Posts Tagged ‘20:20’

WCU Volume 20, Issue 20 – August 3, 2012

Thursday, August 2nd, 2012

PDF Version of WCU 20:20 – August 3, 2012

Vegetable Crops
Vegetable Crop Insects

Agronomic Crops
Agronomic Crop Insects
Review of Barley Yellow Dwarf in 2012
Aphids Prevention and Barley Yellow Dwarf Management
Grain Marketing Highlights

Cleaning Equipment to Prevent Spreading Weed Problems Around

2012 Mid-Atlantic Precision Ag Equipment Day – August 8
2012 Summer Turf & Nursery Expo – August 16
Extension Vegetable & Fruit Program Open House – August 21
UD Field Day for Sustainable and Organic Agriculture – September 13


UD Extension Tour and Discussion Improving Soil Health / Cover Crops for Agronomic and Commercial Vegetables

Thursday, August 2nd, 2012

Thursday, September 13, 2012   4:00 – 8:00 p.m.
Carvel Research and Education Center
16483 County Seat Hwy
Georgetown, DE 19947

Come see and hear about many of the UD Extension’s field research projects for Agronomic and Commercial vegetables which involve soil health or cover crop components.

A variety of projects will be presented including:

● Reduced tillage/no-till for limas

● Evaluation of biofumigant and winter kill cover crops

● Pumpkins produced with rye cover crop – influence of rye on weed control and fruit quality

● Use of cover crop and reduced tillage in a rotational system for commercial vegetable production – strategies for fitting cover crops into different systems

● Soybean production with rye cover crops – advantages and challenges

● Also discussion of on-going projects with bee pollination and irrigation

Dinner will be served.  There is no charge for this field day.

After dinner we will have a conversation on our current and future research efforts and would like feedback on future educational programs

Please pre-register by contacting Karen Adams at 302-856-2585 ext. 540 or  Register by September 11.

CCA: S/W 1; NM 0.5; CM 0.5; IPM 0.5
DE Nutrient Management: 1.0
DE Pesticide Credits: 1 PA; 1 Agric. Plant; 1 Demo/Research

2012 Mid-Atlantic Precision Ag Equipment Day

Thursday, August 2nd, 2012

Wednesday, August 8     9:00 a.m – 3:15 p.m.
Caroline County 4-H Park
8230 Detour Road, Denton, MD  21629

Practical and informative advice will be given on precision seeding, economics and practical implementation of planter section control, modifying equipment for variable rate application, variable rate irrigation, and much more. Come learn from some of the top, nationally recognized speakers in agriculture equipment and machinery engineering.

Precision Seeding Systems
Dr. Randy Taylor, Oklahoma State University

Variable Rate Fertilizer Application Equipment
Dr. Joe Luck, University of Nebraska-Lincoln

Increasing Farm Profits using Planter Automatic Section Control
Dr. Mike Buschermohle and Lori Gibson, University of Tennessee

Variable Rate Irrigation
Wesley Porter, Oklahoma State University

Additional schedule and registration information is online at

Cleaning Equipment to Prevent Spreading Weed Problems Around

Thursday, August 2nd, 2012

Mark VanGessel, Extension Weed Specialist;

This summer has been very challenging for weed control so I want to remind you to not spread the problems around the farm or from farm to farm. I believe that a lot of our new weed infestations are due to transporting seed on equipment, whether the equipment is mowers, combines, or vegetable harvesters. I have seen a number of fields with heavy weed pressure due to escapes. Some of these are suspected to be resistant biotypes, others just hard to control weeds. If a particular weed is giving you headaches, wouldn’t you rather deal with it in only one field rather than all of your fields? Ask yourself, what you would do if you could no longer use the best herbicide for a problem weed. In vegetables, where we only have one or two broadleaf herbicides, what are your options when they are no longer effective?

Granted weeds that get blown around (like marestail or thistle) or spread (by birds like pokeweed) are difficult to prevent. Nevertheless, many of our problems are due to moving seeds from field to field on equipment; pigweed and lambsquarters are two that come to mind. Take the time to clean the equipment in the field before it gets moved and isolate where those infestations are located. This is true for all fields. A new weed or a resistant biotype does not just take over a field in one year. A few plants get started and they produce seeds which next year leads to more plants and more seeds (see where this is going?). Prevent the problems from developing and spreading. Clean the equipment thoroughly, before it leaves the field, and leave the weed seed where you found it.

Grain Marketing Highlights – August 3, 2012

Thursday, August 2nd, 2012

Carl German, Extension Crops Marketing Specialist;

Crop Size Projections Expected to Decline
With 48% of the nation’s corn and 37% of the soybean crop rated poor to very poor, 2012 crop production forecasts will be dropping in next week’s release of the August 10 monthly supply and demand report. Just how much drop in the crop production forecast that will occur is anybody’s guess at this point in time. So far preliminary estimates for U.S. corn production range from 120 to 130 (+ or –) bushels per acre for corn with the lowest estimate for soybeans around 34 (+ or –) bushels per acre. The August report will project a short crop for both U.S. corn and soybean production, meaning projected use will exceed production and stocks will be drawn down.

Market Strategy
Most of the focus recently has been on the short crop (supply side of the equation) that the U.S. is expected to harvest, which happens to be getting underway as of this writing. That would preclude an expectation of even higher prices yet to come. However, it is important to bear in mind the demand side of the equation too. Reducing crop size is dictating the necessity to make even larger cuts in domestic demand, i.e., exports, feed use, ethanol production, etc. That realization appears to be causing the non-commercials to be taking a breather. Speculators are said to be protecting profits and losing their appetite for the extreme volatility these markets are currently experiencing. In today’s trade the nearby and new crop corn, soybean, and wheat futures prices posted double digit declines across the board.

Sharp demand reductions are now occurring, with some of those cuts perceived to be demand destruction. It will take a long time to get some of the lost demand back. Beef, dairy, and hog producers are cutting production due to the drought and high feed costs. Much of that demand will take some time to regain because of the production cycle to bring a heifer into milk production or a steer to market. U.S. export demand is being reduced while imports are picking up. The problem is, imported corn from South America or anywhere else in the world will barely make a dent in U.S. needs.

After reaching a record high of $8.20 per bushel earlier this week, new crop Dec ‘12 corn futures were posted at $7.91 per bushel near the close of day trade; Nov ‘12 soybeans at $16.12; and Dec ‘12 SRW wheat at $8.81 per bushel (August 1, 1:47 p.m. CDT). New crop Nov ‘12 soybean futures recorded a high of $16.91 on July 23rd with the high for Dec ‘12 SRW recorded at $9.48 per bushel on July 20th. July ‘13 SRW wheat futures are currently posting at $8.30 per bushel after reaching a recent high of $8.44 on July 5.

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

Aphids Prevention and Barley Yellow Dwarf Management

Thursday, August 2nd, 2012

Joanne Whalen, Extension IPM Specialist;, Phillip Sylvester, Kent Co., Ag Agent; and Nancy Gregory, Plant Diagnostician;

As discussed in the article, Review of Barley Yellow Dwarf in 2012, the spread of barley yellow dwarf virus (BYDV) is completely dependent on aphids transmitting the virus which causes the infection. There are four aphid species occurring in Delaware that are capable of transmitting BYDV from infected grasses into wheat including the English grain aphid, bird cherry-oat aphid, corn leaf aphid, and the greenbug. For photos to help you identify aphids go to:

Aphids can infest small grain fields in the fall and again in the spring. The number of aphids arriving in fields in the fall is often dependent on the growing conditions the preceding summer. In general, cooler summer conditions with adequate rainfall followed by a warm, dry fall favors aphid development, especially in early planted fields. In drier summers, fewer aphids are produced due to reduced host plant quality. It should be noted that greenbug aphids (which cause direct damage to small grains as well as transmit BYDV) are favored by cool, late summer conditions. Aphid population densities in the fall are also affected by when the first hard frost occurs in relation to wheat seedling emergence. Crops that emerge long before a hard freeze have a greater potential for aphid infestation (and exposure to BYDV). Planting after the fly free date can help to help to manage aphids as long as the freeze occurs when expected. Aphids arriving in the fall will continue to feed and reproduce as long as temperatures remain above 48°F.

In areas where you have seen BYDV in the past, where you are planting early (before the Hessian fly-free date), or you have seen direct damage by greenbug aphids, a commercial applied seed treatment which includes an insecticide would be a good control option for fall infestations. Another option would be to scout fields and apply a foliar insecticide. Information from Kentucky indicates that planting date is the most important factor determining the intensity of an aphid infestation. The most important time for controlling aphids in the fall is the first 30 days following emergence. The second most important time is the second 30 days following emergence. So it will be important to scout wheat starting at plant emergence if you plan to use a foliar insecticide for fall aphid management. The following link to a fact sheet from Kentucky provides more information on aphids and BYDV in wheat (

Since the incidence of BYDV has not been widespread in past years in Delaware and Maryland, we do not have current data from our area evaluating thresholds to time sprays for fall aphid management. The following thresholds from Kentucky (included in the above fact sheet) could be considered when making a decision to apply a fall foliar insecticide : (a) the first 30 days after planting treat if you find an average of three or more aphids per row-foot, (b) from 30-60 days after planting treat if you find six or more aphids per row-foot, and (c) more than 60 days after the plants emerge treat if you find ten or more aphids per row-foot. Depending on weather conditions, a second application could be needed, especially if temperatures remain warm. As we saw this past season, aphid populations remained high throughout the winter and early spring so you will need to continue scouting if conditions remain mild again. They also indicate that in some years these thresholds may be too high and in others too low but currently this is the best available information. In addition, the risk of BYD infection varies from year to year. At this point, we are still not certain if the 2012 season was just an unusual one for BYD or if we will continue to see an increase in problems. We hope to survey for aphids this fall and evaluate these thresholds under our conditions.

Review of Barley Yellow Dwarf in 2012

Thursday, August 2nd, 2012

Phillip Sylvester, Kent Co., Ag Agent;, Joanne Whalen, Extension IPM Specialist; and Nancy Gregory, Plant Diagnostician;

As we approach the upcoming small grains planting season, it is a good time to discuss barley yellow dwarf management. Barley yellow dwarf (BYD) can be found most years in a few wheat fields in Delaware. It is not uncommon to see a few infected plants, primarily in the spring. In 2012, the number of fields with infected plants appeared to be generally higher compared to most seasons. Impact on yield was variable, though it was estimated that some fields experienced a 5% yield loss. The dry spring weather in Delaware had a larger impact on yield, therefore it was difficult to estimate the true impact of BYD. It is important to understand the causal agents, symptoms, and disease cycle in order to best manage BYD. Barley yellow dwarf is the most widespread virus disease of cereal crops worldwide and can infect other crops such as rye, barley, oats, and corn, though the greatest concern in our area is in wheat.

Causal Agents
There are numerous virus types that actually cause BYD. While the taxonomy of BYD can be complicated, it’s important to note that some strains are more severe than others. The ones that are of greatest concern in our area are (in order from least severe to most severe): BYDV-MAV, BYDV-PAV (severe strain), and CYDV-RPV. CYDV-RPV, cereal yellow dwarf, was named and then later found to be a related strain of BYD. Both CYDV-RPV and BYDV-PAV were confirmed in the samples submitted this past spring from wheat fields in Delaware.

The BYD viruses are limited to the phloem and can only be transmitted from plant to plant by aphids which have piercing/sucking mouthparts. The infection occurs after aphids feed on infected hosts, such as wild grasses, and then move into and feed on wheat fields. The wild grasses may be infected yet show no symptoms. It can take as little as 12-48 hours from the time aphids feed on the infected grasses until infection has occurred in wheat plants. This can occur anytime that aphids are actively feeding, which would typically be in the fall and spring months when the weather is warmer. Since the spread of barley yellow dwarf depends on aphids, management of the aphids may be helpful in fields with known problems of barley yellow dwarf in the past. Remember that the viruses causing BYD are only transmitted by aphids and are not known to be seed-borne. Read the Aphids Prevention and Barley Yellow Dwarf Management article in this issue of WCU for more on management.

Symptoms include leaf discoloration (Figures 1- 3), shortening of the internodes, and general stunting of the plant. Leaf discoloration typically has a characteristic purple to yellow color. Symptoms become exacerbated by cool weather and high light intensity. Hot spots (cluster of infected plants) may occur near field borders, field corners, or near woods depending on how the aphids moved. To further complicate matters, the plant’s reaction to the infection may vary depending on when the plant was infected and the variety of wheat. Fall infections usually result in more stunting and less tillering while spring infections tend to discolor the flag leaf and are thought to cause little yield loss. Other viruses such as wheat spindle streak and/or wheat soil-borne mosaic virus may infect the plant causing additional symptoms (see Figure 4). The other viruses are not transmitted by aphids. To learn more about the other viruses we encounter in Delaware, read Bob Mulrooney’s article on Viruses in Winter Wheat at:  It’s difficult to identify viruses in the field and samples should be submitted to a lab for testing to confirm virus infection.

Figure 1. Wheat plant infected with barley yellow dwarf (BYDV-PAV).

Figure 2. Wheat plants infected with barley yellow dwarf (BYDV-PAV).

 Figure 3. Wheat plants infected with barley yellow dwarf (BYDV-PAV).

 Figure 4. Wheat Plant infected with BYDV-PAV, CYDV-RPV, wheat spindle streak mosaic virus, and wheat soil-borne mosaic virus.

Figure 5. Close up of wheat infected with BYDV-PAV, CYDV-RPV, and wheat spindle streak mosaic virus.

Agronomic Crop Insects – August 3, 2012

Thursday, August 2nd, 2012

Joanne Whalen, Extension IPM Specialist;

Alfalfa and Grass Hay Crops
We are starting to hear reports of the first occurrence of defoliators in hay crops. Fall armyworm can cause significant damage in grass hay so be sure to watch carefully since early detection is important to achieve effective control with labeled products. In alfalfa, a number of defoliators can cause problems including corn earworm, fall armyworm, beet armyworm and webworms. No thresholds are available; however, controls should be applied before significant defoliation occurs.

We continue to find fields with economic levels of spider mites. In areas that have received rain, it generally has helped beans to grow; however, if economic populations were present before the rain they can still be found. As a reminder, under heavy mite pressure and extended hot, dry weather, it often takes an extended period of free moisture on leaves, high humidity during the day and cool evening temperatures to get an increase in the fungal pathogens that can significantly reduce exploded mite populations. In many years, populations can start to decline by mid-August and we have started to find a few diseased mites. However, we are not seeing a significant decline in populations so it is important to continue to scout and apply controls if economic populations are present.

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).

Corn earworm moth trap catches continue to increase and larvae can be found in fields in Kent and Sussex counties. Be sure to scout both full season and double crop soybeans for this insect pest. Only time will tell if we will have a corn earworm outbreak in soybeans in our area. As we have seen in past years, trap catches can give an indication of the potential for a problem; however, only scouting on a routine basis will tell you if you have an economic problem. In the past, we have used the treatment threshold of 3 corn earworms per 25 sweeps in narrow fields and 5 corn earworms per 25 sweeps in wide row fields (20 inches or greater). These are static thresholds that were calculated for a 10-year average soybean bushel value of $6.28. A better approach to determining a threshold is to access the Corn Earworm Calculator ( which estimates a threshold based on the actual treatment cost and bushel value you enter.

Consultants have also found a significant increase in beet armyworm (BAW) populations and defoliation. Since this insect is primarily a defoliator, you should use the defoliation thresholds to make a treatment decision. As a reminder, the pyrethroids will not provide effective control so a beet armyworm product labeled for soybeans will need to be applied.

Vegetable Crop Insects – August 3, 2012

Thursday, August 2nd, 2012

Joanne Whalen, Extension IPM Specialist;

As soon as plants are set in the field, be sure to sample for cabbage looper and diamondback larvae. A treatment will be needed before larvae move into the hearts of the plants. In recent years, we have seen more Harlequin bug activity in cabbage. In general, most of the “worm” materials are not effective on Harlequin bugs. The pyrethroids have provided control in years past.

Lima Beans
Continue to scout for spider mites, stink bugs, lygus bugs and corn earworm. As soon as pin pods are present, be sure to watch carefully for plant bug and stinkbug adults and nymphs as well as corn earworm larvae. As a general guideline, treatment should be considered for plant bugs and stink bugs if you find 15 adults and/or nymphs per 50 sweeps. A treatment will be needed for corn earworm if you find one corn earworm larvae per 6 ft-of-row.

Continue to scout all melons for aphids, cucumber beetles, and spider mites. We are starting to see an increase in aphid populations. Treatments should be applied before populations explode and leaf curling occurs.

In areas where corn borers are being caught in local traps, fields should be sprayed on a 7-day schedule for corn borer control. If corn borer trap catches increase to above 10 per night, a 5 to 7-day schedule may be needed. Since trap catches can increase quickly at this time of year, be sure to check local moth catches in your area by calling the Crop Pest Hotline (in state: 800-345-7544; out of state: 302-831-8851) or visiting our website at ( We continue to find beet armyworms (BAW) so be sure to watch for feeding signs and apply treatments before significant webbing occurs. We can also find aphids in fields and spider mites in fields and populations of both can explode quickly. As a general guideline, treatment may be needed if you find one or more aphids per leaf and beneficial activity is low.

Snap Beans
At this time of year, you will need to consider a treatment for both corn borer and corn earworms. Sprays are needed at the bud and pin stages on processing beans for corn borer control. An earworm spray will also be needed at the pin stage as populations have started to increase. As a reminder, Orthene (acephate) will not provide effective corn earworm control in processing snap beans. If Orthene is used for corn borer control you will need to combine it with a corn earworm material. You will need to check our website for the most recent trap catches to help decide on the spray interval between the pin stage and harvest for processing snap beans ( and Once pins are present on fresh market snap beans, a 7 day schedule should be maintained for corn borer and corn earworm control.

Sweet Corn
The first “silk sprays” will be needed as soon as ear shanks are visible. Be sure to check both blacklight and pheromone trap catches for silk spray schedules since the spray schedules can quickly change. Trap catches are generally updated on Tuesday and Friday mornings ( and You can also call the Crop Pest Hotline (in state: 800-345-7544; out of state: 302-831-8851). Fall armyworm populations are staring to increase in late planted corn. A whorl stage treatment should be considered for fall armyworm when 12-15% of the plants are infested. Since fall armyworm feed deep in the whorls, sprays should be directed into the whorls and multiple applications are often needed to achieve control. Be sure to check all labels for days to harvest and maximum amount allowed per acre.

Extension Vegetable & Fruit Program Open House

Friday, July 27th, 2012

Tuesday, August 21     4:00 – 8:00 p.m.
Carvel Research and Education Center
16483 County Seat Hwy
Georgetown, DE 19947

Come see and hear about many of the UD Extension Vegetable and Fruit Program’s field research projects from the 2012 season.

Watermelons: pollination, potassium fertilization, stress mitigation, variety trial and more…

Onions: overwintering and spring transplanted onion production

Lima Beans: tillage practices, re-growth production, breeding for stress tolerance and disease resistance

Fruit: fall strawberry and blackberry production

Lettuce: spring variety trial results and tour of fall varieties

Sweet Corn: fresh market variety trial results, processing corn population and tillage practice studies

Dinner featuring local produce will be served.

Please pre-register by contacting Karen Adams at 302-856-2585 ext. 540 or