter leaching.

The time for taking samples for stalk nitrate testing is between one and three weeks after black layers have formed on about 80 percent of the kernels of most ears. An 8 inch long sample is cut from stalk bases leaving a 6 inch stub (cut the portion from 6-14 inches above the ground). Leaf sheaths should be removed from the segments. Do not sample severely damaged stalks (diseased, lodged, or insect damaged). Fifteen of these 8 inch stalk samples should be collected randomly from the field or field portion being tested. Areas differing in soil type or management practices should be sampled separately.

Samples should be placed in paper bags (not plastic) and sent as soon as possible after sampling for testing. If samples must be kept for more than a day, they should be refrigerated.

The University of Delaware Cooperative Extension, with grant money from the USDA NRCS is offering a pilot project this summer/fall to collect and send off stalks for nitrate testing in 1999 (irrigated corn only) at no cost to growers. Contact Gordon Johnson at the Kent County Extension Office in Dover, (302) 697-4000, or Derby Walker at the UD Research and Education Center, Georgetown, (302) 856-7303 for additional details.

 

High Nitrates in Forages - Gordon Johnson, Extension Educator –Agriculture; gcjohn@udel.edu

Corn is currently being harvested for silage at this time. Some acreage that would normally have gone for grain is also being harvested for silage because of low potential grain yields.

Drought stressed crops that have received nitrogen fertilizer at rates for a normal crop may have excessive nitrate levels when harvested for forage. High nitrate levels in forages can lead to nitrate poisoning of dairy cattle and livestock. Corn harvested for silage, sudangrass, sorghum, pearl millet, oats, orchardgrass, and tall fescue can all accumulate nitrates at high levels when under stress. Most weeds commonly found in corn also accumulate toxic levels of nitrate, including pigweed, lambsquarters, ragweed, velvetleaf, and black nightshade.

Highest levels of nitrate accumulate when drought occurs during a period of heavy nitrate uptake by the plant. Drought during or immediately after pollination in corn may lead to excess nitrates in the plant. Resumption of normal plant growth after a heavy rainfall will reduce nitrate levels in corn plants, however harvest should be delayed 4 days after the rainfall.

If drought stressed crops are to be harvested for forage, they should be tested before feeding. If feed is to be fed green or as hay, or if very high nitrate levels are suspected, hand harvest from several areas in the field and run through a garden chipper or forage harvester or alternately, machine harvest a representative portion of the field. Remember that those plants under the most stress will have the highest nitrates so you may want to harvest heavily stressed areas of the field separately. Have the samples tested for nitrates as soon as possible.

Ensiling forages can reduce nitrate levels by up to 50%. Silage should be tested after the ensiling process has been completed (4 weeks). Adding 20 pounds of limestone per ton of silage going into the silo will reduce nitrate levels even more (do not add more or fermentation could be affected).

Greatest concentrations of nitrates in corn are in the lower 1/3 of the stalk. If corn has excessive nitrates, consider harvesting higher (leave more of the lower stalk in the field).

Feeding high nitrate forages should be done with caution. For advice on how to feed forages that are high in nitrates, contact Gordon Johnson at the Kent County Extension office (302) 697-4000 or your local extension office.

The Delaware Department of Agriculture and the Maryland Department of Agriculture will run forage samples for nitrate levels for producers in those states. For assistance in sampling forages for nitrate testing or for additional information contact your local extension office.

 Prussic Acid Poisoning Risk Increases Following Droughts – Richard Taylor, Extension Agronomist; rtaylor@udel.edu

Drought-stressed sorghum, like corn, often can be partially salvaged by harvesting it as silage or turning animals on it to graze. This allows the grower to recover some of the value. In other situations, growers may be growing sudangrass or sorghum-sudangrass hybrids for forage or may have johnsongrass or shattercane growing in their corn silage fields. Except for corn, these plants can produce cyanogenic glycosides. Plants accumulate these compounds if rapid plant regrowth occurs after a period of retarded growth such as happens after drought conditions are alleviated by rains. These conditions also occur after light frosts in the fall.

When animals ingest forages with cyanogenic glycosides, prussic acid (cyanide) is freed and is absorbed into tissues where it interferes with the transfer of oxygen in the blood and its use in the tissues. Symptoms of cyanide poisoning occur within minutes of ingestion of suspect forage and include labored breathing, nervousness, irregular pulse, frothing at the mouth, staggering, and convulsions. Unlike in nitrate poisoning where the blood is dark brown, in cyanide poisoning, the blood is bright red. Again, ruminants easily can consume lethal amounts.

What can you do to prevent prussic acid poisoning? Check out the following guidelines.

Do not allow access to wild cherry leaves whether wilted or not. After storms, always check pastures for fallen limbs. Remove them immediately to prevent problems as wild cherry has a high prussic acid potential.

Upcoming Meetings…

Commercial Forage Production Field Day

Establishing and Maintaining Alfalfa and other Forage Crops

Date: Tuesday, August 24, 1999

Place: Thomas Farms, 896 Sandy Bend Road, Marydel, DE

Time: 9:30 A.M. to 11:30 A.M.

Please register in advance by calling Kent County, DE Cooperative Extension Office at (303) 697-4000 by August 23, 1999. Anyone that is interested is welcome to attend. For additional information or special assistance in accessing this meeting contact Gordon Johnson at (302) 697-4000.

(See Issue 19 for more details).

            Weather Summary 

Week of August 5 to August 12

Rainfall:

None

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

Air Temperature:

Highs Ranged from 94°F on August 8 to 81° F on August 9.

Lows Ranged from 74°F on August 8 to 53°F on August 10.

Soil Temperature:

87 °F average for the week.

(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

Extension Associate - Vegetable Crops

 Cooperative Extension Education in Agriculture and home Economics, University of Delaware, Delaware State College and the United States Department of Agriculture cooperating, John C. Nye, Dean and Director. Distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914. Is the policy of the Delaware Cooperative Extension System that no person shall be subjected to discrimination on the grounds of race, sex, disability, age or national origin.

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