Wisconsin Crop Manager newsletter

Author:	WCM Staff	Created:	4/21/2006 11:13 AM
Weed woes

Japanese hops, a new weed species to be aware of in Wisconsin

By WCM Staff on 8/21/2008 3:15 PM

Last week we received two unknown weed samples for identification, one from a homeowner, the other from a field in southwest Wisconsin. The homeowner version was common hops, a native species or non-native variety of this species used for hop production for beer (Humulus lupulus). The other species in the agricultural field was Japanese hops (Humulus japonicus) a new non native invasive plant spreading in Wisconsin.

Public Hearing Scheduled for proposed invasive species rule for Wisconsin

By WCM Staff on 7/24/2008 12:27 PM

The Wisconsin Department of Natural Resources is developing rules to address invasive species in Wisconsin, including invasive terrestrial and aquatic plants. The proposed rules will establish a classification and regulatory system for invasive species.

Giant Ragweed and Nightcrawlers

By WCM Staff on 7/16/2008 2:11 PM

This summary of research that has been conducted on giant ragweed and nightcrawlers explains the reason that giant ragweed is so persistent.

Warnings on Following Pesticide Labels

By WCM Staff on 7/9/2008 1:14 PM

Weather extremes can place enormous pressure on growers and applicators to use pesticides in manners that violate label directions. This year’s weather has certainly been a case in point. With the flooding in Wisconsin, many questions have been asked about the potential to replant different crops after herbicides had been applied to corn or other crops.

Soybean Weed Management: A Mid-Season View

By WCM Staff on 7/2/2008 1:35 PM

Yesterday at the UW Pest Management Field Day, the benefits of preemergence herbicides in managing early-season weed competition and herbicide application timing in soybean were clearly visible. In two field trials, we had applied an array of preemergence broadleaf herbicides, which will be followed by postemergence applications of glyphosate. The intent of these preemergence herbicides was to provide initial suppression of broadleaf weeds so that glyphosate applications could be delayed.

Balancing Herbicide Drift vs Spray Timing

By WCM Staff on 6/18/2008 1:46 PM

Three recent events trigger this article. First, a call from a landowner with significant concerns after watching a herbicide application with winds alleged at 20 mph blowing towards their berry crop. Second, yesterday’s wind that was gusting well over 20 mph and preventing herbicide applications at a time when we need to spray our trials just like many custom applicators and growers who need to spray corn fields. Third, a call asking about the risk of dew affecting glyphosate performance if spraying in early mornings to avoid the wind.

Herbicides, Rain, and Replanting

By WCM Staff on 6/12/2008 12:25 PM

The heavy rains that many fields received will raise a few key questions regarding herbicide performance and replant considerations. A major question with preemergence corn and soybean herbicides is if the heavy rains leached the herbicide out of the upper soil profile.

Volunteer RR Corn: A New Soybean Weed?

By WCM Staff on 6/4/2008 2:42 PM

While volunteer corn has been a “weed” in soybean fields ever since corn fields have been rotated to soybeans, we have not thought much about volunteer corn with Roundup Ready soybeans. Prior to significant adoption of glyphosate-resistant (e.g. Roundup Ready) corn, any volunteer corn would easily be controlled in soybeans when glyphosate was applied.

Limits for Postemergence Corn Herbicides

By WCM Staff on 6/4/2008 2:31 PM

Despite the fact that corn has struggled with this spring’s cold weather, it eventually will start growing once we get some heat. As corn and weeds start to grow more rapidly, it’s important to keep track of the right timing to apply herbicides if using a postemergence herbicide.

Weed Quiz: Weeds in Corn

By WCM Staff on 5/29/2008 8:56 AM

What is the best timing to control weeds with a herbicide in corn? Does your answer change if question #1 is changed to “What is the best timing to manage weeds in corn?”

Prepare for Weeds in Corn

By WCM Staff on 5/28/2008 2:05 PM

Successful preemergence corn herbicide programs require two key components. First, the programs need dry weather (with limited wind) in order to have the preemergence herbicides applied. Second, the programs generally need 0.5 to 1 inch of rainfall to activate the herbicide after the application, which moves the herbicide from the soil surface into the zone where weeds are germinating.

Cleaning Herbicides from Sprayers

By WCM Staff on 5/21/2008 2:53 PM

The potential for crop injury from herbicide contaminated sprayers is generally greatest with postemergence applications. Without proper clean out of sprayers, herbicide residues from one spray load can contaminate the next load and injury a sensitive crop. This is logical because the spray is making direct contact with the crops and is not being diluted with soil as with preemergence applications. Also, postemergence herbicides obviously have foliar activity, which may not be the case with all of the preemergence herbicides.

Herbicides Kill Weeds – Why not the Crop?

By WCM Staff on 5/15/2008 1:25 PM

Why is it that crops are not harmed by herbicides? The simple explanation is that some plants are able to metabolize (or detoxify) the herbicide into non-toxic chemicals before they damage the plant. However, before the discussion continues about metabolism, a quick review about herbicide mode of action is justified.

Managing invasive plants in fields enrolled in the CRP in Wisconsin

By WCM Staff on 5/8/2008 4:46 PM

Due to the uniqueness in managing CRP fields, we have developed specific factsheets to help in developing management plans for these listed species in CRP fields (see links).