Posts Tagged ‘18:13’

WCU Volume 18, Issue 13 – June 11, 2010

Friday, June 11th, 2010

PDF Version of WCU 18:13 – June 11, 2010

In this issue:

Vegetable Crop Insects
Vegetable Replanting Decisions
Cucurbit Downy Mildew Alert
Stem Girdling in Peppers
Postemergence Broadleaf Weed Control in Lima Beans
Cultivation and Postemergence Herbicide Treatment
Potato Disease Advisory #7 – June 9, 2010

Agronomic Crops
Agronomic Crop Insects
Wheat Disease Update
Check Soybean for Manganese (Mn) Deficiency
Clean Out the Sprayer
Liberty Link Soybeans Need Timely Sprays
Postemergence Control of Glyphosate Resistant Horseweed
Grain Marketing Highlights

2010 Weed Science Field Day


2010 Weed Science Field Day

Friday, June 11th, 2010

Wednesday, June 23, 2010     8:30 a.m.
Carvel Research & Education Center
16483 County Seat Hwy
Georgetown, DE 19947

The day will begin with registration at 8:30 a.m. at the Grove near the farm buildings and new office building on the north side of the road. We will start to view the plots at 9:00 am. Coffee, juices, and donuts will be provided. We will also provide sandwiches for lunch.

Grain Marketing Highlights – June 11, 2010

Friday, June 11th, 2010

Carl German, Extension Crops Marketing Specialist;

USDA Cuts Corn, Soybean, and Wheat Stocks
Ending stock projections for the ‘09/‘10 and ‘10/‘11 marketing years for U.S. corn, soybeans, and wheat were reduced in the June report from month ago levels. Soybean and wheat ending stock projections were in line with pre-report expectations. Corn ending stock estimates were lower than pre-report expectations.

Corn Analysis
U.S. corn ending stocks for the current marketing year are now estimated at 1.603 billion bushels, 135 million bushels less than the May estimate. The decline in the estimate for U.S. corn stocks is largely attributed to an increase in demand for ethanol use for both the ‘09/‘10 and ‘10/’11 marketing years. The estimate for U.S. corn ending stocks for the ‘10/‘11 marketing year was lowered 45 million bushels from the previous month, now projected at 1.573 billion bushels. USDA raised their season average farm price estimate for ‘10/‘11 marketing year corn by 10 cents a bushel on both ends of the price range, now estimated at $3.30 to $3.90 per bushel. The season average price for ‘09/‘10 marketing year corn was estimated at $3.45 to $3.65 per bushel.

For the ‘09/‘10 marketing year the estimate for Brazilian corn production was lowered .5 MMT, now estimated at 53 million metric tons. The estimate for Argentina corn production was increased 1.5 MMT, now projected at 22.5 MMT. For the ‘10/‘11 marketing year, USDA is now projecting corn production for Argentina at 21 MMT and Brazil corn production at 51 MMT. World corn ending stock estimates were reduced from last month for both marketing years. World corn ending stocks are now projected at 147.32 million metric tons (a reduction of 6.89 MMT) for the ‘10/‘11 marketing year and 143.41 MMT (3.63 MMT less than last month) for the ‘09/‘10 marketing year.

Soybean analysis
U.S. soybean ending stocks for the ‘09/‘10 marketing year were reduced 5 million bushels from last month, now estimated at 185 million bushels. That reduction was carried forward into the ‘10/‘11 marketing year with ending stocks now estimated at 360 million bushels, as compared to 365 million bushels a month ago. The season average farm price for U.S. soybeans was reported at $9.50 per bushel for the ‘09/‘10 marketing year and left unchanged from last month’s estimate at $8.00 to $9.50 per bushel for the ‘10/‘11 marketing year.

The Brazilian soybean production estimate for the current marketing year was increased 1 MMT from last month, now projected at 69 MMT. The Argentine soybean production estimate was left unchanged from last month at 54 MMT for a combined total production of 123 MMT for the ‘09/‘10 marketing year. World ending stocks for soybeans were increased for both the ‘09/‘10 (from 63.76 MMT to 65.47 MMT) and ‘10/‘11 marketing years (from 66.09 to 66.99 MMT).

Wheat Analysis
U.S. all wheat ending stocks were reduced 20 million bushels for the current marketing year, now estimated at 930 million bushels. Ending stock projections for ‘10/‘11 marketing year wheat were reduced by 6 million bushels, now projected at 991 million bushels. The season average farm price for U.S. wheat was reduced by 10 cents per bushel on the low end and 30 cents per bushel on the high end of the price range for ‘10/‘11 marketing year wheat. The season average farm price for the ‘09/‘10 marketing year was reported at $4.85 per bushel.

Canadian and Australian wheat production estimates were left unchanged from last month at 26.5 and 22.5 MMT for the current marketing year and 24.5 and 22 MMT, respectively, for the ‘10/‘11 marketing year. The estimates for world wheat ending stocks were reduced for both marketing years. World ending stocks for ‘09/‘10 marketing year wheat are now estimated at 192.9 MMT, .47 MMT less than last month. World ending stocks for all wheat for the ‘10/‘11 marketing year are now projected at 193.93 MMT, 4.16 MMT less than last month’s estimate.

Marketing Strategy
The June supply and demand report can be viewed as bullish for corn, bullish old crop soybeans, bearish new crop soybeans, and bearish for wheat. However, commodity traders are not likely to pay much attention to this report due to outside market forces, the weather, and the soon to be released June 30 Planted Acreage report which could increase acreage and yield estimates for 2010 corn and soybean production. Currently, new crop Dec ‘10 corn futures are trading at $3.61; Nov ‘10 soybean futures at $8.91; and July SRW wheat at $4.31 per bushel. Nearby old crop July corn futures are trading at $3.41; and July ‘10 soybean futures are trading at $9.32 per bushel. The nearby U.S. dollar index is at 87.18; nearby crude at $74.38; and the Dow is trading at 10,095.

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

Postemergence Control of Glyphosate Resistant Horseweed

Friday, June 11th, 2010

Mark VanGessel, Extension Weed Specialist;

Options for controlling horseweed resistant to glyphosate after the soybeans have emerged are very limited. Liberty Link soybeans are an exception, because Ignite 280 is fairly effective on horseweed (be sure to keep your rates up).

For non-Liberty Link soybeans the options are very limited. FirstRate or Classic are only effective on small, newly emerged seedlings. However, neither FirstRate nor Classic, will consistently kill large horseweed plants nor plants that were “burned off” and are recovering. These herbicides may provide some suppression, but results have been quite erratic the past few years. Horseweed plants are generally not very tolerant of shade and most soybeans will begin to canopy over the horseweed and out-compete them. In most cases, I have recommended to not spray emerged horseweed plants with another herbicide. Rather, make postemergence applications of glyphosate based on need to control other weed species. Additional glyphosate applications will provide some suppression of horseweed and give the soybeans a chance to outcompete them.

Liberty Link Soybeans Need Timely Sprays

Friday, June 11th, 2010

Mark VanGessel, Extension Weed Specialist;

Although glufosinate and glyphosate may sound similar they are very different herbicides and we need to think of them differently. (Glufosinate is active ingredient in Ignite 280 and glyphosate is active ingredient in Roundup)

A few reminders for those growing Liberty Link soybeans:

● Ignite works best on hot sunny days
● Do not apply within 2 hrs of sundown
● Ignite will control a broad-spectrum of weeds, but is not very effective on larger weeds (applications should be made as weeds approach 4 inches in height)
● Ignite is not as effective on larger grasses (applications made to grasses over 6 inches may result in poor control)
● Two applications of 22 fl oz can be made OR a single application of 29 to 36 fl oz (do not exceed 44 fl oz/season)
● Apply with AMS
● Do not apply within 70 days of harvest
● Spray coverage is important for highest level of control

Clean Out the Sprayer

Friday, June 11th, 2010

Mark VanGessel, Extension Weed Specialist;

I have had a number of fields this year that were injured from low rates of herbicide remaining in the tank from the previous application. Most of these situations occur when the spray is mostly sprayed out and rather than rinse out the tank, additional water is added with the thought that “the little amount that remains will be diluted enough”. In cases with a highly sensitive crop, and in combination with a translocated herbicide, severe injury can occur. Also, a crop that is developed to be resistant to one herbicide, does not make it resistant to all herbicides (i.e. Liberty Link is not resistant to glyphosate). When in doubt, clean out.

Check Soybeans for Manganese (Mn) Deficiency

Friday, June 11th, 2010

Richard Taylor, Extension Agronomist;

An interesting fact came up recently about the research retired Purdue University plant pathologist Don Huber has done linking glyphosate and reduced uptake of several nutrients in field crops. I found the notation that significantly lower tissue levels of the micronutrients manganese (Mn), zinc (Zn), and iron (Fe) are being taken up by the field crops he studied. In Delaware, we frequently see Mn deficiency symptoms on soybeans, especially on sandy soil or where the soil pH is maintained near neutral or above.

Just yesterday driving back from the University of Delaware Research and Education Center, I noticed Mn deficiency symptoms showing up in several fields. Manganese deficiency is characterized by dark green veins and light green (mild deficiency) to yellow (moderately severe deficiency) to white (severe deficiency) interveinal leaf tissue. The symptoms often are most severe on the most recently emerged leaves. Manganese deficiency symptoms are similar to the deficiency and toxicity symptoms of some of the other micronutrients.


Photo 1. Moderately severe interveinal chlorosis on no-till single-crop or full-season soybean. Note dark green veins with tissue between veins yellow. Younger leaves are most affected since Mn is not mobile in the plant.

Yield reductions can be avoided to a large degree by early diagnosis and treatment with foliar application of Mn. Multiple applications of foliar Mn may be needed especially when Mn deficiency is severe. If enough leaf area is present to absorb adequate Mn, a single application higher rate (1 to 2 lb Mn/acre) was shown to be effective by Virginia and North Carolina researchers. Ignoring or not catching the problem until later in the season can not only reduce yield potential but make a foliar application more difficult and possibly more expensive since driving over the soybeans may cause damage on drilled beans. You may need to treat early season symptoms several times since the leaf area available to absorb Mn is limited so always rescout treated fields to be sure Mn deficiency does not reappear after treatment.


Photo 2. Moderately severe interveinal chlorosis on no-till single-crop or full-season soybean. Note dark green veins with tissue between veins yellow.

Where the symptoms are widespread and moderate to severe, foliar Mn applied at 1 to 2 lbs Mn per acre can boost yields significantly. Since the crop is still in the vegetative stage, mild to moderate symptoms can be alleviated with a 0.5 lb Mn per acre foliar spray. Researchers in Delaware, Virginia, and North Carolina have shown that soybeans are very responsive to foliar Mn especially when applied well before soybeans begin to bloom.

Even if you do not apply foliar Mn, you should be making note of which fields and where in the field symptoms occur so you can monitor these areas in the future. If wheat or barley are to be planted this fall, careful early monitoring will allow you to apply Mn to the small grains before they are severely injured by Mn deficiency. You should also note the areas so you can do soil testing to determine the underlying problem. Check to see if the native Mn concentration in the soil is too low or whether the soil pH is too high since the higher the pH the lower the availability of Mn in the soil. Also, any factor restricting root growth (compaction, drought, etc.) can aggravate Mn deficiency symptoms and should be corrected.

Dr. Joseph Heckman at Rutgers University is writing a series of articles on Mn deficiency in Rutgers Plant and Pest Advisory publication. These publications are available on the web through the Rutgers New Jersey Agricultural Experiment Station. A recent article (Vol. 16, No. 7, page 3) showed research Dr. Heckman conducted comparing manganese sulfate and chelated manganese and this article can be found at the following web address:

Wheat Disease Update – June 11, 2010

Friday, June 11th, 2010

Bob Mulrooney, Extension Plant Pathologist;

With the dry weather, wheat is beginning to turn in most area of the state. It looks like scab will not be an issue this year. Leaf rust and stripe rust did appear, late for the most part, but should have minimal effect on yield if the wheat was not sprayed.

Agronomic Crop Insects – June 11, 2010

Friday, June 11th, 2010

Joanne Whalen, Extension IPM Specialist;

Continue to sample for potato leafhoppers on a weekly basis. We are now finding adults and nymphs in fields. Although both life stages can damage alfalfa, the nymphs can cause damage very quickly. Once plants are yellow, yield loss has already occurred. The treatment thresholds are 20 per 100 sweeps on alfalfa 3 inches or less in height, 50 per 100 sweeps in 4-6 inch tall alfalfa and 100 per 100 sweeps in 7-11 inch tall alfalfa.

Field Corn
We have had a number of reports of cereal leaf beetle adults moving out of small grains and feeding on the edge of corn fields. Although we do not have any firm thresholds for this insect on corn, as a general guideline controls may be needed on corn for feeding damage if you find an average of 10 beetles per plant and 50% of the plants exhibit feeding damage. Last year I was asked about the potential for cereal leaf beetles to vector disease in corn. In the Midwest, it has been reported that the adult beetles is a vector of maize chlorotic mottle virus (MCMV) that causes corn lethal necrosis disease. Thresholds would be much lower if this disease is an issue. To date, we still are not aware of this occurring in Delaware; however, be sure to let us know if you find potential problems.

In checking fields this week, we have also seen a number of fields with stink bug damage to whorl stage corn. Fortunately, the damage has been minimal in most fields. In some cases, it has been thought to be herbicide injury and/or damage from wireworms. Please be sure to check the following link for pictures of damage

Be sure to sample seedling stage beans for bean leaf beetles, grasshoppers and thrips. We have seen an increase in bean leaf beetle feeding damage, although it has been generally lower compared to last season. With the warmer temperatures, be sure to watch for an increase in populations. As barley is harvested and soybeans are planted, these fields will be especially susceptible to attack by grasshoppers which can cause stand loss. If stand reductions are occurring from plant emergence to the second trifoliate, a treatment should be applied. Although no precise thresholds are available, a treatment maybe needed if you find one grasshopper per sweep and 30% defoliation from plant emergence through the pre-bloom stage. As a general guideline, a treatment may be needed for bean leaf beetle if you observe a 20 – 25% stand reduction and/or 2 beetles per plant from cotyledon to the second trifoliate stages. These treatment thresholds should be reduced if virus is present or you suspected virus the previous season.

As far as thrips, information from North Carolina indicates that “soybean thrips and other thrips species can feed and reproduce on the leaves and buds of soybean seedlings. Their feeding creates bleached-out lesions along the leaf veins and gives a silvery/bronzed appearance to the leaf surface when damage is severe. These insects are very small (less than 1/10 inch) and are torpedo shaped. While thrips always occur on soybean seedlings, it is only during outbreak years that they cause concern. In particular, during dry weather and on earlier planted full-season soybeans, thrips populations can explode when plants are growing slowly. Under these circumstances thrips injury will occasionally kill seedlings. Other stressors, such as nutrient deficiencies and herbicide injury, can add to thrips damage and cause plant loss.” Yellowing can occur from thrips but there are also a number of other factors that can cause yellowing, so it is important to scout fields to identify what is causing the yellowing. Although no precise thresholds are available, as a general guideline, treatment may be needed if you find 4-8 thrips per leaflet and plant damage is observed.

Potato Disease Advisory #7 – June 9, 2010

Friday, June 11th, 2010

Bob Mulrooney, Extension Plant Pathologist;

Disease Severity Value (DSV) Accumulation as of June 8, 2010 is as follows:

Location: Art and Keith Wicks Farm, Rt 9, Little Creek, Kent County.
Green row: May 6

Date Daily DSV Total DSV Spray Recs Accumulated
5/27-5/28 1 30 10-days -
5/29-5/30 1 31 10- days -
5/31 0 31 10-days 199
6/1 1 32 10-days 206
6/2 0 32 10-days 214
6/3-6/5 0 32 10-days 232
6/6–6/8 0 32 10-days 257

Maintain the recommended spray interval. At 300 P-days fungicide sprays will be needed to control early blight. This should occur this week. At this point weekly fungicide applications would be suggested. There have been no confirmed reports of late blight on potatoes in the region.

* P days- We use the predictive model WISDOM to determine the first fungicide application for prevention of early blight as well. The model predicts the first seasonal rise in the number of spores of the early blight fungus based on the accumulation of 300 physiological days (a type of degree-day unit, referred to as P-days) from green row. To date, 257 P-days have accumulated at the site. Once 300 P-days have accumulated, the first fungicide for early blight control should be applied. This usually occurs when rows are touching.

If pink rot or leak is a concern and no pink rot fungicide was applied at planting consider applying one of the following when potatoes are nickel-sized and repeating 14 days later. Apply in as much water as possible (20-30 gal/A): Mefanoxam/chlorothalonil (Ridomil/Bravo) 2 lb/A, or Ridomil Gold/MZ 2.5 lb/A, or Ridomil Gold/Copper 2 lb/A. If Platinum/ Ridomil Gold was applied at planting the label allows one foliar application of one of those products at tuber initiation if conditions warrant.

The Spray Recs column in the table is also generated by the WISDOM software program. This recommendation combines the DSV accumulation for late blight as well as the P-day accumulations for early blight and computes a spray recommendation. This is presented as a guide only. Spray decisions should be made with local conditions in mind and this information can help to determine if disease conditions are favorable.

For specific fungicide recommendations, see the 2010 Delaware Commercial Vegetable Production Recommendations Book.