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5/23/2011 - 5/29/2011

Spring Control of Multiflora Rose

Bob Hartzler, Department of Agronomy

The last few years seem to have been favorable for the establishment and spread of multiflora rose (MFR) in pastures, CRP, timber and other areas that are not annually disturbed. Late spring is an excellent time for controlling MFR since herbicide applications at this time generally provide more consistent control than applications made later in the growing season after flowering.

Numerous herbicides will provide effective control of MFR when applied at the right time and manner. The following table provides information on some of these herbicides. Many of the active ingredients are off-patent and sold under different trade names.

Precautions should be taken to minimize off-target movement that may result in injury to desirable plants. Check labels for any restrictions that may pertain to use near water resources and for grazing of treated areas.

Mark Loux and others at The Ohio State University have prepared an excellent, in-depth bulletin titled Multiflora Rose Control that provides detailed information on multiflora rose and the effectiveness of chemical and other management tactics.


Bob Hartzler is a professor of agronomy with extension, teaching and research responsibilities.

Mini-bulk Container Recycling

Kristine Schaefer, Pest Management and the Environment

A new EPA Pesticide Container and Containment Rule that goes into effect Aug. 11, 2011 will change the requirements for repackaging bulk pesticides and will make many plastic pesticide mini-bulk containers unusable.  Applicators with these containers have the option to remove and recycle used mini-bulk containers through a program developed by ISU Extension Pest Management and the Environment Program, Iowa Department of Agriculture and Land Stewardship (IDALS), the Agribusiness Association of Iowa, and Iowa Institute for Cooperatives with contractor TRI-Rinse, Inc.

The 2011 recycling program is available for 85 to 350 gallon stand-alone or caged pesticide mini-bulk tanks. This is an excellent opportunity to help solve the problem of increasing stockpiles of damaged or non-compliant mini-bulk tanks. To participate in the program an inventory form should be filled out and mailed to TRI-Rinse, Inc. no later than July 15, 2011. This information is necessary to determine how many pesticide mini-bulk tanks are available for recycling, and which locations will be selected as collection sites in Iowa. The recycling fee is $15 per tank.

Tri-Rinse will provide instructions for preparation of the tanks.  Collections will begin in late summer or early fall. Additional details are included in this notice. Chemical companies are providing the major funding for their containers under their return programs.

Questions regarding the program can be directed to Mark Lohafer, IDALS, at 515-281-8506.


Kristine Schaefer is a program specialist in the Pesticide Management and the Environment program. She can be reached by email at or by phone at (515) 294-4286.

2011 Weed Science Field Day

By Mike Owen, Department of Agronomy

The Iowa State University Weed Science Field Day will be held on June 23 at the Curtiss Farm on South State Street in Ames, Iowa. The Curtiss Farm is easily accessible from Hwy 30;  exit at University Avenue, go south to the four-way stop, turn west to the next stop, turn north on South State Street and the farm is on the west. Follow the cinder road west through the farm to the registration tent.

Registration for the event will begin at 8 a.m. with brief remarks prior to the self-guided tour.  Registration will be $20 and cover refreshments and a field book that details all of the demonstrations and research at the Curtiss Farm location, as well as the other locations throughout Iowa. While the field day has historically been for the AgChem Industry, growers, seed dealers and agchem operators are welcome and will find much that will be of interest. If you have questions, contact Mike Owen at 515-294-5936 or


Micheal Owen is a professor of agronomy and weed science extension specialist with responsibilities in weed management and herbicide use. Owen can be reached by email at or by phone at (515) 294-5936.

CCA Credit Opportunity – June 15

By Jim Fawcett, ISU Extension field agronomist

Certified crop advisers (CCAs) can earn five hours of credit (three hours in soil and water management, 1.5 in pest management, and 0.5 in crop management) by attending a special CCA morning session, that proceeds the afternoon spring field day tour at the Southeast Iowa Research and Demonstration Farm near Crawfordsville on June 15.

The morning session will begin at 9 a.m., with a presentation by Greg Brenneman, ISU Extension agricultural engineer. Brenneman will cover recent tile drainage research results and 20 years of conservation tillage research. The morning session also will include a presentation on the biology and control of nematodes that feed on corn made by Greg Tylka, ISU Extension plant pathologist. The morning will conclude with a discussion in the field by Jeremy Singer, National Laboratory for Agriculture and the Environment agronomist, who will talk about everything you ever wanted to know about cover crops, but were afraid to ask.

The afternoon tour topics will include: Crop Season Review and Marketing Grain in Crazy Times by Kevin Van Dee, Farm Superintendent and Jim Jensen, ISU Extension farm management specialist; Corn Nematode Management, by Greg Tylka; Cover Crop Establishment and Management, by Jeremy Singer; and Making Fungicide Application Decisions, by Mark Carlton, ISU Extension field agronomist. Tours will begin at 1 p.m.

Registration for CCAs will begin at 8:30 a.m. The registration fee is $50, which includes lunch. Please pre-register by calling the Johnson County Extension Office at (319) 337-2145, or send an email note to Jim Fawcett at by June 13 to avoid a $20 late fee. The registration fee can be paid at the door. To reach the research farm go 1.75 miles south of Crawfordsville on Highway 218, then 2 miles east on G-62, then 0.75 mile north.


Jim Fawcett is an Iowa State University Extension field agronomist serving eastern Iowa. He can be reached at 319-337-2145 or by emailing

Estimating Quality of First Crop Alfalfa

Brian Lang, ISU Extension field agronomist


With the next dry weather window we will see a lot of first crop forage harvested.  Predictive Equations of Alfalfa Quality (PEAQ) monitoring shows alfalfa growth and development running about one week behind normal. Those that usually consider first crop harvest on May 25 need not be too concerned with not harvesting yet. Most of the alfalfa is barely into bud stage at this time. 


PEAQ provides an estimate of the quality, measured as Relative Feed Value (RFV), of a crop of first cutting alfalfa standing in the field. Typically, the RFV of first crop alfalfa will decline 3 – 5 points per day as the crop matures. Under the best conditions, 10 to 20 percent of the forage dry matter will be lost at harvest. This amounts to approximately 15 RFV points for haylage and 25 RFV points for hay. Therefore, to end up with 150 RFV alfalfa, which is the minimum quality recommended for high producing lactating dairy cows, you should harvest the crop when PEAQ measurements predict a RFV of 165 to 175 for the standing forage. PEAQ reporting (click on “All Above Counties” on the lower right) shows less than half of the fields being monitored are ready for harvest (176 RFV or less) and the others running 196 RFV or more are still one week or more away from harvest. 


Farmers are welcome to follow the progress of these reports, but they are encouraged to use PEAQ in their own fields to best determine first crop harvest of alfalfa. Refer to the PEAQ fact sheet for guidelines on estimating the RFV of your alfalfa fields.  




Brian Lang is an Iowa State University Extension field agronomist serving northeastern Iowa. He can be reached at 563-382-2949 or

Japanese Beetle Distribution in 2010

By Forrest W. Nutter, Jr. and Andrew Gougherty, Department of Plant Pathology; Donald Lewis, Department of Entomology

The Japanese beetle [Popillia japonica (Newman)] first detected in Iowa in 1994, was detected for the first time in six additional counties in Iowa in 2010. Reports from all six counties (Audubon, Carroll, Cherokee, Hamilton, Harrison and Ida) were obtained as part of a Bean pod mottle virus/bean leaf beetle survey funded by the Iowa Soybean Association. 

Although less efficient than bean leaf beetle in acquiring and transmitting Bean pod mottle virus, in 2010, Japanese beetles were more abundant than bean leaf beetles in soybean sweep net samples from many Iowa counties. The 2010 reports confirm the presence of Japanese beetles in 52 of 99 counties in Iowa. Samples for the newly reported counties were provided by Iowa State University Extension Field Agronomists Joel DeJong, Mark Licht and Clarke McGrath; Harrison County Extension Program Director Rich Pope; and John Eveland, retired Humboldt County Extension Director.

Figure 1. Updated map showing confirmed distribution of Japanese beetles in Iowa counties in 2010. The 2009 distribution map was published in Horticulture and Home Pest News.

The Bean pod mottle virus/bean leaf beetle survey will be conducted again in 2011. If you find Japanese beetles in a county not marked on the map, please let us know by sending specimens or digital images including capture location and date. Mail to: Plant & Insect Diagnostic Clinic, 327 Bessey Hall, ISU, Ames IA 50011. Email to: .


Forrest W. Nutter, Jr. is a professor in the Department of Plant Pathology working on disease risk models for improved disease management. Andrew Gougherty is a research assistant in the Plant Disease Epidemiology Laboratory in the Department of Plant Pathology. Donald Lewis is extension urban entomologist and professor in the Department of Entomology.

Spring is Time to Evaluate Field Grass Waterways

By Mahdi Al-Kaisi, Department of Agronomy

With most of our corn and soybean planting completed or on its way to completion, it’s time to think about the soil. Fields at this time are most vulnerable to soil erosion because of degraded crop residue cover during soil preparation by tillage, and the crop canopy is not yet present to protect the soil. Even fields with a relatively flat to moderate slope have shown some significant erosion during the past week’s rain events. This is especially apparent in areas of the field where waterways can be very valuable in reducing soil erosion. It is time well spent to evaluate and take an inventory of your field for proper grass waterways placement and for repairing the existing grass waterways and buffer strips.

Springtime rain can come hard and fast as we experienced last week, causing substantial soil erosion. Field observations at this time can provide some insight on how to manage your field and protect your soil and water quality. The soil profiles in most of Iowa are now filled to capacity with water.  Therefore, the amount of rain we receive can exceed the soil storage capacity, especially since plant water use is very low at this time of the year. Maintenance of grass waterways is essential to maximize the benefits and effectiveness of such practices in reducing soil erosion.

These conservation practices (i.e., buffer-strips, grass waterways, etc.) are critical for protecting soil quality and sustaining crop productivity. Also, the relationship between water quality and soil erosion cannot be over-emphasized; soil erosion and loss of top soil can have a huge impact on yield. Therefore, implementation of conservation practices can be significant in controlling soil erosion, and improving soil and water quality.

Areas in the field such as this indicate a need for a grass waterway.



Mahdi Al-Kaisi is an associate professor in agronomy with research and extension responsibilities in soil management and environmental soil science. He can be reached at or (515) 294-8304.

Soybean Field Guide Revised and Updated

Daren Mueller, Department of Plant Pathology

Iowa State University and the Iowa Soybean Association recently released a collaborative publication, the Soybean Field Guide, CSI 0010,  which is a revision and update of the popular Soybean Disease and Pest Management Field Guide.

The pocket-sized guide is a durable and weather-resistant publication and has been expanded from 52 to 68 pages. It now features five sections on production, integrated pest management (IPM), diseases, insects and disorders. It includes several additional insects that impact soybean production, as well as disorders like hail damage and nutrient problems.

Soybean diseases and insects are the farmers’ number one concern in profitable soybean production. This field guide has been designed to enable farmers’ easy identification of problem yield robbers, as well as providing valuable production information. Funding for printing and distribution of the guide was provided by the Iowa soybean checkoff and ISU Extension.

Printed copies of the Soybean Field Guide can be ordered from the ISU Extension Online Store at or by calling 515-294-5247; or by contacting the Iowa Soybean Association at 800-383-1423. The guide can also be viewed online at

Daren Mueller is an extension specialist with responsibilities in the Corn and Soybean Initiative and ISU's IPM program. Mueller can be reached at (515) 460-8000 or by email at

Early Preplant and Preemergence Applications Not Season Long Control

By Micheal Owen, Department of Agronomy

A few Iowa growers were able to get herbicides applied prior to planting and emergence of the crop but now some are expressing concerns that the herbicidal activity has diminished. In many instances, the rate of herbicide application was not the full labeled rate. Thus, the fact that weeds are beginning to emerge through the herbicide treatments should be expected. Many weeds emerge opportunistically and as the amount of herbicide in soil diminishes due to degradation, new weeds are likely to emerge despite the earlier herbicide application. Remembering some important weed management expectations and perspectives will help growers get the highest potential crop yield.

First, the goal of early preplant (EPP) and preemergence (PRE) applications is to control early weed growth. Generally, this goal was successful and the crop was provided a (relatively) weed free environment early. However, regardless of what some advertising suggests, no herbicide treatment will provide full season control consistently and more importantly, meet grower expectations. It is unreasonable from an environmental, ecological and economic perspective to expect otherwise. Herbicides begin to degrade the moment they are applied.  An appropriate expectation for a soil-applied herbicide treatment would be six to eight weeks of effective control. If rates of application were reduced, expect less weed control. As indicated, the goal of effective early season weed control was generally met. 

Second, considering that early season weed competition is most costly to crop yield potential, there was significant economic value to the EPP and PRE treatments even though control may be declining.  Now, the next round of weed management treatments must be established. Appropriate mechanical and/or POST herbicides should be timed just as carefully as the EPP/PRE, perhaps even more carefully given the effects of weed size and crop stage of development. Generally, early application timing on small weeds and crops is better than late and large. Scouting is an important weed management strategy.

Third, the mechanisms of herbicide action (MOAs) of the second round of weed control must be reviewed and provide diversity so as not to repeat the same MOAs as the EPP and PRE herbicide treatments. Refer to the herbicide label and the herbicide family number that is listed, or if a particular product label does not have the MOA number listed; refer to 2011 Herbicide Guide for Iowa corn and Soybean Production, WC- 94. It is critically important that MOAs be diversified as much as possible in order to provide stewardship and mitigate the evolution of herbicide-resistant weed populations. Repeated applications of the same MOAs will inevitably result in herbicide-resistant weeds; do as much as possible to diversify weed management tactics as possible. 


Micheal Owen is a professor of agronomy and weed science extension specialist with responsibilities in weed management and herbicide use. Owen can be reached by email at or by phone at (515) 294-5936.

This article was published originally on 5/30/2011 The information contained within the article may or may not be up to date depending on when you are accessing the information.

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