To spray or not to spray, part two

A recap of last week's check list for successful herbicide applications include assessing current weather and environmental conditions, the time of year, selecting the proper herbicide, and considering alternatives to chemical herbicides. Is this really the best time of year for an herbicide application? Goldenrod and tall ironweed are blooming and I have received several calls asking for herbicide recommendations. Those weeds are best controlled in late spring through early summer when they are actively growing. Herbicides applied now will not deliver much bang for the buck. Good grazing practices including not overgrazing and maintaining proper pasture fertility levels go a long way towards controlling most pasture weeds. Clipping before and during flowering exhausts the root system and prevents new plants from becoming established from seed next year, but if a spray program is necessary tackle those weeds next year. This can be a good time of year to spray woody shrubs and brambles including wild blackberry, Japanese barberry, and multiflora rose – depending on the herbicide product. What product should you apply? It depends. As an example, Pasturegard HL offers excellent control of brambles after fruit drop in late summer/early fall, but is more effective against multiflora rose earlier in the season. Apply Remedy Ultra 4EC in spring for both. What about 2, 4-D and Roundup? 2,4-D does not offer consistent control of brambles, killing only the top growth. Roundup or glyphosate is nonselective and will kill pasture grass. Do not use it in fencerows. What happens when you kill grass – you get more weeds. Grass is your best defense against weeds – don't kill it. Before purchasing herbicides, check out the UT Weed Control manual, published annually with the most recent data on common herbicides and their use in crop, pasture, and hayfield applications. Available online or for viewing at the UT/TSU Extension Office, it's well worth a look before spending money. When selecting herbicides, take time to read and understand the label. Familiarize yourself with the ingredients, weeds controlled, precautionary statements, application directions, product rates per gallon and recommended adjuvants. Adjuvants? Adjuvants increase herbicide absorption. Remember the cuticle from last week? An adjuvant such as non-ionic surfactant, aka spreader-sticker helps the herbicide break through the cuticle/waxy leaf surface. Always add the recommended adjuvant/surfactant. Surfactants are cheap and increase herbicide effectiveness. Do not use dish soap as a surfactant substitute. Dish soap contains both nonionic and anionic surfactants, and when combined with an herbicide can result in crop injury, reduced efficacy, and may leave a residue on leaf surfaces. Most importantly they are not labeled for agricultural or crop use. &emsp;&emsp;