Small grain harvesting is well underway. In my travels across the state, I’ve noticed a number of weeds popping their heads above the small grain canopy. Last fall was a very wet fall, and small grain plantings across the state were hampered by the rainfall. A number of acres never got planted, while those that did, were not the best in terms of stand counts. Where stands were thin and sunlight was able to penetrate the canopy, weeds developed. One of the weeds I’ve seen more often than not is horseweed. Horseweed, also known as marestail or stickweed, has a peculiar germination period. On the Eastern Shore, over 50% of the plants will germinate in the fall. On the Western Shore, that is not the case. Most of the plants will germinate during the months of April, May and June. While many growers may have sprayed Harmony or Harmony Extra, they did little to none to stop the growth and/or germination of this weed. Many of you reading this article know that we have glyphosate (trade names – Roundup, Touchdown, and many generics) resistant horseweed across the state. While pockets of glyphosate-resistant horseweed plants were first identified in 2000, this plant spread across the entire Eastern Shore within a matter of 3 years. Now, Southern Maryland and many parts of the Piedmont area of the state are battling this plant. On the Eastern Shore, fall applications of products like 2,4-D will kill the initial flush of weeds that develop. On the Western Shore, with the lack of fall germination, growers do not have that luxury. Thus, knock-down programs are needed where no-till programs are in place. Small horseweed plants can be controlled with Gramoxone Inteon. However, many growers elect to add 2,4-D to their tank-mix for control of other emerged broadleaf weeds. While this is not a problem where corn is planted, there are restrictions where soybeans are utilized. In general, most growers will use one-half to one pint per acre of an ester formulation. Here, the preplant interval is 7 days between application and the planting of soybeans. This would be the same preplant interval whether you mix 2,4-D with Gramoxone Inteon or with a glyphosate formulation. Recently, Liberty-Link soybeans and the herbicide called Ignite 280 came into the marketplace. In my mind, this is a tremendous boon to where growers are faced with the challenges of controlling glyphosate-resistant horseweed. Ignite 280 is extremely active on emerged horseweed plants and can be used as a burndown herbicide in place of Gramoxone Inteon or glyphosate. Even in the situation where a grower used Gramoxone or glyphosate as the burndown product of choice, if Liberty-Link soybeans were planted, one could go in overtop of the crop with Ignite 280 and realize successful control. Keep in mind the label states that you use Ignite 280 as a burndown product or as an in-crop postemergence application. We don’t want to see the same scenario develop where glyphosate was used as a burndown herbicide and as an overtop herbicide in the

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

June 17, 2010 Volume 1, Issue 6

Horseweed Management  1‐2 

A Potential Early Season Bully of Soybeans  2‐3 

Small Grains Testing Requirements for Potential Losses  3 

Crop Reports  3‐4 

Upcoming Events  4 

Did You Know  4 

In this issue

Horseweed Management Dr. Ronald L. Ritter, Extension Weed Control Specialist

Cont. pg. 2

Agronomy News - June 17, 2010 2

same season. It was the continued, multiple applications of glyphosate that resulted in the emergence of weeds resistant to glyphosate. We do not want to see this happen with Ignite 280. I’ve examined the use of Ignite 280 on the control of glyphosate-resistant horseweed for years. Throughout this time period, I have achieved 100% control of horseweed plants, even in worse case scenarios, where the plants were knee-high. However, this spring, I have seen some regrowth from horseweed plants treated with Ignite 280. Why? I feel that a number of situations have developed that may cause the regrowth noted this spring. First of all, we have had a very hot, and dry spring for the most part. Under these conditions, plants will “harden up.” What does that mean? Under hot, dry conditions, plants want to survive. Their ultimate goal is to flower and set seed. In order to survive, they put their plant systems under alert in order to conserve water. While many things can occur, more often than not, they will create a heavier waxy layer on the surface of the leaves and shut their breathing apparatus (called stomates) down. This creates a harder barrier for herbicides to penetrate. Secondly, Ignite 280 has limited movement in the plant. Good coverage is required for products like this. Many of you may remember when Paraquat (now called Gramoxone Inteon) first came out. It required a minimum of 40 gallons of spray material per acre for adequate control. With that amount of spray volume, Paraquat did a tremendous job controlling

most weeds we encountered in a no-till situation. What are we using today? In order to get across as many acres as possible, we are using less and less gallons of spray material per acre. It’s not unusual to see 8, 10 or 12 gallons of spray volume used per acre. This is just not enough spray volume for products like Ignite 280 which has limited movement throughout the plant.

One other product that is becoming known among the glyphosate-resistant horseweed products comes from the Kixor line of materials recently introduced from BASF. The product is called Sharpen. When used in combination with your knock-down product of choice, it can effectively add to the control of emerged horseweed plants. This is especially useful where you are in a 2,4-D sensitive area. As many of you know, 2,4-D can volatilize and drift. If sensitive plant material is within reach, 2,4-D can damage a variety of crops as well as a host of other horticultural plantings. Unfortunately, on coarse soils, with less than 2% organic matter, there is a 30 day preplant restriction. For optimum control

with Sharpen, the addition of a methylated seed oil plus ammonium sulfate is recommended. Weeds will continue to develop resistance to our arsenal of herbicides. Many of you reading this article are battling triazine-resistant weeds like pigweed and common lambsquarters. After years of using products like Scepter and Pursuit, we started to see a number of weeds resistant to these products as well. Some of you are battling Hoelon-resistant Italian ryegrass, and recently chickweed resistant to products like Harmony and Harmony Extra. In the case of horseweed, we did have a backup tool for postemergence control in soybeans. The product is called FirstRate. However, we have now developed pockets of horseweed resistant to not only glyphosate, but FirstRate as well. This is Mother Nature’s way of saying, “Survival of the Fittest.” Keep in mind that with any herbicide management program, you need to consider several things. These would be the following: rotate crops, rotate herbicides with different modes of action, if using a single mode of action product – limit its use to one application every year – and if possible – add another product to it with a different mode of action, consider tillage, scout for weed escapes, do not use herbicides above labeled rates, and if you can – utilize herbicides that have numerous sites of action within plants – products like 2,4-D and dicamba – and minimize those that have a single mode of action.

Cont. pg. 3

A Potential Early Season Bully of Soybeans Dr. Cerruti R2 Hooks, Extension Entomologist

An Uninvited Playground Guest In the early lives of soybean plants, insects may begin inhabiting their play ground soon after

emergent. But most often, insects that show up early at the soybean playground for a free leguminous meal seldom pose any significant threat to soybeans. That's because soybeans can tolerate a considerable loss of many young plants, and defoliation is not much of a concern

unless greater than 30 percent of the foliage is eaten before blooming initiates. Though, thrips typically hangout in the soybean park when young seedlings are present, it is only during outbreak years that they ruin the soybean park attendance. Yes, thrips can be an early

Agronomy News - June 17, 2010 3

Small Grains Testing Requirements for Potential Losses By Maryland Department of Agriculture

Last year Maryland farmers experienced significant crop losses due to vomitoxin contamination. As grain harvest is underway, the Maryland Department of Agriculture reminds grain dealers and farmers to be aware of handling and testing requirements to ensure appropriate crop insurance coverage for grain contamination losses. Vomitoxin (deoxynivalenol toxin), may be produced in wheat and barley grain infected by the fungus, Fusarium head blight (FHB) which is better known as scab. Federal crop insurance covers losses from vomitoxin, aflatoxin and fumonsin depending upon severity. However, producers must follow detailed handling and testing requirements developed by the U.S. Department of Agriculture Risk Management Agency (RMA). This harvest season, please keep in mind the following points:

• As soon as a vomitoxin, aflatoxin or fumonsin issue is discovered, insured farmers should contact immediately their crop insurance agent for instructions on grain handling so that they do not jeopardize their potential loss claim.

• The presence of the toxin must be the result of an insured cause.

• Grain with vomitoxin can be tested for crop insurance purposes while

it is still in the field or after it is placed in on-farm storage.

In 2009, Maryland received federal crop disaster designation for 10 counties due to vomitoxin contamination resulting from wet weather that occurred in May and June 2009. Persistent spring rain throughout most of the State caused significant contamination in wheat and barley in the form of vomitoxin, which can make the harvested wheat unmarketable for milling purposes and both harvested wheat and barley unusable as feed. Farmers in the disaster designation areas experienced market value losses ranging from 30 to 55 percent.

Cont. pg. 4

bully of soybean and are likely to flex their puny little muscles on the playground when the weather is dry, especially during the first 6 weeks of the soybean’s life. Otherwise, thrips typically go unnoticed and are seldom problematic. Thus, if soybean plants are already weakened by thirst due to drought, large gangs of thrips can stunt or kill seedlings. Further, man-made stressors, such as herbicide injury play in the hands of bullies by adding to thrips damage and may cause soybean to succumb to thrips presence. These tiny (< than 1/10 inch) torpedo shaped thugs injure these helpless soybean plants by rasping off the outer layer of their leaves and sucking out their juices. Action threshold for playground bullies When there are no snitches in the playground, you need to spot these early

season bullies yourself. Here are some security tips. Thrips are typically found on the upper and lower leaf surfaces and in folded leaves. They feed and reproduce on the leaves and buds of soybean seedlings. Search for crinkled, deformed and silver-colored leaves. Leaves may readily drop off when disturbed. When soybean plants are happy and growing vigorously, they will most likely laugh at the thrips and outgrow

their damage. However, consider standing up for your soybean seedlings and fending off thrips: if (i) 75% of the leaflets sampled are seriously injured, (ii) plants are weakened by drought or chemical injury, and (iii) numerous gangs of thrips are still hanging out at the playground. Although, soybean plants injured by thrips may not look like super models, thrips seldom justify insecticide treatment except in cases where there is severe loss of limbs (leaves) making plant death a possibility. Thrips will probably leave the playground for good by the final week of July and I say good- riddance.

Agronomy News - June 17, 2010 4

Central Overall, crops look good to excellent. The first cutting of forages is mostly complete, while pastures still are providing adequate grazing. Wheat has turned and looks good; corn and soybeans look good as well. Weed control in crop fields has been effective, although cleanup of perennial weeds is still ongoing. Rainfall over the past couple of weeks has been spotty, leaving some areas of in need of rain. Barley harvest is progressing. Wheat harvest is just underway with early reports of good test weights and quality. North East All corn and full season beans are planted and doing well. Barley harvest is just beginning; wheat is turning and harvest may begin a few days earlier than normal. After a wet May, and scattered showers in the first half of June, first cutting grass hay harvest is mostly complete, with some very good hay put up. In general, vegetable plantings are in the final stages, except for later planted snap beans.

Southern Barley harvest is well underway. Most folks are finishing barley now. Wheat harvest started last week and is proceeding well. Wheat quality and test weight seem excellent; yields are off about 15-20%. Double crop beans are being planted. Corn looks good overall, though many fields on sandier soils are showing drought stress. Corn is approaching tasseling. Rains over the last two days were much needed, and more will be required to continue rapid corn development. Soybeans look very good overall with the same story as corn --- rain is needed. Upper Eastern Shore Barley harvest is essentially finished with yields ranging between 50 -150 bu/acre. Wheat harvest is well underway with yields being 40-80 bu/acre with good quality and test weight ranging between 58-63. The entire area is very dry with corn and beans in the southern part of the region dying from drought. Bean planting has ceased waiting for better soil moisture. The one

benefit of drought is good quality and good yields from vegetables. Pea harvest is almost over with good yields reported. Sweet corn and tomato harvest is beginning in the southern part of the region. Hay yields have been good with some excellent hay made in the entire region. The northern part of the region will have much better 2nd cutting yields than the southern part of the region. Lower Eastern Shore Isolated rain showers in some areas have not produced adequate rainfall to alleviate dry conditions. As of this writing, many areas remain dry and corn is starting to show signs of stress. Full season soybean plantings are complete. Barley harvest is underway. Pasture conditions are fair to poor.

Poultry Farm Management Workshop on July 7th The University of Maryland Extension is conducting a one day workshop for new and existing poultry farmers on Delmarva focusing on poultry farm management. A variety of topics will be addressed including, site management and maintenance, mortality, manure handling,

litter management, windbreaks/vegetative environmental buffers, concentrated animal feeding operation regulations, nutrient management, comprehensive nutrient management plans, EPA inspections and emergency preparedness. The workshop will be held at Wicomico County Extension Office Meeting Room, 28647 Old Quantico Road, Salisbury, MD 21802 from 8:00 am to 3:30 pm.

Registration cost is $20 includes refreshments, lunch and materials. Register by June 30th by contacting Jeri Cook at 410-742-1178 or jcook2@umd.edu.

Upcoming Events

Did You Know

U.S. agricultural exports alone generate more than $100 billion annually in business activity throughout the U.S. economy and provide jobs for nearly 1 million workers.

Crop Reports

Agronomy News - June 17, 2010 5

This edition of Agronomy News is brought to you by: University of Maryland Extension Field Faculty: Ben Beale, Ag & Natural Resources Educator, St. Mary’s County Dave Martin, Ag & Natural Resources Educator, Baltimore County Doug Tregoning, Ag & Natural Resources Educator, Montgomery County Jim Lewis, Ag & Natural Resources Educator, Caroline County Richard Nottingham, Ag & Natural Resources Educator, Somerset County Sudeep Mathew, Ag & Natural Resources Educator, Dorchester County University of Maryland Extension Specialist: Dr. Cerruti R2 Hooks, Entomologist Dr. Robert Kratochvil, Agronomic Crop Production Dr. Ronald L. Ritter, Weed Control Specialist

Agronomy News is published by University of Maryland Extension, Ag & Natural Resources Profitability Impact Team. Sudeep Mathew, Editor Agronomy News subscriptions are free on the internet at: www.mdcrops.umd.edu To subscribe or more information: Agronomy News University of Maryland Extension 501 Court Lane, Room 208 Cambridge, MD 21613 410-228-8800 Email: rbarnhar@umd.edu

SIGN-UP TO RECEIVE “AGRONOMY NEWS” If you would like to receive this newsletter through email, please send an email to Rhonda Barnhart at rbarnhar@umd.edu. The subject line should be: Subscribe Agronomy News 2010. If you would like a hard copy please contact your local county extension office to sign-up for the mailing list. The list of local county offices can be found at www.extension.umd.edu.