Posts Tagged ‘19:2’

WCU Volume 19, Issue 2 – April 1, 2011

Friday, April 1st, 2011

PDF Version of WCU 19:2 – April 1, 2011

In this issue:

Vegetables
Winter Temperature for Predicting Stewart’s Wilt in Delaware Sweet Corn 2001-2011
Early Sweet Corn

Fruit
Protecting Your Plasticulture Strawberry Investment
Mites and Aphids in Strawberry Plantings

Agronomic Crops
Agronomic Crop Insects
Viruses in Winter Wheat
Grain Marketing Highlights

General
New Kent Co. Ag Agent
NRCS to Deploy Technical Team to Increase Conservation in Delmarva Area
News from the Nematode Assay Service

Announcements
Produce Food Safety Training for Small Scale Growers
Sussex Soil Health and Vegetable Production Workshop – April 7
Wye Strawberry/High Tunnel Twilight Meeting – April 13

Weather

2011 Wye Strawberry/High Tunnel Twilight Meeting

Friday, April 1st, 2011

Wednesday, April 13, 2011     6:00 – 8:00 pm
Wye Research & Education Center
211 Farm Lane, Queenstown, MD 21658
(meet at the Farm Operations Complex)

**Rain or Shine**

Hear: University of Maryland and USDA specialists discuss current research and other small fruit growing topics and “programmed production” of small fruit

See: Four small fruit high tunnel trials.

We’ll have refreshments and pre-registration is not necessary. If you need special assistance to attend this program, please call Debby Dant at (410) 827-8056 x115, no later than April 6, 2011.

For additional program information, contact Michael Newell, Horticulture Crops Program Manager, (410) 827-7388 or mnewell@umd.edu

University of Maryland programs are open to all citizens without regard to race, color, gender, disability, religion, age, sexual orientation, marital or parental status or national origin.

News from the Nematode Assay Service

Friday, April 1st, 2011

Bob Mulrooney, Extension Plant Pathologist; bobmul@udel.edu

There is a new sample submission form available on the Plant Clinic website http://ag.udel.edu/plantclinic. This new form is updated to reflect personnel changes and lines for entering email addresses and information that will help us respond as quickly as possible. Please fill out a sample submission form each time you submit samples. These are also available from the county Extension offices when you purchase the soil bags for nematode analysis.

NRCS to Deploy Technical Team to Increase Conservation in Delmarva Area

Friday, April 1st, 2011

DOVER, Del., March 21, 2011- USDA’s Natural Resources Conservation Service (NRCS) recently announced that Delaware will receive $180,000 to help fund a Strategic Watershed Action Team (SWAT) to help growers develop nutrient management plans throughout targeted areas of the Chesapeake Bay Watershed.

NRCS is deploying four SWATs, or technical experts, to provide additional planning, education and technical assistance to farmers to further improve water quality. The four teams will focus on working with producers in the Delmarva area (Delaware and Maryland), Piedmont area (Pennsylvania), Shenandoah Valley (Virginia), and West Virginia.

According to Delaware State Conservationist Russell Morgan, the Delaware portion of the Delmarva SWAT will provide up to two specialists working with farmers to develop and write more than 300 Animal Waste Management Plans or Nutrient Management Plans. “Together with our conservation partners, we can target our resources to significantly reduce nutrient and sediment losses to the Chesapeake Bay.”

Delaware’s conservation partners, the local conservation districts and the State of Delaware, are committing $50,000 in additional funding. Each SWAT will help individual agricultural producers plan and implement conservation practices needed to address priority natural resource concerns.

SWATs will not only help achieve USDA goals, but also support State Watershed Implementation Plan goals for Best Management Practice implementation set through the Environmental Protection Agency (EPA) Total Maximum Daily Load (TMDL) process. It is anticipated that SWAT would further environmental improvement while keeping production agriculture competitive and profitable.

SWAT is just one component of the Presidential Executive Order (EO) Strategy for Protecting and Restoring the Chesapeake Bay Watershed to help USDA implement new conservation practices on four million acres of agricultural working lands in priority watersheds by 2025. Acres treated by SWAT will be tracked to count toward the EO Strategy goal.

SWAT teams are expected to be in place this spring. For more information about SWAT, contact your local USDA Service Center or visit www.nrcs.usda.gov.

New Kent Co. Ag Agent

Friday, April 1st, 2011

Phillip Sylvester, Kent Co., Ag Agent; phillip@udel.edu

Hello, my name is Phillip Sylvester and I have recently joined the University of Delaware Cooperative Extension as the new Agricultural Agent for Kent County. My role as the Kent County Agricultural Agent is to assist and support the county’s agricultural producers and industry through Extension programs in row crop production, pasture and hay production, vegetable production, and environmental issues. Previously, I worked with Monsanto, where I was a research assistant on soybean breeding projects. Prior to that, I worked for Southern States as a field sales associate. My education includes a degree in Plant Protection from the University of Delaware. Currently, I reside outside of Felton and produce grain and vegetable crops on my farm. I am excited to begin this position and look forward to working with Delaware growers. I can be reached at the University of Delaware Paradee Center in Dover at 302-730-4000.

Grain Marketing Highlights – April 1, 2011

Friday, April 1st, 2011

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

Acreage Report
USDA’s prospective corn plantings are modestly above pre-report expectations projected at 92.18 million acres. However, in order for ending stocks to use to gain in 2011-12, corn plantings would need to total 93.4 million acres. Farmers intend to plant 76.61 million acres of soybeans. This is below the average pre-report estimate of 76.9 million and also below last year’s actual planted acres of 77.4 million. At 58.02 million acres, all wheat acres are higher than the expected average of 57.3 million. SRW winter wheat is pegged at 41.2; spring at 14.4 and durum at 2.4. Today’s intentions report can’t account for changes in spring wheat reductions due to flooding, which eventually may lead to a decrease in acres compared with the 13.7 million planted in 2010.

USDA’s prospective plantings report shows farmers intend to plant 245 million acres of the five major crops, up from 236 million last year, and above USDA’s Ag Outlook Forum estimate. Cotton acres, at 12.57 million, are up 15 percent from last year. Average pre-report trade expectations for cotton acreage was at 13.15 million. Prospective Plantings: http://usda.mannlib.cornell.edu/.

Quarterly Stocks
Corn and bean stocks were below expectations; slightly more wheat and sorghum on hand than the trade was looking for. Pre-report estimates for corn stocks on hand at the end of February averaged 6.69 billion bushels, suggesting usage well above the five-year average pace for the second quarter. The actual number came in at 6.52 billion bushels, indicating December-February disappearance of 3.53 billion, up from 3.21 billion during the same period last year. This was stronger use than expected.

Soybean quarterly stocks were expected to come in at 1.299 billion bushels, representing second-quarter usage near the five-year average. Soybean stocks were announced at 1.249 billion bushels, slightly below the average and lowest expectations. This represents a 4% decrease in usage compared with the same period a year ago.

The average pre-report estimate for all wheat ending stocks was 1.399 billion bushels, slightly above the average usage pace. All wheat stocks were pegged at 1.425 billion bushels, slightly above average pre-report expectations. Wheat disappearance is up 20% from last year. Quarterly Grain Stocks: http://usda.mannlib.cornell.edu/.

Prospective Plantings

Acreage (million acres)

3/31/11 Average High Low Actual
2010-2011
USDA Outlook
2010-2011
Corn 92.18 91.84 92.60 91.00 88.19 92.00
Soybeans 76.61 76.87 78.50 75.00 77.40 78.00
All Wheat 58.02 57.29 58.40 56.00 53.60 57.00
Winter 41.23 41.10 42.90 40.20 37.34
Spring 14.43 13.73 14.31 13.00 13.70
Durum 2.37 2.55 2.80 2.40 2.57
Grain Sorghum 5.65 6.65 6.75 6.50 5.40
Cotton 12.57 13.15 13.22 12.97 10.97 13.00

Quarterly Stocks (billion bushels)

3/1/11 Average High Low 12/1/10 3/1/10
Corn 6.523 6.690 6.880 6.552 10.057 7.694
Soybeans 1.249 1.299 1.366 1.266 2.278 1.270
Wheat 1.425 1.399 1.488 1.275 1.933 1.356
Grain Sorghum 0.171 0.167 0.180 0.165 0.238 0.176

Market Strategy

Non-commercial speculators and investment funds can be expected to rebuild long positions based upon the information contained in this report. If demand for U.S. corn increases in 2011-2012, ending stocks could fall to near 500 million bushels. This would equate to an ending stocks-to-use ratio of 3.8% (currently 5%). This takes into account near-ideal planting and growing conditions, resulting in a trend-line yield of 162 bushels/A. Quarterly stocks were lower-than-expected at 6.523 billion bushels. Old-crop export sales were reported at 75.4 million bushels, well above the 21.6 million bushels needed to stay on pace with USDA’s 1.95 billion bushel projection.

Planting intentions for soybeans were reported to be slightly below pre-report expectations. This means that domestic stocks could move below 100 million bushels and stocks-to-use near 3% in the next (2011/2012) marketing year. Quarterly stocks were reported to be less than expected, meaning domestic ending stocks for 2010-2011 could decline in the April supply and demand report. Export sales and shipments were bullish as old-crop sales of 5.3 million bushels and shipments of 30.4 million bushels were above the amounts needed to stay on pace with USDA’s 1.59 billion bushel projection.

The Prospective Plantings and Quarterly Stocks reports were considered bearish for wheat. Spillover support tied to the rally in row-crops should provide support. Old-crop export sales of 10 million bushels were disappointing but above the 5.8 million bushels needed to stay on pace with USDA’s 1.275 billion bushel projection. However, shipments of 32.6 million bushels fell short, meaning all wheat shipments will need to average 43 million bushels the last nine weeks of the marketing year.

Currently, Dec ‘11 corn futures are trading at $6.25 (limit-up); Nov ‘11 soybeans at $14.06 (up 42 cents); and July ‘11 SRW wheat is trading at $7.84 (up 20 cents per bushel).

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

Viruses in Winter Wheat

Friday, April 1st, 2011

Bob Mulrooney, Extension Plant Pathologist; bobmul@udel.edu

The first winter wheat sample with virus symptoms arrived last week. It was sent for confirmation and was determined to be wheat soilborne mosaic virus. Wheat on the Delmarva can be infected by four possible virus diseases. The aphid-transmitted barley yellow dwarf mosaic virus is probably the most common, depending on how high aphid populations are in the fall and early spring. Often irregular patches of stunted wheat occur in wheat fields and as the season warms up infected young leaves will become yellow, and then turn red. Wheat spindle streak mosaic causes a yellow discoloration to wheat seedlings. This yellow discoloration is often most intense in low areas of the field. Leaves of infected plants have long, yellow streaks that are slightly wider in the middle than at their ends. Symptoms are similar to wheat soilborne mosaic and plants often are infected with both diseases. Winter wheat infected by wheat soilborne mosaic develops a pale-yellow discoloration shortly after breaking dormancy in the spring. The incidence of wheat soilborne mosaic is often greater in low areas of the field where moist soil conditions favor growth of the protozoa that spread this viral disease. Leaves of infected plants often have a mosaic pattern of dark green blotches on a pale greenish-yellow background. Symptoms will normally fade when warm temperatures slow the activity of the virus within infected plants. Control of both these soilborne diseases is by planting resistant varieties.

The least common virus disease of wheat that we see is wheat streak mosaic. Leaves of plants infected with wheat streak mosaic have bright yellow streaking. Symptoms are often most severe near the tip of the leaf. The virus that causes wheat streak mosaic survives in volunteer wheat and spreads by wheat curl mites. The disease is often most severe in areas of a field that are closest to these sources of the disease and mites.

Barley yellow dwarf mosaic virus

Wheat spindle streak mosaic virus

Wheat soilborne mosaic virus

Wheat streak mosaic virus
(Last three photos from Wheat Disease Identification published by NCERA-184, which will be available soon.)

It can be very difficult to positively identify these virus diseases especially early in the spring. They can look like other diseases or nutritional disorders. Testing of infected plants can help diagnose the problem to avoid repeating it in the future or eliminate other possible causes of the symptoms. Unfortunately by the time you see symptoms of these virus diseases there is no control of any of these diseases.

Agronomic Crop Insects – April 1, 2011

Friday, April 1st, 2011

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

Alfalfa
Alfalfa Weevil:
We are starting to see the first hatch of alfalfa weevil eggs. As soon as the weather begins to warm up, you should begin to sample for larvae on a weekly basis. Look for small larvae feeding in the tips of plants producing a round, pinhole type of feeding. Once you detect tip feeding, a full field sample should be taken. The most accurate way to time an application is to sample stems and determine the number of weevils per stem. A minimum of 30 stems should be collected per field and placed top first in a bucket to dislodge larvae from the tips. Then count the number of weevils per stem. The following thresholds, based on the height of the alfalfa, should be used as a guideline when making a treatment decision: up to 11 inches tall – 0.7 per stem; 12 inches tall – 1.0 per stem; 13 – 15 inches tall – 1.5 per stem; 16 inches tall – 2.0 per stem; and 17 – 18 inches tall – 2.5 per stem. Numerous pyrethroids are now labeled for alfalfa weevil including Baythroid XL, Mustang MAX, Proaxis, Warrior II and numerous generic pyrethroids. Imidan, Lorsban, Lannate and Steward are also labeled for alfalfa weevil control. Be sure to check all labels for rates, restrictions and days to harvest before application. The following is a link to our recently updated fact sheet including pictures of life stages and damage.  http://ag.udel.edu/extension/IPM/ExtensionFactSheets/AlphalfaWeevilIPM-1.pdf.

Timothy
Cereal Rust Mites:
Since spring green-up is underway, be sure to sample fields for cereal rust mite activity. Mites can be found in fields at this time. These mites are very small, so the use of a 20x-magnifying lens may be helpful. If rust mites become a problem, Sevin XLR Plus is still the only labeled, effective material: http://www.cdms.net/LDat/ld332013.pdf . Be sure to read the label for information on the number of applications per season as well as the days to harvest. For effective rust mite control, the use of the higher labeled rate and at least 25 gal/A of carrier to get good coverage of leaf surfaces generally results in better control. The following is a link to new fact sheet including pictures of mites and damage: http://ag.udel.edu/extension/IPM/ExtensionFactSheets/CerealRustMiteIPM-9.pdf.

Wheat
Cereal Leaf Beetle:
It is time to begin sampling fields for cereal leaf beetle activity. We are starting to find evidence of adult feeding, so fields should now be scouted for egg masses. The threshold for cereal leaf beetle includes sampling for eggs, especially in high management wheat fields or in fields with historical problems. The eggs are elliptical, about 1/32 inch long, yellow in color when first laid, changing to a burnt orange prior to hatching. The following is a link to our recently updated fact sheet including pictures of life stages and damage: http://ag.udel.edu/extension/IPM/ExtensionFactSheets/CerealLeafBeetleFactSheetIPM-5.pdf.

Generally, eggs are laid singly or in small scattered groups (end-to-end) on the upper leaf surface and parallel to the leaf veins. Cereal leaf beetle larvae are brown to black, range in size from 1/32 to ¼ inch long, and eat streaks of tissue from the upper leaf surface. Since cereal leaf beetle populations are often unevenly distributed within the field, it is important to carefully sample fields so that you do not over or under estimate a potential problem. Eggs and small larvae should be sampled by examining 10 tillers from 10 evenly spaced locations in the field while avoiding field edges. This will result in 100 tillers (stems) per field being examined. Eggs and larvae may be found on leaves near the ground so careful examination is critical. You should also check stems at random while walking through a major portion of the field and sampling 100 stems. The treatment threshold is 25 or more eggs and/or small larvae per 100 tillers. If you are using this threshold, it is important that you wait until at least 50% are in the larval stage (i.e. after 50% egg hatch).

Winter Grain Mites: With the recent cooler weather, consultants are starting to report an increase in winter grain mite populations, especially in no-till wheat planted into corn stubble. Temperature and moisture are the most important factors influencing mite development and abundance. Cool, rather than warm, temperatures favor their development. Egg laying is heaviest between 50° and 60°F and the optimum conditions for hatching are between 44° and 55°F. Mite activity in the spring drops rapidly and the eggs fail to hatch when the daily temperature exceeds 75°F. The larvae as well as the adults feed higher up on the plants at night or on cloudy days. Heavily infested fields appear grayish or silvery, a result of the removal of plant chlorophyll by mite feeding. When high infestations feed on the plants for several days, the tips of the leaves exhibit a scorched appearance and then turn brown, and the entire plant may die. These mites do not cause the yellowing characteristic of spider mite feeding. Many of the infested plants do not die, but become stunted and produce little forage or grain; damage on young plants, however, is more severe than on large, healthy ones. Damage may also be greater in plants stressed by nutrient deficiencies or drought conditions. There are two types of damage to the small grain: (a) reduced amount of forage throughout the winter and (b) reduced yields of grain in the spring and summer. The following is a link to our recently updated fact sheet including pictures of mites: http://ag.udel.edu/extension/IPM/ExtensionFactSheets/WinterGrainMitesIPM-8.pdf.

The most effective scouting method is to use a 10x hand lens, checking both plant foliage and crop residue on the soil surface for the presence of immature and adult mites. A sweep net may also be effective in determining if mites are present. The best time to scout is early in the morning and at dusk on calm days because the mites will seek refuge during the day in the top 4 or 5 inches of the soil profile to avoid the sunlight. On cool, overcast days, they may be observed actively feeding on plant foliage throughout the day.

No economic thresholds have been developed for WGM in small grain fields. However, as a general rule of thumb, if plants exhibit symptoms of damage, weather conditions are favorable and several mites per plant are found, a chemical control may be necessary to prevent or reduce yield loss. If populations are small and the plants show no feeding injury or if populations and damage symptoms are isolated, the field should be scouted more frequently to insure yield losses are kept at a minimum.

Mites and Aphids in Strawberry Plantings

Friday, April 1st, 2011

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

Over the last few weeks I have visited several strawberry fields, with most being in high tunnels, and have noticed infestations of aphids and especially mites. The mites were found in most of the strawberry patches I looked at, while aphids were in about a quarter of them. There were two species of mites found: the twospotted spider mite, Tetranychus urticae, and the strawberry spider mite, (sometimes called the strawberry red spider mite) T. atlanticus. Strawberry spider mite adults are generally red, but overwintering twospotted spider mites are also a red-orange and therefore most of the mites that can be seen with a naked eye will be reddish in color. Spider mites overwinter as adults in the soil or leaf litter, although they may remain somewhat active on strawberry plants in high tunnels through the winter. I found in quite a few high tunnel strawberries, but not on outdoor strawberries, mite eggs. The light yellowish eggs are pearl-like in appearance and are attached to the undersides of leaves or on stems (Fig. 1). Aphid species found were the melon aphid, Aphis gossypii and the green peach aphid, Myzus persicae. Aphids are still in low numbers outdoors, but in some places in the high tunnels aphids have started multiplying rapidly when we had those few days of warm weather. These overwintering populations of aphids and mites can be difficult to control as they are “entrenched” in the strawberries. Growers should check their strawberries for both mites and aphids now, especially if you have them in a high tunnel or under a row cover.

The most difficult thing to accomplish for good control is getting adequate spray coverage. Many of the spray applications do a good job of covering the top of the leaves, but do a poor job of reaching the underside of the trifoliates. The underside area of the leaf that usually sees very little chemical deposition is in the ‘palm’ of the leaf (Fig 2). These are the areas where mites and aphids can still be found even after a few sprays and need to be carefully checked a few days after an application. Good coverage is essential. One grower used a leaf blower-like back pack sprayer and applied 9 gallons of spray onto three rows of strawberries in a 14 x 100 ft area. Two applications of 1% (by volume) horticultural oil were applied about 7-8 days apart. He got excellent spray coverage on the underside of the leaves and consequently excellent control of the mites and the few aphids that were present using the horticultural oil. Control of the adults and nymphs was around 98%. By using two applications about one week apart it is possible to control both the adults and nymphs, but also the newly hatched eggs. Oil is a good management tactic to use at this time of year as the plants are small and any possible burn from using the oil is a very low risk. An added benefit of the oil is that it is rather inexpensive. I would like to see growers use something like oil now and save the other chemicals for later in the season when plants are much bigger and there is a flare up of mites or aphids. Using oils now also will greatly reduce any development of mite resistance to chemicals over the course of the season. Acramite and Agri-Mek are two excellent miticides, but Acramite should only be used once during a season and resistance is possible with either if multiple applications are made and there is poor coverage. Thionex or Provado (or other neonicotinoids) can be used for aphid control.

Protecting Your Plasticulture Strawberry Investment

Friday, April 1st, 2011

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

Prior to the cold snap, flowering had begun in some plasticulture strawberry fields in the region. As cold weather returned last week, temperatures dropped into the mid to low 20s requiring that row covers go back on. As a reminder, as buds become active but before flowers open, strawberry buds can survive down to temperatures of 22-27ºF, depending on just how close they are to opening. As flowers open, strawberries can only tolerate drops in temperature down to 30ºF. Small green fruit can stand temperatures down to 28ºF. During flowering and fruiting be prepared to freeze protect using row covers and in very cold conditions, sprinklers. It is critical to monitor temperatures. Temperature recorders that can be placed at crown height under the row cover are wise investments to do this monitoring.

When using sprinklers for frost protection, they must be used correctly. The idea is to slowly build up ice over the period when temperatures are below freezing over the plant or row covers. As ice is formed, some heat is released to the plant surface and to the surrounding air, due to the heat of fusion. To do this, sprinklers must be turned on before temperatures are at 34-35ºF. Use low volume sprinklers and apply irrigation throughout the night, building ice all night. Continue into the morning until ice has melted. An application rate of 0.15 inch per hour with no wind will provide protection to 22ºF. At colder temperatures or higher wind speeds more water will be needed.

It is recommended that for protection against frost above freezing, use sprinklers or row covers alone, for freezing temperatures in the mid to high 20s use sprinklers or row covers alone, for temperatures in the low 20s or below, use both sprinklers and row covers. A combination of row covers and sprinklers has been shown to protect below 20ºF.

Growers are strongly advised to subscribe to a weather forecast service to alert them of potential freezes in order to make frost protection decisions.

As fields are uncovered again, finish any cleanup of dead plant material and apply additional disease, mite, and insect controls. Fertigate nitrogen through the drip system, if it has not already been applied and monitor N levels using petiole and leaf samples. Petiole nitrate-nitrogen levels can be a good way to monitor and adjust your N program. At green-up, petiole nitrate-N should be around 1000-1500 ppm. As growth takes off, petiole nitrate-N should rise to above 4000 ppm. Petiole nitrate-N should be at 3000 – 4000 ppm during the first 4 weeks of picking and then decline gradually to around 1000 ppm at the end of harvest.

For more information about monitoring plasticulture strawberry nutrition, go the North Carolina Department of Agriculture & Consumer Services Agronomic Division plant tissue analysis site http://www.ncagr.gov/agronomi/pdffiles/sberrypta.pdf.