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New FUN G I C I DE PRODUCTS By Amanda Scherer, Assistant Professor and Extension Plant Pathologist and Dave Han, Associate Professor and Extension Specialist, Turfgrass Management Auburn University and Alabama Cooperative Extension System
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Al ab ama Tu rf Tim es > >> Wint er 2024
urfgrass diseases can be a serious and costly problem in grasses used in golf courses, sports fields, and landscapes. Fungicide applications are a key component of the integrated pest management strategy for turfgrass disease prevention on golf courses and landscape management. Turfgrass management professionals have a wide range of fungicides to select from including contact vs. systemic fungicides, protectants vs. curatives, and single active ingredient products vs. combination products. Contact fungicides are protectants that provide a chemical barrier on turf leaf blades and stems to inhibit fungal growth. Contact fungicides require multiple applications on a regular schedule and adequate coverage to prevent disease. Classic examples include broad spectrum, multisite fungicides such as chlorothalonil (i.e., Syngenta’s Daconil Action®, Sipcam’s Echo 720®, etc.) and fluazinam (i.e., Syngenta’s Secure®). Contact fungicides tend to be cheaper, but since they do not enter a plant, they will be mowed off as a leaf grows. Also, new leaves that emerge after a spray will not be protected. Finally, contact fungicides cannot protect roots, so they are only useful against foliar diseases.
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In contrast, systemic fungicides penetrate plant tissue and are then moved within the plant. Since they are absorbed, they can protect roots if they are watered in well and absorbed by the roots. This is important: very few fungicides can move down from the leaves to the root system. So, to combat a root disease, fungicides must be watered in to ensure they get past the thatch and into the soil, where roots can pick them up. Although systemic fungicides have specific modes of action, they have both curative and protective properties that provide extended residual activity. Thus, systemic fungicides do not need to be applied as often as contact fungicides. Some examples include azoxystrobin (i.e., Syngenta’s Heritage®), mefentrifluconazole (i.e., BASF’s Maxtima®), and pydiflumetofen (i.e., Posterity®). Regardless, it is important to realize that not all fungicides are equally effective on all diseases. Labels should be referenced carefully to properly select the correct fungicide for a given disease. Below: Big Fairy Rings
