Volume 7, Issue 14                                                                                                July 2, 1999


Vegetables

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

Carrots.

Carrot weevils are now active and sprays should be applied on a 7-10 day schedule. Three applications of Asana or Baythroid should provide effective control.

Peppers.

At the present time, all peppers that are inch in size or larger should be sprayed on a 10 day schedule for corn borer control. If Orthene is used, it will also control pepper maggot. If Lannate or a pyrethroid is used, then dimethoate should be added to the mix. 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.

Potatoes.

As we get close to harvest on the earliest planted potatoes, be sure to continue to sample for potato leafhoppers and aphids. In general, Colorado potato beetle populations are still light in most fields. Both potato leafhopper adults and nymphs can be found in fields. The treatment threshold is 1 adult per sweep or 1 nymph per 10 leaves. Provado or a pyrethroid will provide control. Aphid populations have also started to increase. At 2 weeks from harvest, the treatment threshold is 10 aphids per leaf.

Snap Beans.

Since corn borer catches remain low, snap beans will not need to be sprayed for corn borer until trap catches reach the 2 to 5 per night range in your area. At that time, processing snap beans should be sprayed with Orthene at the bud and pin stages. Fresh market snap beans should be sprayed with Lannate. 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.

Sweet Corn.

Fresh market silking sweet corn should be sprayed on a 5-6 day schedule throughout the state except in the Wyoming area where sprays are needed on a 4 day schedule. Although moth catches have been relatively low, we should start to see an increase in populations in the next 10 to 14 days. 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. Fall armyworm infestations continue to increase in whorl stage corn. Treatments should be applied if 15% of the whorls or tassels are infested with live larvae. In most cases, 2 applications of Larvin (30 oz/acre) or Warrior(3.84 oz/a) will be needed to provide control. v


Vegetable Diseases - Bob Mulrooney, Extension Plant Patholgist ; bobmul@udel.edu

LATE BLIGHT REPORT

DSV accumulations as of June 29, 1999 are as follows:

Location/

Emergence Date

DSV’s

June

27

DSV’s

June

29

Recommendation

P-Day

Value for Early Blight Prediction*

Baldwin – 4/19

74

77

5-day, mid rate

520/ 531

Jackewicz – 4/30

66

69

5-day, mid rate

468/ 479

Art Wicks – 4/26

65

69

5-day, mid rate

487/ 497

Ken/Chris Wicks – 5/3

62

66

5-day, mid rate

450/ 461

*bold is current value/ regular is previous report value.

Conditions are once again favorable for late blight. Keep on your spray schedule. Rates for early blight susceptible varieties should be in the mid to high range of the label rate. v


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 June 23-30. Any questions please call Phil Shields at (410) 742-8788 or e-mail: ps136@umail.umd.edu

EFI Values for 1999

Location

6/23

6/24

6/25

6/26

6/27

6/28

6/29

6/30

U of M, LESREC
Salisbury,MD

1

1

3

4

4

1

0

5

Wootten Farms, Galestown,MD

1

0

2

2

2

0

0

6

Mark Collins,
Laurel, DE

1

1

2

2

3

1

0

6

Vincent Farms Laurel, DE

0

1

1

2

3

0

0

5

D C Farms,
Bridgeville, DE

0

1

2

2

3

1

1

5

Balvin Brinsfield,
Vienna, MD

1

1

2

2

3

0

0

5

Charles Wright,
Mardela Springs, MD

6

1

2

0

2

0

0

5

U of D, REC Georgetown, DE

0

0

1

0

1

0

0

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


Field Crops

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

Field Corn.

Low levels of fall armyworm larvae can be found in the whorls of later planted field corn. Feeding damage will appear as large ragged holes with larvae being found deep in the whorls. No controls should be applied unless 75 to 80% of the plants throughout the field are infested with one or more worms per plant. Treatment is not recommended for silage corn. In many cases, damage will be confined to localized areas in a field so controls are often not justified. In addition, 2 applications are often needed to provide effective control in whorl stage corn. If you decide to treat for these insects, high gallonage (30 to 50 gallons of water per acre) is needed to move insecticides into the whorl. If fall armyworm is the predominant species, Lannate or Warrior will provide the best control.

Soybeans.

In addition to grasshoppers, thrips and potato leafhoppers, green cloverworm populations are starting to increase in soybeans. Small larvae produce "window-pane" feeding holes in the leaves. As larvae increase in size, the damage will appear as large holes between the veins. In general, no controls are needed prebloom unless you find 15 larvae per foot of row and 30 % defoliation. A pyrethroid will provide effective control.

Continue to sample carefully for mites feeding on the undersides of the leaves. Damage will first appear at the base of leaves appearing as white stippling on the top surface of leaves. A treatment should be applied when you find 20 to 30 mites per leaflet. Since we do not have any good miticides available for mite control in soybeans, early detection and application of control materials is critical. If dimethoate is used, high storage temperatures (greater than 95 degrees F) can reduce the effectiveness and it is very susceptible to degradation if the pH and/or iron content of the spray water are high. Buffering agents can be added to the mix to adjust for high pH and iron content. The buffering agent should be added to the spray tank before dimethoate is added. During the last two seasons, dimethoate plus a penetrant/acidifying agent ( e.g. LI-700, AD-100) applied in 20-25 gallons of water per acre has provided mite control in areas where there is no known resistance to dimethoate. Delaware and Maryland have again submitted a Section 18 request to EPA for the use of Danitol for mite control in soybeans. We will keep you posted on the progress of this label. v


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

Rain Is Making Grain
At a recent seminar held in Indianapolis, Dr. Elwyn Taylor, a nationally renowned and highly respected meteorologist from Ohio State University,
reported that the U.S. corn and soybean crop condition(s) are the best they've been in over a decade! This is reportedly true as of June 30. He went on to state, in terms of yield, that might not mean much. Historically, crop conditions in the month of August, after the crop has grown and when it enters the development stage, becomes critical in determining the potential size of the crop yield.

Meanwhile, with the phenomenal growing conditions unfolding, some market traders are now calling for a potential soybean crop of over 3 billion bushels, the largest on record! That size crop will add to a soybean surplus that has already helped push down prices of the nation's second-biggest crop to the lowest level in 24 years. U.S. soybean farmers planted 74.2 million acres of soybeans this spring, 3% more than last year's record-large acreage.

The U.S. corn crop is reportedly in an equal footing. Some traders are thinking that it is possible for the nation's '99 corn crop to top last year's 9.76 billion bushels, even though fewer acres are planted. U.S.
corn farmers planted 77.6 million acres, down 3% from last year. v



Roundup Ready in Double-Cropped SoybeansMark VanGessel, Extension Weed Specialist; mjv@udel.edu

Planting soybeans following small grains is under way. Remember to start off clean with a burndown. Trying to time the Roundup or Touchdown application to provide both "burn-down" and in-crop weed control does not work. Timing of in-crop application of Roundup Ultra or Touchdown is not as critical as with full-season soybeans. Applications from 14 to 28 days after planting resulted in similar weed control and yield in studies conducted with the Delaware Soybean Board. Check your fields about 14 days after planting because weeds not killed with the burndown treatment will be starting to re-grow. Then the second application can be made before the weeds become too large. v


Upcoming Meetings…

Lower Eastern Shore REC Twilight Meeting

July 7, 1999

6:00 p.m.

Project: No-till transplanted watermelons in a rye cover crop compared to conventional tillage.

Location: 8-Acre field at the corner of Dykes Road and Toadvine Road , SE of Salisbury, Maryland.

Directions: Turn west-southwest onto Toadvine Road from Snow Hill Road (Route 12) mile north of the Route 13 Salisbury by-pass and travel 1 mile to the field.

Alternative Directions: From South Salisbury Boulevard (Route 13), turn east onto Milford Street, south of SSU campus, travel mile to Division Street. Turn south onto Division Street, travel mile to Royal Farm Store and turn east onto Dykes Road. Travel 2 miles to field.

Sponsors:

Mike Malone & Sons, Mike and Mack: Growers

USDA-Sustainable Agriculture Research and Education (SARE) Program

Maryland Cooperative Extension, University of Maryland

Observance & Discussion: A comparison of transplanted watermelon in no-till rye with conventional moldboard plow and tillage. Trickle irrigation has been applied to both tillage methods. The two treatments have four replications. Maryland Cooperative Extension Agents and Specialists will discuss the program.

Refreshments will be provided.

For more information: 410-742-8788


                 Weather Summary

Week of June 24 to June 30

Rainfall:
0.20 inches: June 29, 1999
0.30 inches: June 30, 1999
Readings taken for the previous 24 hours at 8 a.m.
Air Temperature:
Highs Ranged from 94F on June 29 to 76 F on June 30.
Lows Ranged from 75F on June 28 to 51F on June 24.
Soil Temperature:
79F 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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