Effect of Mowing Height in Turfgrass Systems on Pest Incidence
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Date
2009-06-24
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Abstract
Field experiments were conducted to 1) determine if discrepancies occur between multiple methods for estimating large crabgrass cover to determine the most precise, accurate, and efficient method, 2) determine the effect of mowing height on large crabgrass incidence in common bermudagrass, 3) determine the effect of mowing height on large crabgrass and brown patch incidence in tall fescue, and 4) determine the effect of mowing height on common bermudagrass encroachment in tall fescue. All experiments were conducted at two locations in North Carolina. Mowing heights for experiments included 2.5, 5.1, 7.6, and 10.2 cm for tall fescue and 1.3, 2.5, 3.8, and 5.1 cm for common bermudagrass. Evaluation methods for estimating large crabgrass cover consisted of Visual Ratings (VR), Line Intersect Analysis (LIA), and Digital Image Analysis (DIA). All methods were compared to VR, the standard and accepted method of data collection. It was found in two separate field experiments that there were no differences among the three rating methods. No effect of mowing height on large crabgrass incidence in common bermudagrass was found at 5 months after initiation (MAI).
Increasing tall fescue mowing heights resulted in reduced large crabgrass incidence and increased brown patch incidence. The presence of brown patch did not affect large crabgrass incidence. As mowing height increased, percent crabgrass cover at 6 MAI decreased. With increasing mowing heights percent brown patch cover increased in tall fescue.
Immediately following installation of common bermudagrass in tall fescue, mowing height treatments of 2.5, 5.1, 7.6, and 10.2 cm were initiated. Research determined that with increasing mowing heights in tall fescue, the percent of common bermudagrass cover was significantly reduced, especially after one year of growth.
These results show that VR may be more widely accepted in weed control studies in turfgrass systems. The mowing height of common bermudagrass will not suppress large crabgrass. A mowing height of 7.6 cm in tall fescue can reduce large crabgrass populations, decreasing dependence on pre-emergence herbicides, and keeping brown patch infestations below a common threshold of 5% brown patch cover. To prevent spread of common bermudagrass in tall fescue after contamination a mowing height of 7.6 or 10.2 cm is recommended.
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rating methods, brown patch cover, large crabgrass cover, subjective data, bermudagrass cover, mowing height, contamination
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Degree
MS
Discipline
Crop Science
