Posts Tagged ‘20:22’

Late Blight on Tomato Confirmed in Baltimore County, MD

Monday, August 20th, 2012

Kate Everts, Vegetable Pathologist, University of Delaware and University of Maryland; keverts@umd.edu

Late blight on tomato is now confirmed in Maryland (Baltimore County). We do not yet know what strain or genotype it is. Until additional information is available, growers should assume that both tomatoes and potatoes are at risk. The pathogen is very aggressive and can complete its life cycle and sporulate in as little as 7 days. Tomato growers should scout their crop aggressively and modify their spray program. Conventional growers should add translaminar fungicides, which can move into and through leaves are more effective than a protectant only program. The following are some fungicides that have performed well on tomato in our region. Growers should apply them with a protectant and rotate among them based on rotation of products that are in a different FRAC grouping.

  • Curzate–3.2 to 5.0 oz 60DF/A
  • Forum–6.0 fl oz 4.18SC/A
  • Presidio–3.0 to 4.0 fl oz 4SC/A
  • Previcur Flex–1.5 pt 6F/A
  • Ranman–2.10 to 2.75 fl oz 400SC/A
  • Reason–5.5 to 8.2 fl oz 500SC/A
  • Revus Top–5.5 to 7.0 fl oz 4.16SC/A
  • Tanos–8.0 oz 50WG/A

The best option for organic growers is an OMRI approved copper product. While research results indicate that copper is the best available option in organic production, remember that it is a protectant. That means it must be present on tissue to work. Keep protecting plants with repeated applications as new tissue forms.

Different products are available on potato. Please refer to Maryland, Extension Bulletin 236 (in Delaware, Extension Bulletin 137) for additional information.

Because this disease can spread rapidly by air, advise home gardeners with infected plants to use fungicides – or to kill their plants and bag them or place them under a tarp. This will avoid allowing the spores to spread to neighboring farms.

Watermelon Downy Mildew Altert!

Monday, August 20th, 2012

Kate Everts, Vegetable Pathologist, University of Delaware and University of Maryland; keverts@umd.edu

Downy mildew on watermelon was confirmed in Wicomico County, MD today. When downy mildew is present, watermelon growers need to modify their spray programs because the materials that are typically used for managing more common diseases are not effective on downy mildew. Growers should add additional materials to their spray program. Do not delay sprays because preventative applications are much more effective than applications made after disease is detected. Sprays should be applied on a 7-day schedule. Remember that materials with different Modes of Action (FRAC groups) should be alternated.

The following products have been effective on cucurbit downy mildew in our area. They should be tank-mixed with a protectant fungicide such as chlorothalonil.

● Ranman (2.10 to 2.75 fl oz. 400SC/A, see label for details, do not apply with copper);

● Presidio at 3.0 to 4.0 fl oz 4SC/A

● Previcur Flex at 1.2 pt 6F/A

Other materials for that are good when used in a tank mix or in alternation are

● Tanos at 8.0 oz 50DF/A

● Gavel at 1.5 to 2.0 lb 75DF/A (Gavel contains mancozeb, which is a protectant, and does not need a tank-mix partner)

● Curzate at 3.2 oz 60DF/A

Alternatively Presidio may be applied through drip irrigation. See label for additional details and application information.

Consult the Commercial Vegetable Production Recommendations for further information on resistance management and available fungicides (in Maryland, Extension Bulletin 236 and in Delaware, Extension Bulletin 137).

WCU Volume 20, Issue 22 – August 17, 2012

Friday, August 17th, 2012

PDF Version of WCU 20:22 – August 17, 2012

Alerts Added August 20
Watermelon Downy Mildew Alert!
Tomato Late Blight Confirmed in Baltimore Co., MD

Vegetable Crops
Vegetable Crop Insects
Pumpkin Downy Mildew Alert!
Poor Fruit Set in Pumpkins
Stink Bugs are Bad in Some Tomato Fields – But it is Not BMSB

Agronomic Crops
Agronomic Crop Insects
Charcoal Rot of Soybeans
Grain Marketing Highlights

Announcements
Extension Vegetable & Fruit Program Open House – August 21
Delaware Soybean Field Day – August 22
UD Corn Hybrid Trial Tour & Twilight Meeting – August 29
UD Field Day for Sustainable and Organic Agriculture – September 13
Workshops for Farmers with Drought-Plagued Fields – September 17
2012 Delmarva Poultry Conference – September 26

Weather

2012 Delmarva Poultry Conference

Friday, August 17th, 2012

Wednesday, September 26, 2012
Ronald E. Powell Convention Center
Ocean City, MD

7:00 – 8:00 am REGISTRATION/CHECK-IN

8:00 am Switchgrass as a Litter Alternative
Bill Brown, University of Delaware
Jennifer Timmons, University of Maryland

8:25 am Managing Water for Performance
Susan Watkins, University of Arkansas

8:55 am Ten Steps to Drier Houses and Better Paw Quality
Jesse Campbell, Auburn University

9:25 am Vegetative Environmental Buffer Update
Jim Passwaters, Delmarva Poultry Industry, Inc.

9:45 am Break/Refreshments/Exhibits

10:15 am Considerations for Attic Vent Installation
Jody Purswell, USDA-ARS

10:50 am Infectious Laryngotracheitis Disease Prevalence Patterns
Dan Bautista, University of Delaware

11:15 am Infectious Laryngotracheitis Control Strategies
David Shapiro, Perdue Farms, Inc.

11:40 am Using Technology to Enhance Management Decisions
Dan Goss, Verible

12:05 pm Flock Supervisors’ Award

12:15 pm Lunch and Exhibits

1:30 pm Solar Energy for Poultry Farms
Jim Glancey, University of Delaware

2:00 pm Poultry Grower Experiences with Solar Energy
Dan Heller, Flintrock Farm

Robbie Issacs, Issacs Farm

Terri Wolf King (unconfirmed), Cornerstone Farm

2:45 pm LED Lights – New Technology in Lighting
Susan Watkins, University of Arkansas

3:15 pm Poultry House Water Supply
Jesse Campbell, Auburn University

A block of rooms has been reserved at the Princess Bayside Beach Hotel (Standard: $55 + tax, Bayfront efficiency: $69 + tax)
800-854-9785   www.princessbayside.com

Rooms are reserved under:
Delmarva Poultry Conference
Reservations must be made BEFORE August 27, 2012

Registration form and additional information is online at: http://agdev.anr.udel.edu/weeklycropupdate/wp-content/uploads/2012/08/2012DelmarvaPoultryConference.pdf
or contact:
Lisa Collins: (302) 856-2585 x702 or lcollins@udel.edu

UD Corn Hybrid Trial Tour & Twilight Meeting

Friday, August 17th, 2012

Wednesday, August 29, 2012     4:00-7:30 p.m.
Dickerson Farms
1730 Bayside Drive, Dover, DE

Farmers, Crop Advisers, and all those interested are invited to attend.  The corn hybrid plots will be open for viewing at this irrigated location starting at 4:00 PM. Extension specialists and agents will be on hand to discuss insect pest management in corn, disease identification, weed control, and fall nutrient management.

Dinner will be provided therefore RSVP is required.

Please RSVP by calling (302) 730-4000 or email Phillip Sylvester: phillip@udel.edu

CCA, DE Nutrient Management, and DE Pesticide credits will be available.  Contact Phillip Sylvester, Extension Agriculture Agent, at (302) 730-4000 with any questions.

Grain Marketing Highlights – August 17, 2012

Friday, August 17th, 2012

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

World Production Declines Bolster Commodity Prices
During the first of the week corn and soybean prices slackened off due to the lack of fresh news concerning new crop corn and soybeans. The Weekly Crop Progress report lowered U.S. corn crop conditions in the fair category by one point and increased corn rated as very poor by one point. Soybeans rated poor dropped one point. Soybeans rated good were increased one point above last week’s ratings. Weekly export sales for the week ending August 9 were reported to be bearish for both corn and soybeans.

Commodity traders appear to be waiting for harvest to progress to see if USDA’s August production estimates will hold true or eventually be lowered. By Wednesday commodity futures were bidding up due to production concerns for corn in China and the EU buoyed by a weakening U.S. dollar.

Marketing Strategy
These markets continue to be extremely volatile. Declines in U.S. production estimates could still occur impacting the supply of corn going into the ‘12/‘13 marketing year. Simultaneously, demand (use) can be cut further, hopefully rationed by the markets rather than government intervention. In USDA’s August 10 supply and demand report USDA slashed projected supply for the ‘12/‘13 marketing year by a total of 2.028 billion bushels from their July estimate. Total use was reduced by 1.495 billion bushels from July. Ending stocks were cut by 533 million bushels from the previous month. The same hold true for U.S. soybeans. USDA reduced the projection for total U.S. soybean supply by 378 million bushels. Projected use was reduced 363 million bushels. Ending stocks were reduced by 15 million bushels from July estimates. With the near pipeline ending stocks estimates for the ‘12/‘13 marketing year it becomes obvious that further cuts in demand will be necessary if yields do not achieve the August 10 estimates. This week’s U.S. Drought Monitor does not indicate any improvement in weather conditions in the Corn Belt (http://droughtmonitor.unl.edu/).

Although new crop corn and soybean prices are currently trading lower than their recent highs one has to consider that harvest sales still make sense. Both new crop corn and soybean futures contracts are inverted indicating that there is no carry in these markets at the present time. From the December ‘12 new crop corn futures contract to the July ‘13 contract, the corn market is inverted by 20 cents per bushel. It has been suggested that getting needed corn supply has alternatives in the world market, albeit not as good as earlier projections indicated. From the November ‘12 new crop soybean futures contract to the July ‘13 contract, the soybean market is inverted by almost $2.00 per bushel. This means that commercial traders believe that the U.S. could run out of soybeans before the 2013 crop is harvested. This all portends to these markets remaining extremely volatile well into the 2013 cropping season. At the present time there are no definitive answers to making sales decisions. Nothing can be considered as normal. The August supply and demand estimates are subject to change when USDA’s September 12 supply and demand report rolls around, as were the June and July projections.

Dec ‘12 corn futures achieved a life-of-contract high on August 10 at $8.49 per bushel. Nov ‘12 futures prices achieved a life-of-contract high at $16.91 per bushel on July 20 and again on July. Currently, Dec ‘12 corn futures are $8.08; and Nov ‘12 soybean futures are $16.28 per bushel.

For technical assistance in making grain marketing decisions contact Carl L. German, Extension Crops Marketing Specialist.

Charcoal Rot of Soybeans

Friday, August 17th, 2012

Nancy Gregory, Plant Diagnostician; ngregory@udel.edu

Charcoal rot was diagnosed on soybean plants in early August, much earlier than we normally see this disease. We usually see charcoal rot near maturity, and these plants had small pods about ¾ inch in length. Charcoal rot is a stem rot caused by Macrophomina phaseolina, a soil-borne fungus with a wide host range, infecting many bean species and corn. Charcoal rot often shows up in Delaware fields in the late summer season, as soybeans mature, especially in drought stressed beans. Plants may show a loss of vigor or smaller than normal leaves. Leaflets may yellow, but stay attached at the petioles. Dark lesions may extend up the stem from the soil line. Eventually, the fungus colonizes the water-conducting tissues of the bean stems, and plants die. The fungus produces small survival structures called microsclerotia; I think of them as small rubber-band-balls of fungal strands. The numerous small dark microsclerotia look like charcoal dust, giving the disease its name. These microsclerotia can survive in soil and debris for several years; however, they do not survive well in wet soils. The fungus can survive on seeds in small cracks. Often, infections occur early, when soil moisture is good, and symptoms become obvious late in the season as plants become stressed from drought. To control, rotate away from fields that have been heavily infested, for at least two years. Irrigation and cultural practices such as good fertility and average seeding rates should help avoid the stress that brings on symptoms of dieback. There are no good resistant varieties, but breeding work is ongoing. Foliar fungicides are not effective for controlling charcoal rot.

Agronomic Crop Insects – August 17, 2012

Friday, August 17th, 2012

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

Alfalfa and Grass Hay Crops
Continue to watch for defoliators in grass hay crops and alfalfa. It is important to catch populations before significant damage has occurred and when larvae are small. In addition to checking labels for rates, be sure to check for all restrictions including but not limited to comments on control under high populations and size of larvae; days to harvest and forage/silage restrictions. Be sure to also scout alfalfa for leafhoppers. Once yellowing has occurred, significant in season damage and long term stand damage has already occurred

Soybeans
Economic levels and hot spots of high levels of corn earworm larvae continue to be found full season and double crop fields in Kent and Sussex counties but they are not present in every field. In general, most larvae are small to medium in size, and occasional large larvae can be found. Since population levels vary from field to field, the only way to know if you have an economic level will be to scout all fields. Remember, corn earworms can feed on the foliage and blossoms as well as the pods. Although there is no threshold for corn earworm feeding on flowers or leaves, data from North Carolina has indicated that feeding on flowers can result in reduced yields by delaying pod set. When looking at foliage feeding by corn earworm, you will need to use defoliation as well as the presence of worms to make a decision (again – there is no worm threshold available for leaf and/or blossom feeding). Once pods are present, the best approach to making a decision on what threshold to use for corn earworm is to access the Corn Earworm Calculator developed at Virginia Tech (http://www.ipm.vt.edu/cew/) which estimates a threshold based on the actual treatment cost and bushel value you enter. Remember, this threshold calculator was developed only for corn earworm.

Be sure to scout for stinkbugs in fields that are in the pod development and pod fill stages. Economic damage is most likely to occur during these stages and a combination of species can be found in fields throughout the state. You will need to sample for both adults and nymphs when making a treatment decision. Available thresholds are based on beans that are in the pod development and fill stages. As a general guideline, current thresholds for native stink bugs are set at 1 large nymph/adult (either brown or green stink bug) per row foot if using a beat sheet, or, 2.5 per 15 sweeps in narrow-row beans, or 3.5 per 15 sweeps in wide-row beans. We do not have a threshold for brown marmorated stink bugs (BMSB).

We continue to find a significant number of defoliators including beet armyworm (BAW), fall armyworm, yellow striped armyworm, green cloverworm and grasshopper in double crop and a few full season fields. All of these insects are defoliators and you will need to use percent defoliation to make a treatment decision. There are no available thresholds for the number of the above insects per sweep. Remember, that in addition to defoliation, grasshoppers can feed on and/ or scar pods. In full season soybeans in the pod fill stage, the threshold is 10-15% defoliation. Remember, double crop soybeans cannot tolerate as much defoliation since they often do not reach the leaf area index needed for maximum yields. As a reminder, the pyrethroids will not provide effective control of beet armyworm so a product labeled for beet armyworm in soybeans will be needed if defoliation is present.

Soybean looper populations are also starting to increase. Identification can be difficult because although there is a “black footed” phase of the soybean looper there is also a “green phase” that can be confused with cabbage loopers. One characteristic that might help is the presence of microspines on soybean loopers that are not present on cabbage loopers; however, you will need high magnification to see the microspines. Soybean loopers are a migratory pest, difficult to control and pyrethroid resistance has been documented in states to our south.

Stink Bugs are Bad in Some Tomato Fields – But it is Not BMSB

Friday, August 17th, 2012

Jerry Brust, IPM Vegetable Specialist, University of Maryland; jbrust@umd.edu

I have seen a great deal of stink bug damage to tomato fruit this year-more than usual (Fig. 1). The fruit has the characteristic white spots that when peeled back reveal spongy white areas. As the fruit turns red these white areas turn yellow (Fig. 1). When adults, or especially nymphs, feed on the fruit they create a star burst pattern in the surface of the fruit. I guess the surprise is that I have found very few if any Brown marmorated stink bugs (BMSB) in any of these tomato fields. Almost all of the stink bugs have been brown stink bugs (Euschistus spp), although lately (last 2 weeks) I have seen more green stink bugs. There have been very few reports or observations of BMSB being much of a problem so far this year in vegetables. Adult brown stink bugs are grayish-yellow to light brown with dark punctures on their back (Fig. 2). They DO NOT have two white spots on their antenna as do BMSB. Adults overwinter in woods, fence rows and under the bark of trees. A female oviposits a total of about 60 eggs over the summer. The nymphs, which are pale green, develop through five instars and require about one month for development. Because the adults are strong fliers they rapidly can move between hosts. Brown stink bugs are very difficult to scout for and often the only thing that is seen is the damage they cause to large green or ripening fruit. Stink bugs are difficult to control even when found as it takes several applications of insecticide to reduce their numbers (see the Commercial Vegetable Production guide for recommendations). Some of the most heavily fed upon fruit had very dark areas that when cut into appear as a dry rot (Fig. 3). What microorganisms are in this dry rot area is something we are looking into. It appears that our native stink bugs can inject microorganisms almost as readily as do BMSB when they feed.

Figure 1. Stink bug feeding on tomato, yellow areas when cut reveal spongy white cells

Figure 2. Brown stink bug, Euschistus, spp.

Figure 3. Internal dry rot caused by very heavy stink bug feeding

Poor Fruit Set in Pumpkins

Friday, August 17th, 2012

Gordon Johnson, Extension Vegetable & Fruit Specialist; gcjohn@udel.edu

Each year we see pumpkin fields with poor fruit set or fruit carry. Remember that in larger pumpkin sizes, each plant will only carry 1-2 fruits. The large vining plants also need considerable space – 25 to 50 square feet per plant. While planting Jack-o-lantern types at higher densities might at first seem to be a way to achieve higher yields, interplant competition will increase and you can decrease fruit carry because of this competition.

Too much available nitrogen can also delay pumpkin fruit set so that many of pumpkins that are produced do not reach maturity in time. Pumpkins do not normally need more than 80 lbs/acre N to grow a crop. Anything above 100 lbs/acre N will cause the pumpkins to put on excessive vine growth and limit fruiting.

A major reason for poor fruit set in some fields this year is high temperatures during flowering in July. Day temperatures in the 90s or night temperatures in the high 70s will cause flower and small fruit abortion. For pumpkin growers that do wholesale and start shipping right after Labor Day, this will limit early pumpkin availability. Varieties vary considerably in their ability to tolerate heat and to set under hot conditions. Inadequate irrigation and excessive water stress can also reduce fruit set, increase abortions, and reduce fruit carry. High temperatures and water stress reduce photosynthesis and the ability of the plant to carry fruits. Drought can also cause a higher than normal male/female flower ratio, thus affecting the amount of fruit per plant.

Another major factor that will reduce fruit set is poor pollination. Misshapen fruit can also result from inadequate pollination. A pumpkin plant has both male and female flowers and the first female flower opens one week after the first male opens. The flowers only last a few hours, blooming at dawn and closing later in the morning but well before noon. Pollinators need to be active during this short period.

Native pollinators can be very effective in pollinating pumpkins and some research has shown that most of the fruit set is occurring because of these native pollinators. In particular, bumblebees and squash bees are active in pumpkins. The squash bee is of particular interest because it has evolved along with pumpkins and squash in the Americas and is dependent solely on pollen from pumpkin and squash plants.

Other research has shown that honeybees do provide additional pollination benefits above what native pollinators are providing. In research from Illinois, Walters and Taylor found that while pumpkin fruit number was not increased with the addition of honeybees, pumpkin weights and size were increased significantly.