Posts Tagged ‘18:15’

WCU Volume 18, Issue 15 – June 25, 2010

Friday, June 25th, 2010

PDF Version of WCU 18:15 – June 25, 2010

In this issue:

Vegetables
Vegetable Crop Insects
Insecticide Update: Endosulfan (Thionex)
Magnesium Deficiencies in Vegetables
Cucurbit Downy Mildew Update
Watch for Phytophthora Fruit Rot on Cucurbits
Powdery Mildew on Cucurbits
Potato and Tomato Late Blight Update
Watermelon Gummy Stem Blight Fungicide Programs in 2010
Blossom End Rot in Tomatoes
Tomato Pith Necrosis Found in Maryland

Agronomic Crops
Agronomic Crop Insects
Soybean Rust Update
Manganese Applications With Postemergence Glyphosate
Roundup Ready in Double-Crop Soybeans
Grain Marketing Highlights

Announcements
Soybean Cyst Nematode Workshop – August 3

Weather

Grain Marketing Highlights

Friday, June 25th, 2010

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

Summer Impacts Commodity Marketing
The beginning of summer is always a delightful time of year for those of us who love the great outdoors. Simultaneously, it is often times the beginning of very uncertain and exciting times in the commodity markets. Volatility in commodity prices can rise with summer temperatures. The rise in volatility can result in catching a higher price for a portion of this year’s pre-harvest crop sales, something akin to catching a wave. This year is of no exception. Crop conditions throughout the major portion of the Corn Belt have been and continue to be nearly ideal with just a tad of trouble indicated in this week’s Weekly Crop Conditions report. U.S. corn crop conditions for the week ending June 20 were lowered 2 points in the good category, now rated 75 percent good to excellent (77 percent a week ago). U.S. soybean crop conditions were lowered 4 points in the good category to 69 percent good to excellent, compared to 73 percent a week ago. Even though the ratings were lowered, preliminary indications from private sources since the release of the report on Monday are suggesting that we could see an upswing in these ratings in next week’s report. Generally speaking, the main portion of the Corn Belt is experiencing garden growing conditions while most of the problems belie the fringes of the Corn Belt. Eventually, depending to some degree on whether demand outpaces supply for the ‘10/‘11 marketing year, these types of ratings for crop conditions will result in prices moving lower as summer and crop size progresses? We may get a better handle on the answer to that question upon release of the June 30 Planted Acreage and USDA’s July 9 Supply/Demand reports.

USDA Export Sales Report 06/24
Pre-report estimates for weekly export sales of soybeans (combined old-crop and new-crop) ranged from 7.3 to 16.5 million bushels. The weekly report showed old-crop export sales of 11.3 million bushels, above the 3.6 million bushels needed this week to stay on pace with USDA’s demand projection of 1.455 billion bushels. Total shipments of 8.8 million bushels were below the 9.9 million bushels needed this week. This report should be viewed as neutral.

Pre-report estimates had weekly corn export sales at 25.6 to 39.4 million bushels. The weekly report showed old-crop export sales of 44.2 million bushels, well above the 9.3 million bushels needed this week to stay on pace with USDA’s demand projection of 1.95 billion bushels. Total shipments of 32.2 million bushels were below the 46.5 million bushels needed this week. This report should be viewed as neutral to bullish.

Pre-report estimates for wheat exports ranged between 9.2 to 16.5 million bushels. The weekly report showed total export sales of 26.5 million bushels, well above the 14.2 million bushels needed this week to stay on pace with USDA’s projected 900 million bushels. Shipments of 21.0 million bushels were below the 17.6 million bushels needed this week. This report should be viewed as neutral to bullish.

Market Strategy
As of Friday of last week, due to the wet conditions in the Corn Belt that resulted in a slight lowering of U.S. crop conditions for corn and soybeans, the commodity markets were thought to be getting positive price signals. Outside market forces, the Dow, the dollar value, and crude oil prices also played a role. New crop corn futures prices are now 12 cents lower than last week, while new crop soybean and SRW wheat prices are within one cent per bushel of last week’s price levels. New crop soybeans did a brief stint about a dime higher than yesterday’s close on June 21. Dec ‘10 corn futures closed at $3.65 per bushel; Nov ‘10 soybeans at $9.23; and July SRW wheat at $4.62 per bushel in yesterday’s day trading. Outside market forces have turned price negative to commodity prices thus far this week. July corn needs to close over $3.85 on June 30th to post a monthly reversal higher. July soybeans need to close over $9.92, and SRW wheat over $5.12 per bushel. Private sources are suggesting that China’s decision to float their currency should support U.S. commodity prices. So that raises the question, “Is the higher reversal in commodity prices possible?” Answer: “In the summer months, anything is possible concerning commodity prices.”

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

Roundup Ready in Double-Crop Soybeans

Friday, June 25th, 2010

Mark VanGessel, Extension Weed Specialist; mjv@udel.edu

Planting of soybeans following small grains is under way. Remember to start off clean with a burndown. Trying to time the glyphosate application to provide both “burn-down” and in-crop weed control often does not work well. Also, given how many weeds are in many of the wheat fields, a knockdown will be needed in most situations. Timing of in-crop application of Roundup Ultra or Touchdown is not as critical as with full-season soybeans. Options include glyphosate, Ignite 280, or Gramoxone Inteon. Depending on the weeds present, additional herbicides may be needed. For instance if horseweed is present, Ignite 280 maybe an option; or if glyphosate is used, Canopy or Canopy EX should be included to help control horseweed.

Postemergence applications from 14 to 28 days after planting resulted in similar weed control and yield in studies conducted with the Delaware Soybean Board. Check your fields about 14 days after planting because weeds not killed with the burndown treatment will be starting to re-grow. Then the second application can be made before the weeds become too large.

Manganese Applications With Postemergence Glyphosate

Friday, June 25th, 2010

Roundup Ready soybeans may require a postemergence application of glyphosate and a manganese application about the same time. These glyphosate products can be tankmixed with manganese with some precautions. The manganese products can bind with glyphosate in the spray tank and reduce glyphosate’s effectiveness. The form of manganese has an impact. Manganese chelated with EDTA does not appear to affect the performance of glyphosate, but other forms of manganese do. The addition of ammonium sulfate can overcome the problem. Thus, when tankmixing glyphosate with manganese, use an EDTA form of manganese or add ammonium sulfate to overcome the reduced weed control. When using ammonium sulfate be sure to add the ammonium sulfate to the tank first and add the glyphosate last.

Soybean Rust Update

Friday, June 25th, 2010

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

Soybean rust was confirmed June 10, in the US for the first time this season on soybean in Hidalgo County, Texas. Rust has also been confirmed on soybean in the neighboring Mexican state of Tamaulipas. Rust was just detected in Mobile AL on kudzu on June 23. Conditions for soybean rust are still very unfavorable in the Gulf States. If you are interested in the movement of soybean rust consult the ipm PIPE website at http://sbrusa.net.

Agronomic Crop Insects – June 25, 2010

Friday, June 25th, 2010

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

Alfalfa
Continue to sample for potato leafhoppers on a weekly basis. 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
In recent years, we have seen an increase in stinkbug damage to developing corn ears, especially when fields are adjacent to small grain fields. We are continuing to survey fields to evaluate the extent of the damage this season. Information from the University of Georgia, where they have experienced problems, indicates that:

(a) Corn is most susceptible to stink bug injury during ear formation before tasseling.

(b) Bugs will feed through the sheath, causing a dead spot on the ear. As the ear expands it becomes distorted and curves, usually outward.

(c) Feeding during silking and pollen shed also will kill kernels on the ear. Once the ear has elongated, stink bug feeding during the blister and milk stages blasts individual kernels usually causing them to abort.

(d) Although we have not developed thresholds for our area, the following thresholds are used in the South : 25% infested plants (1 bug per 4 plants) as a threshold during ear elongation to pollen shed and 50% infested plants (1 bug per 2 plants) during the later part of pollen shed and blister/milk stage.

(e) Initially stink bugs tend to be more prevalent on the field edge, so only a perimeter spray may be needed.

Soybeans
Be sure to sample fields in the seedling stage for bean leaf beetles, grasshoppers and spider mites. Grasshopper populations are starting to increase, especially in no-till fields. As barley and wheat are harvested and soybeans are planted, these fields will be susceptible to attack and grasshopper feeding can often 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 may be needed if you find one grasshopper per sweep and 30% defoliation from plant emergence through the pre-bloom stage. Numerous products are labeled for grasshopper control including a number of pyrethroids, dimethoate, Lorsban, Orthene 97 and Sevin XLR. Be sure to check all labels carefully before combining insecticides and herbicides since there are a number of restrictions on the labels.

Continue to watch carefully for spider mites. We are finding fields with economic levels of mites, both on field edges and in some cases in field interiors – so be sure to scout the entire field to make a treatment decision. Labeled materials include dimethoate, Lorsban, Hero (zeta-cypermethrin + bifenthrin) as well as a number of stand alone bifenthrin products (not all may be labeled so be sure to check the label). All of these products need to be applied before mites explode. Be sure to read the labels for use rates and restrictions – there is a limit on the number of applications as well as the time between applications on all of the materials labeled for spider mite control.

Tomato Pith Necrosis Found in Maryland

Friday, June 25th, 2010

Jerry Brust, IPM Vegetable Specialist, University of Maryland; jbrust@umd.edu and Karen Rane, Director UMD Plant Diagnostic Laboratory

In the last few days we have received tomato samples that have the same unusual disease called Tomato pith necrosis. Tomato pith necrosis is caused by the soilborne bacterium Pseudomonas corrugata. Pith necrosis has occurred infrequently in Maryland over the past few decades. The disease usually is found in early planted tomatoes when night temperatures are cool, but the humidity is high, and plants are growing too rapidly because of excessive nitrogen application. Once night temperatures warm up, the plants usually outgrow the problem. We have had an early spring, which has allowed many growers to plant their crops 2-3 weeks earlier than normal. We then had cool nights in May and at times high humidity. In the field, diseased plants occur randomly with initial symptoms often being seen as the first fruit clusters reach the mature green stage. Symptoms include chlorosis (yellowing) of young leaves and shoots, followed by wilting of the infected shoots in the upper part of the plant canopy (Fig. 1). This wilting is usually associated with internal necrosis at the base of the stem. Black streaking may be apparent on the surface of the main stem, which often splits (Fig. 2). When the stem is cut open along its length the pith will be discolored, and may have hollow areas (Fig. 3). There is often prolific growth of adventitious roots in the stems with discolored pith, and the stems may appear swollen.

There is not much that can be done for control of pith necrosis. The best practice is prevention by avoiding the use of excessive amounts of nitrogen in tomato, especially early in the season when nights are still cool. Using plant activators such as acibenzolar-S-methyl (Actigard) have resulted in 55% disease reductions, but applications must be started before symptoms appear. There is some evidence that the pathogen may be seedborne, but more research is needed on the epidemiology and management of this disease.


Figure 1. Whole plant symptoms of tomato pith necrosis


Figure 2. Splitting of the main stem and darkened pith caused by tomato pith necrosis


Figure 3. Discolored pith and prolific adventitious root growth cause by tomato pith necrosis

Blossom End Rot in Tomatoes

Friday, June 25th, 2010

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

This is just a quick reminder that we are in very dry conditions right now and tomato plants are putting on large fruit at the same time they are flowering profusely. Everyone knows that blossom end rot is caused by too little calcium in the fruit while it is developing, usually from the time of flowering until it is the size of a quarter. Most of the blossom end rot I have seen in tomato is due to too little water supplied to tomatoes during dry, very hot periods like we are having now. Some varieties are much more sensitive to dry conditions and will show severe blossom end rot symptoms while other varieties do not. Your tomato plants are going to need more water than you may be used to giving them over the next few weeks if conditions remain hot and dry.


Blossom end rot on tomato fruit

Watermelon Gummy Stem Blight Fungicide Programs in 2010

Friday, June 25th, 2010

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

Our weather has not been highly conducive to gummy stem blight or anthracnose in the last two weeks. Therefore, under low disease pressure a good strategy is to apply Bravo on a 7-day schedule. Alternatively, our trials over many years have demonstrated that under low disease pressure the spray intervals can be lengthened. Following the weather forecaster ‘MELCAST’ http://mdvegdisease.umd.edu/forecasting/index.cfm can help determine the safe interval that can be used without the likelihood of risking disease increases.

There are several fungicides available for gummy stem blight management. Although several products are available, the usefulness of some of these products is limited by resistance development in the pathogen. On Delmarva we have confirmed the presence of resistance in Didymella bryoniae, the pathogen, to fungicides in the FRAC code group 11 (strobilurins, including Quadris and Cabrio) and FRAC code 3 (demethylation inhibitors or DMIs, including Topsin M). Resistance to Pristine exists in Georgia, and therefore Pristine is not recommended in that state. We have not yet detected resistance to Pristine here. However many of our transplants are grown in the south and it would not be surprising to find that resistance has been introduced here.

The following are fungicide programs that performed well in trials in Maryland and other areas in the southeast US in 2009:

● Switch 14 fl oz/A (1 day PHI; FRAC codes 9 and 12) alternated with Bravo

● Folicur 8 fl oz/A (7 day PHI; FRAC code 3) alternated with Bravo

● Inspire Super at 20 oz/A (7 day PHI) alternated with Bravo (Inspire Super is a new product that has two active ingredients. Although one component is in the FRAC code 3 group – Inspire Super performed very well in 2009.)

● Pristine 12.5–18.5 oz/A (0 day PHI; FRAC codes 11 and 7) alternated with Bravo (Pristine continues to perform very well in my trials -it usually ranks at the top, although it is not always significantly better than other products. However, because it performs very poorly in Georgia trials and because of the potential for resistance development, use caution and monitor disease levels carefully, if you choose to use Pristine.)

Watermelon is susceptible to other diseases as well. Scout for downy mildew, Phytophthora fruit rot and powdery mildew. The presence of these diseases will require additional fungicide applications with products with different modes of action.

Potato and Tomato Late Blight Update

Friday, June 25th, 2010

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

Late blight on tomatoes was found on Long Island in a home vegetable garden this past weekend. There have been no reports of late blight in DE, NJ or eastern shore VA to date. The high temperatures this week (above 90°F) are not favorable for late blight.