16 articles tagged "Weed Management".

Waterhemp is prevalent in the Midwest and the Great Plain States. It became a significant agricultural weed in 1990s. Before then it was present in crop fields, but it is presumed that it rarely reached economic infestations. It became a problem in Indiana by 1998. Waterhemp is best adapted where less aggressive tillage is practiced. The adoption of conservation tillage might have aided in its widespread establishment. Also, the use of herbicides in the late 1980s coincided with the spread of waterhemp, and it quickly became resistant to Group 2 herbicides (ALS-inhibitors). Today waterhemp populations have been documented to also have resistance to Groups 5 (Photosystem II-inhibitors), 9 (glyphosate), 14 (PPO-inhibitors) and 27 (HPPD-inhibitors or “bleachers”). Identification: At the seedling stage, it can be difficult to distinguish waterhemp from other pigweeds. Cotyledons are egg- to ovate-shaped (Figure 1). When plants are larger, waterhemp can be differentiated because it has no[Read More…]


Dual Magnum® is registered for use in numerous row crops and specialty crops in the state of Indiana. While some vegetable crops (beans, peas, potatoes, pumpkins, rhubarb, and tomatoes) appear on the specimen or national label (Section 3 label), most do not. Numerous specialty crops that do not appear on the specimen label are included in the 24(c) special local need label. But finding the 24(c) label, which was recently updated in 2019, can be difficult. The new 24(c) label is available on the National Pesticide Information Retrieval System web site: http://npirspublic.ceris.purdue.edu/state/state_menu.aspx?state=IN. To find it, type “SLN IN” and “130003” in the first two boxes for “EPA Registration Number” and click the search button. The product report will show “DUAL MAGNUM – TRANSPLANTED BELL PEPPERS.” Click on the ALLSTAR symbol. On the page that opens, click on the Company Label ID number “IN0816048DA0319.” This will open a pdf of the label. The[Read More…]


Figure 2. Young giant ragweed seedling with three-lobed leaves. Photo by Stephen Meyers.

Scientific name:  Ambrosia trifida Giant ragweed is a weed member of the sunflower family (Asteraceae) and native to the United States. It is extremely competitive and difficult to control in broadleaf crops. It emerges as early as March and continues to germinate through spring and early summer. Controlling giant ragweed during summer is not only important for crops but also for human health because giant ragweed pollen can be an allergen for some people. Identification: Seed leaves of giant ragweed are large and oblong. The first pair of true leaves are often unlobed and lance shaped (Figure 1). Subsequent leaves are large and three- or five-lobed with serrated margins (Figures 2 and 3). Growth habit: Erect summer annual, reaching 3 to 16 ft (Figure 4). Grows at approximately twice the rate of most annual weeds, and is likely to be 8 to 12 inches tall when other weeds are 3[Read More…]


Figure 1. Overwintered Canada thistle shoots emerge in April in central Indiana.

Spring is here and with it comes the emergence of weeds- especially problematic perennials like Canada thistle (Figure 1). Below is some information about Canada thistle and methods to manage it. Keep in mind two things: 1) many of these strategies will work for other perennial weeds, and 2) management of perennial weeds often requires persistence and an integrated approach. Scientific name: Cirsium arvense (L.) Scop. Legal status: Canada thistle is considered a noxious weed in 46 states including Indiana. It is a non-native invasive species from Europe, and landowners with Canada thistle on their property are obligated to take measures to control it. Growth habit: Deep-rooted and colony-forming perennial. Plants form a low-growing rosette in the spring prior to bolting in mid-to-late May. Reproduction: By seeds carried up to 1/2 mile by wind and through adventitious shoots that develop from root buds. Control: Often multiple types of control measures[Read More…]


In the October 2019 issue of the Vegetable Crops Hotline, I referenced the new regulatory changes to herbicides containing the active ingredient paraquat. One of the new requirements is for closed system packaging. To quote the Environmental Protection Agency (EPA): “New closed-system packaging (is) designed to prevent transfer or removal of the pesticide except directly into proper application equipment. This will prevent spills, mixing or pouring the pesticide into other containers or other actions that could lead to paraquat exposure.” Earlier this month I had a chance to see one of the ways chemical companies are complying with the new regulation. At the Weed Science Society of American Annual Meeting, Syngenta presented their closed packaging and transfer system. It contains a closed system cap that cannot be removed or opened by hand (Figures 1 and 2). In order to remove herbicide from the container, the cap must be connected to an[Read More…]


As the production season winds down there are two weed-related news items that producers should be aware of: New Requirements for Users of Paraquat Herbicide.  Paraquat dichloride is the active ingredient in products such as Gramoxone®, Devour®, Cyclone®, and Quik-Quat®. Earlier this year the Environmental Protection Agency (EPA) announced the following changes to paraquat requirements: Additional labeling requirements and the distribution of supplemental warning materials at the point-of-purchase are now required and highlight the toxicity and risks associated with paraquat products. Paraquat use is now restricted to certified applicators only. No longer can an uncertified handler use paraquat, even under the direct supervision of a certified applicator. Specialized, approved paraquat training is now required for anyone who will mix, load, apply, or handle paraquat. New, closed-system packaging will be used to prevent the transfer or removal of paraquat into unapproved containers or equipment. These changes were sparked by unnecessary deaths[Read More…]


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Dual Magnum® has had a special local needs (24C) label in Indiana for use on transplanted bell peppers and other vegetables for a number of years. Last week the label was amended to include additional small fruit and vegetable crops, including asparagus. The new 24C label is available on the National Pesticide Information Retrieval System web site: http://npirspublic.ceris.purdue.edu/state/state_menu.aspx?state=IN. To find it, type “SLN IN” and “130003” in the first two boxes for “EPA Registration Number” and click the search button. The product report will show  “DUAL MAGNUM – TRANSPLANTED BELL PEPPERS.” Click on the ALLSTAR symbol. On the page that opens, click on the Company Label ID number “IN0816048DA0319.” This will open a pdf of the label. If you decide to use the product, carefully read and follow the label instructions.


Three videos on in-row weeding tools (Finger weeder, Torsion weeder, Tine harrow) were developed at the Michigan State University Department of Horticulture. Each video is 20 minutes: introduces the tool, how it works, different models, show adjusting the tool in the field, and a short interview with a farmer who uses the tool. These videos can be accessed at the MSU Mechanical Weed Control Channel https://www.youtube.com/channel/UCH-k889oYbUaEznvgiDtrOQ


This article provides more detailed information about this herbicide. How does Chateau® herbicide work Chateau® is a group 14 mode-of-action herbicide. Compounds in this group are most active on broadleaf weeds. Before Chateau® became available,  no other preemergence herbicide with the same mode of action was labeled for use in watermelons and cantaloupes. The active ingredient of Chateau® herbicide, flumioxazin, controls susceptible weeds by inhibiting propoporphyrinogen oxidase (PPO), an enzyme that controls chlorophyll synthesis. Because of chlorophyll production inhibition, a chain reaction occurs within the plant that causes cell membrane disruption. Chateau® herbicide can assist in the postemergence control of emerged weeds. It is taken up by roots, stems, or leaves of young plants. It kills weeds through direct contact. There is usually little or no translocation of the herbicide within plants. Foliage necrosis can be observed after 4 to 6 hours of sunlight following the herbicide application. Susceptible plants[Read More…]


Chateau SW® herbicide now has a 24(c) special local needs label for cucurbits. This product is produced by Valent, but the label is held by the Indiana Vegetable Growers Association (IVGA).  To obtain a label, one must be a member of the IVGA, pay an annual $100 processing fee, read and understand the ‘conditions for use’ and have the appropriate forms signed and notarized. One cannot use Chateau SW® without completing these forms and obtaining a label. This process must be repeated every year. Chateau® can only be used in row middles between raised plastic mulch beds that are 4 inches higher than the treated row middle. The mulched bed must be at least 24 inches wide. The application must be directed between rows with a shielded sprayer. Chateau® cannot be applied post-transplant. Do not apply more than 4 oz. of Chateau® per acre at a broadcast rate during a single application.[Read More…]


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