Volume 12, Issue 19                                                                    July 30, 2004


 

Text Box: Vegetables

 

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

 

Beet armyworms on the Eastern Shore (Tom Kuhar. VPI)
We have seen some infestations of beet armyworm on various crops on the Eastern Shore. In addition, we are catching relatively high numbers of moths at our black light trap in Painter, VA. Beet armyworms will usually occur in high numbers on plants. Suspect beet armyworm if feeding damage tends to be concentrated around the growing point of plants. Color patterns of the larvae (caterpillars) can be quite variable. Young larvae are pale green or yellow, but acquire pale, then dark stripes as they get older and larger. Large larvae tend to be green dorsally and possess a lateral dark stripe the length of their body. Sometimes larvae are very dark. The body is completely devoid of hairs and spines. They are often found in groups and there is often webbing with droppings. The major problem with beet armyworms is that they are difficult to kill. Historically, the larvae have been resistant to the pyrethroid insecticides (Warrior, Ambush/Pounce, Asana, Baythroid, Mustang, Capture, etc.), and most of the organophosphates. In 2002 (our last big beet armyworm year in Virginia), my lab tested some newer insecticides along with some of the standards from the past for efficacy against beet armyworm in bell peppers. The best control was achieved with Avaunt, followed by Intrepid, SpinTor, and Lannate. The Bt products provided some control of beet armyworm, but are most effective when applied to smaller larvae. Efficacy trials conducted by Dr. Ames Herbert (Tidewater AREC) on soybeans showed that Steward (indoxacarb) was the best material for beet armyworm control. Steward contains the same active ingredient as Avaunt (labeled on vegetables).

 

Lima Beans –Continue to scout fields as soon as pin pods are present for lygus bugs and stinkbugs. Treatment should be considered if you find 15 adults and/or nymphs per 50 sweeps. Lannate, Capture or Mustang can be used if both species are present. The higher labeled rates of Capture (4 oz/A) and Mustang (4.3 oz/A) will be needed if stinkbugs are the predominant insect present. With the recent increase in corn earworm trap catches, you should also start scouting fields with pin pods for corn earworm larvae.  A treatment will be needed if you find one corn earworm larvae per 6 ft of row from late flat pod stage until harvest.

Melons - Continue to scout all melons for aphids, cucumber beetles, and spider mites. Although spider mites have crashed in some fields, we continue to find an occasional field with economic levels.  Since beetles found now are causing damage to rinds, be sure to watch fields carefully and treat as soon as you

see an increase in the populations.  Be sure to watch for bees foraging in the area and avoid insecticide applications on blooming crops.

Peppers - Be sure to maintain a 5-7 day spray schedule for corn borer control. Since corn earworm populations are starting to increase in some locations, you will also need to consider treating for this pest. Remember, Orthene provides poor corn earworm control, so you will need to add a pyrethroid to the mix.  You will also need to consider a treatment for pepper maggot. Continue to scout for beet armyworm, especially if fields are weedy. As indicted above in Tom Kuhar’s article, 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 consider this pest when making you 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 may need to consider a combination of a pyrethroid plus Lannate, Larvin or Lorsban for the first 2-3 silk sprays.

Spring Pickling Cucumber Variety Trial – Ed Kee, Extension Vegetable Crops Specialist; kee@udel.edu

 

In our spring pickling cucumber variety trial, we could discern no real differences between varieties relative to resistance reaction to Downy mildew.  This can probably be directly attributed to the high level of innoculum and the perfect conditions for the development of the disease following a six-inch rain.  The Ridomil/Gold/Bravo did maintain the vines, but the impact of the disease had already done its damage on the foliage's ability to support the crop.   Hence yield reductions and a lot of crooks and nubs.

 

Early reports of Ridomil sprayed in a seven-inch band at planting indicate early control is being achieved.  Of course, a fungicide program will need to be continued.

 

 

  

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

 

Downy mildew in lima beans has not been confirmed yet in commercial limas in DE. Labels for the two section 24 (c) fungicides mentioned last week Ridomil Gold/Copper and Phostrol are included if they are needed - htttp://www.rec.udel.edu/update04/Updatepdf.htm

 

The following link will also show the effectiveness of both fungicides in last years fungicide test http://www.udel.edu/IPM/pmr/limabeanfungicide2003.pdf.    Conditions are favorable for downy mildew infection at the present time.  If limas are in bloom or have set pods, preventative sprays, are recommended. Both races E and F were present last season and we saw the most damage from race F on C-Elite Select and race E on M-15 and Sussex. Cypress was infected by race F, but there was not as much effect on yield as best we could tell.

 

Late Blight Advisory.

 

Disease Severity Value (DSV) Accumulation as of July 28, 2004 is as follows:

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

 

Date

 

Daily DSV

 

Total DSV

Spray Recommendation

6/26-30

0

87

10-day

7/1

2

89

10-day

7/4

2

91

10-day

7/7

2

93

10-day

7/11

1

94

10-day

7/12

5

99

7-day

7/13

2

101

7-day

7/14

2

103

7-day

7/17

10

113

5-day

7/19

19

114

5-day

7/22

2

116

7-day

7/23

2

118

7-day

7/24

9

127

7-day

7/26

5

132

7-day

7/27

11

143

5-day

 

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.

 

 

 


Text Box: Field Crops

 

 

 

 


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

 

Soybeans –  In most cases, it appears that spider mite populations have crashed due to the recent weather conditions. However, be sure to check fields if you still suspect that mites are present, and apply a treatment if you can find 20-30 mites per leaflet or 10% of plants with 1/3 or more leaf area damaged.

You should continue to scout on a weekly basis for soybean aphid. We continue to find low levels in all three counties. They prefer somewhat cooler temperatures, 68-77°F, so we could see an increase with the recent cooler temperatures. However, they are also subject to predation by several insects like

lady beetles, lace wings and others.  Hopefully, a combination of hot weather and action by these natural enemies will prevent economic aphid levels, but you  won’t know unless fields are monitored. You should sample both full season and double crop fields – although double crop fields will be at more risk at this time. 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 1000-1500 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 did conduct a limited corn earworm survey of corn fields in the state and results indicate that local populations are relatively low (2-26% of the ears infested). However, the Virginia survey indicates that their populations are higher than normal in some areas. Their regional averages range from 13.2-53.5% infested ears.  The following is a report of survey results from Ames Herbert, VPI:

 

Annual field corn survey reveals moderate to high potential for corn earworm problems in soybeans, cotton and other crops in Virginia (Ames Herbert, VPI):
We have just completed our annual survey of field corn to determine corn earworm infestation levels and make predictions of what is to come. Thanks to the many VCE Agents and other faculty for their participation (Dr. Tom Kuhar, Entomologist, ESAREC; and VCE ANR Agents Paul Davis, Keith Balderson, David Moore, Mac Saphir, Matt Lewis, Sam Johnson, Glenn Chappell). Together, we sampled 7,250 ears from 145 fields in 29 eastern counties during the period from July 14 to July 20. We did the survey about 10 days earlier this year because the corn crop is so advanced compared with most years. Compared with 2003, infestation levels are either about the same (19.9% in the Northern Neck compared with 19.3% in 2003; 27.2% on Eastern Shore compared with 29% in 2003), or higher (35.3% in the mid eastern counties compared with 28% in 2003; 53.5% in the southeast compared with 49% in 2003). Only in the northernmost survey counties (King George and Caroline) was the level lower (13% compared with 25% in 2003). These numbers mean that we can expect moderate to high pressure in soybean, cotton and other crops when this earworm population leaves corn. Also, when we did the survey we noted that many of the larvae were large or had already exited the ears. This means we can expect to see the moth flight begin soon. According to Dr. Jack Bacheler at NC State, the moth flight has already begun in southern North Carolina. In Virginia, our blacklight trap catch is still very low, but is just in the last few days beginning to increase.  It is always
dangerous to make predictions, but based on what we are seeing, we may see egg thresholds in cotton within the next week. Folks should begin scouting cotton fields for eggs later this week. For soybean, it takes more moth activity and longer for thresholds to develop. Soybean fields are not in any danger for a few weeks, stay tuned to future advisories to get a heads up on when field scouting should begin. Keep in mind that infestation levels in corn can be misleading. Even with high levels in corn, a lot of rainy weather, especially heavy rains, can kill a lot of the corn earworm pupae in the corn fields before they can mature into moths. Wet years usually have less pressure, especially in soybean. But like politics, all weather is local. There are still some areas of the state where fields are relatively dry and corn earworm survival will be good.

 

Therefore, in Delaware, we could experience a higher than normal migratory population this year. We are also just starting to see a spike in corn earworm black light trap catches. Therefore, you should begin sampling fields in early August

(especially double crop fields)  since early detection can help you make the most cost effective control decision.

 

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

 

 

 

 

Downy mildew on soybeans is widespread this season. It is a minor disease and at best can be determined causes no economic loss at the level we are seeing in the field. This downy mildew is caused by the fungus Peronospora manshurica, which is different from  the fungi that cause downy mildew on curcurbits (Pseudoperonospora cubensis), lima beans (Phytophthora phaseoli), and spinach (Peronospora diffusa).

 

 

  Photos courtesy of the Southern Soybean Disease Workers

 

Septoria brown spot is another very common and widespread foliar disease of soybeans now. It begins in the lower canopy and can move higher when weather conditions favor the fungus and the cultivar is susceptible. Unless it extensively infects the upper canopy during pod fill it is thought to cause little or no yield loss.

 

 

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

 

U.S. Crop Conditions Point to Record Crops.
Crop ratings have improved again this week for U.S. corn and soybeans as grain analysts continue to speculate production of both crops could hit record levels, 11 (+) billion bushels for corn and 3 (+) billion bushels for soybeans. The only year over the past 18 years when ratings for this time of year were higher was 1994. It is duly noted as simply amazing that these ratings continue to improve at the time of year when crop conditions usually decline. A side note, although things look excellent in the heart of the Corn Belt three states are known to be experiencing crop maturity that is lagging way back: North Dakota, South Dakota, and Minnesota. The corn crop in those states is just now entering pollination.

General Comments.
Corn futures are technically oversold and are due for a bounce, therefore; we are likely to see some price strength bidding into new crop corn prices. The extent of any price strength will hinge upon the amount of rainfall we get through the weekend. USDA's projection for U.S. corn exports at 1.950 billion bushels is being called into question because weekly levels are achieving the 48 million bushels per week necessary to hit the projection.

Soybean futures are also expected to bid higher due to the extent of the sell off that we have seen recently, with weekend weather possibly putting a damper on the technical bounce. The June Census Crush was reported near expectations at 109.4 million bushels. Meal and oil stocks were both reported below expectations this week continuing to indicate strong domestic demand.   

Wheat futures should experience a positive gain in the near term based upon export sales exceeding expectations. We are continuing to outpace last year's level of exports.

Market Strategy.
With the recent sell off in the corn, soybean, and wheat pits it is to be advisable to stand aside placing additional sales on hold. It is quite possible that early harvested corn on the Eastern Shore could see some premium basis offers. This will present an opportunity for some unpriced new crop corn to move into the priced column. The August Crop Report will give the trade a far better reading on the size of this year's U.S. corn and soybean production potential. Weather patterns, including growing degree days (or lack thereof), and the potential for an early frost occurrence will eventually dictate the crop size.

 

 

UPCOMING MEETINGS:

 

Attention Delmarva Beef Cattle Producers!

 

 

 

 

 

The Delmarva Cattlemen’s Association and the University of Delaware Cooperative Extension have some exciting upcoming events planned just for you!  Please consider joining us for some of these opportunities.

 

Tues. August 3rd- Grazing Tour- Bill Edwards Bison Farm, Dorchester Co. MD- Bill is a very intense manager of Eastern Gammagrass for both grazing and hay.  Eastern Gammagrass is very drought tolerant, but wet soil friendly grass.  Please call the Extension Office at (302) 730-4000 or truehart@udel.edu to RSVP by Friday,

July 30th and for more details!  A car pool will be arranged if interest warrants.

 

Mon. August 12th- Grazing Tour- University of Maryland Wye Angus Farm- Queenstown, MD- Planning for the establishment of warm season grasses for grazing and their management.  Please call the Extension Office at (302) 730-4000 or truehart@udel.edu to RSVP by Friday,

August 6th and for more details!  A car pool will be arranged if interest warrants.

 

Sat. August 28th- Beef and Dairy Beef Quality Assurance Training- 10:00 a.m.- 2:30 p.m.- lunch provided, minimal registration fee per operation- location to be announced.  Scott Wright, Pennsylvania Beef Quality Assurance Coordinator will be joining us to lead this training.  Completing Quality Assurance training is simply part of good management in any livestock industry.  The goal of Quality Assurance training is to assure the consumer that all cattle shipped from a beef/dairy beef production unit are healthy, wholesome and safe and that their management has met FDA, USDA and EPA standards.  Please consider joining us for this valuable and important training.  Contact the Extension Office at (302) 730-4000 or truehart@udel.edu for more information.

 

Sincerely, Susan Truehart Garey, Extension Agent, Animal Science, University of Delaware

 

Text Box: Weather Summary
 
 
 

 


http://www.rec.udel.edu/TopLevel/Weather.htm

 
Week of July 23 to July 29, 2004

Rainfall:

0.04 inches: July 23

0.02 inches: July 24

0.06 inches: July 25

0.02 inches: July 26

0.04 inches: July 27

0.04 inches: July 28

0.02 inches: July 29

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

 

Air Temperature:

 

Highs Ranged from 88°F on July 27 to 72°F on July 24.

Lows Ranged from 71°F on July 28 to 68°F on July 26.

 

Soil Temperature:

77°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.