Volume 6, Issue 19 July 31, 1998

 

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

Pickling Cucumbers.

The first pickleworm larvae has been found feeding in plant terminals. Young larvae are most easily detected in plant terminals, especially in weedy areas or along field edges. Timing a spray should be based on when larvae are first detected, the population level, and the temperature. All pickleworm stages experience mortality at temperatures above 85 degrees. Young larvae will begin movement to the fruit when they are half grown. In general, no controls are needed unless 5 percent or more of the terminals are infested with small larvae or you find larvae moving out of the terminals and the field is more than 7 days from harvest. Our experience in 1997 indicated that small pickleworms found in the terminals within 5-7 days from harvest did not make it to the fruit. Lannate or Thiodan have provided control. v

Vegetable Diseases - Kate Everts, Extension Plant Pathologist, University of Maryland and University of Delaware ; everts@udel.edu

Spinach.

Damping off in spinach caused by Pythium can result in pre and postemergence seedling death and reduced plant stands especially in fall plantings. To reduce damage from damping off, rotate two years between spinach plantings and apply Ridomil Gold 4E at 1-2 pints/A preplant incorporated, or as a soil surface spray after planting. In addition to reducing damping off damage, Ridomil Gold at planting will provide early season control of white rust. v

Vegetable Diseases - Kate Everts, Extension Plant Pathologist, University of Maryland and University of Delaware ; everts@udel.edu, 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 July 22-29. Any questions please call Phil Shields at (410) 742-8788 or e-mail: ps136@umail.umd.edu

EFI Values

Location

7/22/98

7/23/98

7/24/98

7/25/98

7/26/98

7/27/98

7/28/98

7/29/98

U of M, LESREC
Salisbury,MD

1

1

2

2

0

3

2

5

Wootten Farms, Galestown,MD

1

1

0

0

2

2

0

3

Mark Collins, Laurel, DE

2

2

0

0

3

2

1

4

U of D, REC Georgetown, DE

2

1

1

0

4

2

1

 

Vincent Farms Laurel, DE

1

0

0

0

2

2

1

3

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. v

Laurel Farmer's Auction Market Report

July 23 - 29, 1998

Quantity

Produce

Price

61,776

Cantaloupes

 
 

Athena

0.25-1.70

 

Super Star

0.25-0.95

 

Eclipse

0.30-0.60

 

Passport

0.75-1.10

 

Cordell

0.35-0.35

 

Savor

0.25-0.35

2637

Honeydews

0.60-1.75

203

Crenshaws

1.20-1.35

12915

Sugar Babies

0.35-2.30

 

Yellow Dolls

0.60-1.00

 

Watermelons

 
 

Crimson Sweet

 
 

12 up

0.85-1.30

 

15 up

1.05-2.85

 

20 up

1.35-3.30

 

25 up

2.50-3.75

 

30 up

3.30-3.85

 

Sangria

 
 

12 up

0.95-1.50

 

15 up

1.00-2.25

 

20 up

1.50-3.25

 

25 up

2.00-3.75

 

Royal Sweet

 
 

15 up

0.80-3.20

 

20 up

1.40-2.80

 

25 up

2.60

 

Royal Star

 
 

12 up

2.00

 

15 up

1.70-2.00

 

25 up

2.70-3.35

 

Jubilee

 
 

15 up

2.00

 

25 up

2.60

 

Seedless

1.00-3.95

 

 

 

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

 

Soybeans.

Danitol 2.4EC (Valent U.S.A.) for control of two-spotted spider on soybeans was granted a Crisis Exemption on July 24, 1998 by the Delaware Department of Agriculture. With populations building as a result of the hot, dry weather and reports of dimethoate failures again this year, it was decided that a crisis exemption was needed. Since there was no available aerial application data and researchers working with the product in peanuts strongly recommended that it be applied by ground only, the label states that Danitol should be applied with ground equipment only with adequate water for complete coverage (10-50 gallons of water per acre). In our recent watermelon trial, we used 20 gallons of water per acre and got very good control. The use rate is 16 fluid ounces per acre. Treatments should be applied when mites reach an economic threshold level of 20-30 mites per leaflet and/or 10% of the plants exhibit mite damage (light stippling not severe damage) over more than one-third of the leaves. In general, one application at 16 ounces per acre rate should provide control. However, if egg laying is heavy and mites are still active after the first application, a second application at 16 oz per acre will be needed. No more than 2 applications are allowed under the Crisis Exemption. Do not apply within 30 days of harvest and do not feed soybean forage to live stock. v

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

Weather Still Improtant Factor for Grain Markets.

Weather continues to be an important factor for the commodity markets, howerver, its impact on soybeans is now greater than for corn. Approximately, 60% of the U.S. Corn crop has entered the pollination stage. Beneficial rains and cooler temperatures in much of the corn belt has taken its toll on December corn futures. Overnight Project A December corn futures closed at $2.26 per bushel on July 29, 1998.

While the Southeast and Southwest will suffer significant yield losses from the drought they are experiencing, only 6% of the soybean crop is produced from Florida to Texas. Therefore, a large production loss in this part of the U.S. production region will hardly dent total U.S. soybean production. Overnight Project A November soybean futures closed at $5.68 1/4 on the same date.

The National Weather Service 6 to 10 day forecast is not calling for any excessive heat in the corn belt for this coming week. Export inspections are currently running slightly ahead of expectations. Commodity markets are currently said to be oversold with farmers continuing to hold their long cash positions. Perhaps we will see a

slight rally based upon the weekly export report and tight farmer holding.v

Drought Effects on Field Crops Richard W. Taylor, Extension Agronomist ; rtaylor@udel.edu

Non-irrigated crops are facing serious problems with drought. I’ve seen a number of dryland corn fields where the ears have turned down and the plants are fired from soil-line to tassel. These fields are essentially done. If for marketing purposes you need to estimate yield, count the number of plants with filled ears per 17 and 1/2 feet of row (assuming 30-inch rows) in a number of locations across the field. Take the average of these numbers and multiply by 1,000 to get number of harvestable ears per acre. Next, examine 20 or more typical ears and count and then determine the average number of rows per ear. Then count and determine the average number of kernels per row. Multiply the average number of rows per ear times the average number of kernels per row times the number of ears per acre. Finally since these kernels are likely to be smaller than normal, divide the result (kernels per acre) by 2,250 (kernels per pound) to get pounds per acre and then divide that by 56 to get your estimate of bushels per acre. As with any estimate of yield, the number is only as good as your sampling and estimates of the components of yield.

If you are irrigating corn, keep in mind that depending on growth stage corn is using between 0.25 and 0.35 inch of water per day. But, that translates into 1.75 to 2.45 inches per week. To maintain maximum yield potential, you need to be applying that much or more each week. Even after corn reaches the hard dough stage, it will still need water until the black layer forms.

For dryland soybeans, the picture is not yet as bleak as with many corn fields. Although I have seen fields where plants are dead or dying, in most fields this is occurring in patches according to underlying soil conditions. Rain is expected by the end of this week and if it arrives it will help keep the remaining plants alive. Yield potential are being impacted because the total number of flower sites are being reduced since the plants will never reach full height. The beans can still partially compensate if the drought breaks because they can set more pods and the seed size can increase above the norm. If the drought continues until flowering is complete, yields will be severely reduced since most of the drought stressed plants I have seen have not set very many pods at this time.

Irrigation strategies for soybeans were covered in a previous week’s issue. Refer back to that for details.v

 

Watermelon Twilight Meeting

Wednesday, August 12, 1998

5:30 p.m.

At the University of Delaware Research & Education Center

Route 9, Georgetown, Delaware

Sponsored by the Universities of Delaware and Maryland

 

 

The twilight meeting this year will include:

3 A 25 variety seedless watermelon variety trial. Red and yellow flesh varieties as well as icebox and large, oblong seedless are included in the trial.

3 MELCAST, a weather-based fungicide application model for control of gummy stem blight and anthracnose on watermelon trial. This model was evaluated on research stations and growers fields in Maryland and Delaware in 1996, 1997 and 1998. Environmental favorability indices (EFI) were determined from current weather data. Sprays are applied when EFI accumulate to the threshold value of 30. Compared to plots sprayed weekly, plots sprayed according to MELCAST received two and three fewer fungicide applications in 1996 and 1997, respectively. Despite receiving fewer sprays, disease severity was the same in plots sprayed weekly or according to MELCAST where on site weather was used. Weather stations have been set up in grower's fields for the 1998 growing season and EFI data collected three times per week. Growers can access this information by fax, phone or the internet. The EFI Values are also posted each week in the Weekly Crop Update Newsletter. As researchers, we are very interested in your thoughts on this system. We would like to know if you are using the system, and what you like and dislike about the model.

3 In recent years, spider mite management in watermelons has become increasingly difficult due to improper timing of pesticide applications, lack of effective miticides and the use of cultural management systems which favor mite development. The following topics will be highlighted: mite populations under different management systems (every row rye, windbreak rye, and no rye), timing of miticide applications, and promising new materials for mite control.

University of Delaware and Maryland Specialists and Agents will be on hand to answer questions concerning problems you may be experiencing this year. We invite you to visit the plots and join us for dinner.

The meeting will begin at 5:30 p.m. followed by an "Emings" dinner at 6:00 p.m. Please call Edna Marvil at 302-856-7303 by August 10, 1998 to register for the meeting. We will need to verify the number for dinner by the 10th

Upcoming Events…

August 12, 1998

Farm & Home Field Day

Time: 8:30 a.m. - 1:00 p.m.

Location: U of D Research & Education Center, Georgetown

For More Information: Contact the REC at 303-856-7303.

August 12, 1998

Watermelon Twilight Meeting

Time: 5:30 p.m.

Location: U of D REC

For More Information Contact Edna Marvil at 302-856-7303.

August 26, 1998

Irrigation Field Day

Time: 9:00 a.m. - Noon.

Location: Thurman Adam's Farm

For More Information: Contact Mabel Hough at 302-856-7303.

September 15, 1998

Recycling of Pesticide Jugs

Time: 1:00 p.m. - 4:00 p.m.

Location: Sussex County Soil Conservation District Equipment Yard

For More Information: Contact DDA Pesticide Section at 1-800-282-8685

 

 

Week of July24 to July 31

Rainfall:

None.

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

Air Temperature:

Highs Ranged from 93 F on July 29 to 82 F on July 26.

Lows Ranged from 73 F on July 24 to 60 F on July 27.

Soil Temperature:

84 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:

Andy Turner

Student - University of Delaware

Ryan Jost

Graduate Student - University of Delaware

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.