Posts Tagged ‘18:22’

Cucurbit Downy Mildew Update

Friday, August 13th, 2010

Bob Mulrooney, Extension Plant Pathologist;

Downy mildew on cucumbers is increasing in occurrence in commercial acreage but appears to not be reducing yields at the present time. Maintain sprays schedules on an appropriate interval. As we get later in the season it often means starting a spray program at the 1 to 3 leaf stage and keeping on a 7-day program initially. The forecast for July 29 was high risk for Delmarva, and depending where you were thundershowers would have brought rain and possibly spores as well. Keep cucumbers protected. New Jersey reported its first downy mildew occurrence on Thursday, July 29.

WCU Volume 18, Issue 22 – August 13, 2010

Friday, August 13th, 2010

PDF Version of WCU 18:22 – August 13, 2010

In this issue:

Vegetable Crop Insects
Preserving the Late Set on Watermelons
Watermelon Fruit Blotch
Some Ugly Tomato Fields

Agronomic Crops
Agronomic Crop Insects
Grain Marketing Highlights

Sustainable Vegetable Production Demonstration – August 17
Equine Pasture Walk – August 24
Twilight Tour with Bees – August 30
Pole Lima Bean Open House – September 21


Pole Lima Bean Open House

Friday, August 13th, 2010

Tuesday, September 21, 2010    11 a.m. – 2 p.m.
Delaware State University
Outreach and Research Center
Smyrna, DE

● Pole lima bean trial based on planting date on half acre plot

● Ethnic crop plots

●  High tunnel season extension

● Organic vegetable production

Lunch will be provided.

RSVP by September 14:
Phone: 302-857-6425
Fax: 302-857-6430
E-mail : 
If you have any questions or any special needs, please contact us today.

Grain Marketing Highlights

Friday, August 13th, 2010

Carl German, Extension Crops Marketing Specialist;

USDA Cuts Corn Ending Stocks
U.S. farmers are on track to produce record-high corn and soybean crops this fall, USDA forecast in its August crop production report released early Thursday, with 13.365 billion bushels of corn and 3.433 billion bushels of soybeans. Average corn yield is forecast at a record-high 165 bushels per acre, and soybean yield is forecast at 44 bushels per acre, same as last year. Increases in production are offset by increases in demand, leaving ending stocks for corn down from last month and soybean ending stocks unchanged.

On the production side, the numbers should be considered bearish for soybeans and corn, as both came in above the average estimates and are record large. Wheat should be considered neutral as USDA’s estimate was slightly below the average pre-report estimate.

The market should find support as demand continues to improve, most notably in wheat, where exports were increased 200 million bushels in response to the Russian drought.

Traders may be looking closely at world wheat supply and demand numbers, following the recent volatility in the wheat markets. USDA cut both world production and ending stocks for 2010/11, and lowered its estimate for Russian wheat production to 45 million metric tons, from 53 MMT in July. Those numbers are within the range of trade expectations.

U.S. CROP PRODUCTION (Million Bushels) 2010-2011

  Aug Avg High Low July 2009-10 
Corn 13,365 13,280 13,524 13,120 13,245 13,110
Soybeans 3,433 3,360 3,432 3,290 3,345 3,359
Grain Sorghum 383 351 357 346 350 383
All Wheat 2,265 2,230 2,250 2,172 2,216 2,216
All Winter 1,523 1,504 1,516 1,466 1,505 1,523
Spring 633 614 632 599 607 584
Durum 109 105 109 101 104 109

U.S. AVERAGE YIELD (Bushels per Acre) 2010-2011

  Aug Avg High Low July 2009-10
Corn 165.0 164.1 167.4 162.0 163.5 164.7
Soybeans 44.0 43.2 44.0 42.0 42.9 44.0
Grain Sorghum 74.1 67.9 68.2 67.5 67.6 69.4

U.S. ENDING STOCKS (Million Bushels) 2010-2011

  Aug Avg High Low July
Corn 1,312 1,306 1,535 1,075 1,373
Soybeans 360 350 378 275 360
Grain Sorghum 41 32 36 29 33
Wheat 952 962 1,132 699 1,093

U.S. ENDING STOCKS (Million Bushels) 2009-2010

  Aug Avg High Low July 2008-09
Corn 1,426 1,470 1,523 1,425 1,478 1,673
Soybeans 160 169 181 153 175 138
Grain Sorghum 28 51 55 46 28 55

WORLD ENDING STOCKS (Million Metric Tons)

  2010-2011 2009-2010
  Aug July Aug July
Wheat 174.76 187.05 193.97 193.02
Corn 139.20 141.08 139.03 139.59
Soybeans 64.73 67.76 63.52 65.35

WORLD PRODUCTION (Million Metric Tons)

  2010-2011 2009-2010
  Aug July Aug July
Brazil soybeans 65.0 65.0 69.0 69.0
Argentine soybeans 50.0 50.0 54.5 54.5
Argentine corn 21.0 21.0 22.5 22.5
Brazil corn 51.0 51.0 54.35 53.0
Canada wheat 20.5 20.5 26.5 26.5
Russia wheat 45.0 53.0 61.7 61.7

Source: DTN

Market Strategy
Overall, this report should be considered price positive. In the near term, commodity markets are more likely to react to the effects of outside market forces. Overnight, those forces were mixed with the dollar higher and energy lower. The Dow, as of this writing, is considerably lower on the week. General economic conditions in the U.S. and world remain weak.

Commodity prices bid higher in overnight trade, possibly anticipating larger declines in ending stocks numbers for U.S. corn and soybeans than those revealed this morning. Good pricing opportunities remain. Before the open, Dec ‘10 corn futures are $4.11; Nov ‘10 soybean futures are $10.15; and Dec ‘10 SRW wheat futures are $7.25; Dec ‘11 corn futures are $4.31; Nov ‘11 soybean futures are $10.04; and July SRW wheat futures are $6.88 per bushel.

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

Agronomic Crop Insects

Friday, August 13th, 2010

Joanne Whalen, Extension IPM Specialist;

Alfalfa and Grass Hay Crops
Be sure to watch for corn earworm, fall armyworm, beet armyworms as well as other defoliators. The following link provides a list of materials labeled for defoliators in these crops: . Before treatment, be sure to check all labels for the rate; comments on control under high populations and size of larvae; days to harvest as well as forage/silage restrictions, as well as other use restrictions. As far as fall armyworm, we have just gotten reports of grass hay fields being damaged by armyworms so fields should be watched closely after cutting for armyworm damage to the re-growth. Larvae must be small at the time of treatment to achieve effective control.

Corn Earworm (CEW) Alert
The potential for corn earworm pressure in soybeans is high statewide. Trap catches remain high throughout the state and moths can be found laying eggs in fields. With the continued high trap catches throughout the state, be sure to check all fields for earworms.

Consultants in Delaware as well as on the eastern shore of Maryland are reporting economic levels as well as in some cases extremely high levels of corn earworms in both full season and double crop fields. Remember, corn earworms can feed on the foliage and blossoms as well as the pods. The only way to know if you have an economic level will be to scout. 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. We also know that during the last CEW outbreak year, high levels of earworms completely stripped fields of all the leaves and blossoms. Therefore, it is critical that all fields be scouted for corn earworm. 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 ( which estimates a threshold based on the actual treatment cost and bushel value you enter.

During the past 3 seasons as well as this season, states to our south, including Virginia, have reported controls failures with pyrethroids for CEW control in soybeans. Up until 2009, poor control in our area has been the result of treating too late, treating large worms or using too low of a rate. If you use a pyrethroid for earworm control, be sure to use the highest labeled rate. In addition to the pyrethoids, Steward, Lorsban or Larvin could also be considered, especially if armyworms are in the mix. In some fields, fall armyworm and beet armyworm can also be found.

For more information on what is occurring in Virginia, you will want to look at the Virginina Ag Pest Advisory ( which is generally updated by Friday each week.

Some Ugly Tomato Fields

Friday, August 13th, 2010

Jerry Brust, IPM Vegetable Specialist, University of Maryland;

I have received samples, gotten reports, and have been in some really ugly tomato fields in the past two weeks. The fields consistently have similar appearances where the bottom third or half of the plants have dead, dark brown, often dried-up leaves (Fig. 1). There have been various reasons for some of the dead tissue. In one case plants had Pith necrosis that we talked about a few weeks ago, another field had bacterial spot that was not controlled very well, in another situation mites were at a very high density, but in many situations there was no plant pathological or insect related reason for the terrible looking field. No pathogen could be found in the stems or roots of the plants and only incidental pathogens or insects on the leaves. What seemed to be happening was a rapid decline of the plants over the last couple of weeks. It appears that the stress of this summer is catching up to some fields as they support a heavy fruit load at this time of the season. Additional factors appear to be lower than needed levels of irrigation and possibly the plants are running out of nutrients. It is hard to put a definitive finger on the cause other than the heat and drought seem to be reducing the plants ability to maintain healthy lower foliage. Much of the fruit on many of these plants is still in remarkably good shape although it goes downhill fast (Fig. 2). The bottom leaves on tomato plants are often used to help fill out fruit when times are tough for the plant, so that these leaves become weakened, yellow and very tough and leathery. This situation seems to be occurring here, but at a much accelerated rate of lower foliage decline. In this weather any additional stress on the plant is going to increase the possibility it declines rapidly. I do not have a sure-fire plan to remedy the situation other than to pick off the fruit load as much as is reasonably possible and increase irrigation levels as well as to feed the plants low concentrations of NPK. The plants are probably not going to recover to any great extent until the heat wave ceases, but you can maintain the plants until you harvest the fruit. The most important thing to do if your field looks like Figure 1 is to take plant samples to figure out exactly what you have. Whether it is a plant disease or insect problem or an environmental one, steps can be taken to remedy the situation, but you have to be sure what you are dealing with first.

Figure 1. Tomato field with the bottom half of the plants with dead leaf tissue

Figure 2. Tomato fruit on plants with dead bottom foliage

Watermelon Fruit Blotch

Friday, August 13th, 2010

Nancy Gregory, Plant Diagnostician; and Kate Everts, Vegetable Pathologist, University of Delaware and University of Maryland;

Bacterial fruit blotch on watermelon has shown up in Delaware for the first time this year. This disease is caused by the bacterium Acidovorax avenae subsp. citrulli, which is most commonly seed-borne. Fruit blotch is favored by warm, humid conditions. The typical symptoms include a dark olive green irregular stain on the fruit. It appears water-soaked, but can be dry. The blotch will spread in size, but usually doesn’t extend down into the flesh of the fruit. Older lesions may split open, and then fruit rot can occur from the entry of other bacteria and fungi. Once fruit matures, the waxy rind prevents infection, so infections seen now probably occurred at fruit set or in early fruit development. Fields ready for harvest should be kept dry, and severely affected fruit or those with splits or wounds to the rind should be culled. Contaminated seed or seedlings are the primary cause of infection, but the bacteria can survive on crop debris and weed hosts. On Delmarva, we have observed instances where the pathogen overwintered and survived on watermelon “volunteer” plants grown in alternate, non-host years. Fields with known infections should be rotated away from cucurbits, plowed, and weeds and volunteer watermelon plants controlled. Greenhouse sanitation and clean seedlings for the next year are important. Copper or Tanos (8.0 – 10.0 oz/A) applied every seven days will suppress disease progress.

Watermelon fruit blotch

Preserving the Late Set on Watermelons

Friday, August 13th, 2010

Gordon Johnson, Extension Vegetable & Fruit Specialist;

Watermelon maturity and harvest was accelerated this year by the high temperatures in June and July and there may be a shortage of late watermelons. With this in mind, many growers are trying to preserve later sets in early harvested fields to mature at the end of August or in early September. Success will depend on a number of factors.

First and foremost is the health and condition of the vines. Plants need to have an adequate amount of healthy leaf area to support watermelon fruit development. The leaves closest to the developing fruit are the most critical. If these leaves are in good shape, then an aggressive fungicide program is warranted to keep them healthy and provide photosynthates for the late set.

Previous harvest operations will have spread diseases in the field and caused wounds that further accelerated disease development. Older portions of watermelon vines with fungal infections will serve as reservoirs to infect healthy leaves making protection more difficult. Good coverage will be essential. Mix fungicides with some local systemic activity with a protectant fungicide. This time of year you may see the full mix of diseases including gummy stem blight, Alternaria, and anthracnose along with the potential for some late season diseases such as downy mildew and/or powdery mildew. The fungicide program that you choose needs to target diseases that are occurring in your field and in neighboring fields, so intensive scouting and correct diagnosis of existing diseases is critical.

In addition, mite, aphid, rindworm, and other insect populations may have built up to high numbers and aggressive control programs will also be needed to protect late sets.

It is also critical to evaluate the condition of the stems. Vines are damaged by trampling during harvest. When a vine is stepped on, it compromises the ability of that stem to carry water and mineral nutrients to leaves and fruits further down the vine. Areas with heavy foot traffic will have a lower percentage of saleable fruits from late sets because of this.

Another critical factor is the presence of any mature watermelons still attached to vines that were not harvested in prior trips across the field (melons were missed, had defects, too small, had damage, etc.). When a mature fruit is kept attached to a vine, it will delay the development of any later sets (due to hormone signals in the plant). Detaching or removing these melons will help later sets progress. A plant will mature 2-3 watermelons in the normal harvest window. To get a plant to produce more, all old fruits must be removed promptly.

Water is one of the most important factors in maturing late sets. Often, less attention is paid to irrigation during and after harvest operations. Beds are allowed to dry and vines are water stressed. This also shifts the hormone balance in the plant and can impede later sets or cause premature abortion of late sets. It is important to keep fields with later sets well watered and manage to irrigation closely.

Finally, additional fertilizer will be needed to promote the later sets, maintain healthy leaves, and promote fruit development. Nitrogen and potassium are the most critical in this regard. An additional 20-50 lbs of N/acre should be applied through the irrigation. 20-50 additional lbs of potassium per acre can also be of benefit, especially in light, low CEC soils (potassium is important for fruit quality).

Vegetable Crop Insects – August 13, 2010

Friday, August 13th, 2010

Joanne Whalen, Extension IPM Specialist;

NOTE – Be sure to check BLT catches in your area for corn borer and corn earworm catches – there has been a significant increase in trap catches over the past 10 day period. You can get updates by calling the Crop Pest Hotline (in state: 1-800-345-7544; out of state: 302-831-8851) or checking our website (

Continue to sample for cabbage looper, diamondback larvae, armyworms and Harlequin bug. Although the pyrethroids will provide control of Harlequin bugs they are not effective on diamondback. So be sure to scout and select controls options based on the complex of insects present in the field.

Lima Beans
Continue to scout for spider mites, stink bugs and lygus bugs. Be sure to sample for corn earworm larvae as soon as pin pods are present. A treatment will be needed if you find one corn earworm larvae per 6 ft-of-row. With the increase in local corn earworm catches we are starting to see an increase in larval populations.

Continue to scout all melons for aphids, cucumber beetles, and spider mites. We continue 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. As soon as 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: 1-800-345-7544; 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 continue to find aphids in fields and populations can explode quickly, especially where beneficial insect activity is low. 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. Just 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 (e.g. a pyrethroid). 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: 1-800-345-7544; out of state: 302-831-8851). A whorl stage treatment should be considered for fall armyworm when 12-15% of the plants are infested. We continue to find pockets of high fall armyworm infestations. 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.

Twilight Tour With Bees

Friday, August 6th, 2010

Twilight Tour with Bees
Delaware bees, crop pollination, and conservation
Monday, August 30, 2010     5:30 – 7:30 p.m.
Lister Acres (Hurd Family)
5417 Milford-Harrington Highway
Harrington, DE 19952

● Farm Tour: strawberries, melons, flower buffer strips, Heather Harmon Disque, Gordon Johnson, Emmalea Ernest, Bonnie MacCulloch

● Honey Bees: Dr. Debby Delaney, Bob Mitchell

●  Pesticide Safety: Joanne Whalen and Bill Cissel

● Practicality of conservation practices and making changes, Chuck Hurd

RSVP by August 25 to:
Plant Industries
Delaware Department of Ag
Dover, DE 19901
Phone: 302-698-4577

Presented by the Delaware Department of Agriculture and University of Delaware