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Landscape and Turf Maintenance By Alec Kowalewski, Aaron Hathaway, Alfredo Martinez-Espinoza and Kris Braman Integrated Pest Management S ustaining high-quality turfgrass requires a well integrated pest management program. Inte- grated pest management will not only provide effective pest prevention and control, but it will also re- duce maintenance costs and management impacts on the surrounding environment. Mowing Increasing your mowing height and fre- quency are important aspects when design- ing a well integrated pest management program. Increasing your mowing height will minimize the encroachment of invasive weeds such as crabgrass, dandelion and white clover. Increasing mowing heights will also increase rooting depth and, subse- quently, increase turfgrass tolerance to stresses such as drought, insects and pathogens. Increase mowing heights during the summer months, when the potential for heat stress is high, and then gradually de- crease the height prior to fall. Some general seasonal mowing height recommendations for Kentucky bluegrass are 3 inches during the summer, gradually reduced to 1.5 inches before fall. Hybrid bermudagrass on the other hand is often maintained at heights as low as 0.05 inches on athletic fields. Increased mowing frequencies have also been shown to improve turfgrass health and vigor. For instance, simply increasing mowing frequency from once to twice per week has been shown to improve cover, surface strength and wear tolerance. Fertilization When developing a fertilization plan, consider the environmental conditions in which their turfgrass thrives. Fertilize Ken- tucky bluegrass at increased rates (1.0-1.5 lbs N/1,000 ft2/month) in the spring and autumn, and decreased rates (0.5-1.0 lbs N/1,000 ft2/month) throughout the sum- mer, totaling 3-5 lbs N/1,000 ft2/year. Bermudagrass, because it is a warm season turf, will require relatively high application www.landscapeirrigation.com Foliar symptoms (left) and dark brown to black roots and rhizomes resulting from spring dead spot of bermudagrass (right). Photos courtesy of Alfredo Martinez. Circular brown patches (left) and necrotic leaves (right) resulting for brown patch infestations. Photos courtesy of Lee Burpee and Alfredo Martinez. rates (1.0-1.5 lbs N/1,000 ft2/month) during the summer and relatively light ap- plication rates (0.5-1.0 lbs N/1,000 ft2/month) in the spring and fall, totaling 5-6 lbs N/1,000 ft2/year. Weeds that indicate nutrient deficien- cies include white clover and common dandelion. Dollar spot and rust thrive in nitrogen-deficient turfgrass, therefore, a light application of a quick-release fertil- izer high in nitrogen, such as urea (46-0-0) or ammonium nitrate (34-0-0), is often prescribed. However, brown patch and Pythium blight thrive when high nitrogen levels are combined with poor drainage, humidity and heat stress. A fertilizer appli- cation during these circumstances would only increase disease severity. It is advantageous to select complete fertilizers containing relatively high con- centrations of nitrogen (N), low concen- trations of phosphors (P) and moderate levels of potassium (K), a ratio of approxi- mately 4N-1P-2K. Apply controlled- release fertilizers in the summer months when microbial activity and the potential for fertilizer burn is high and apply quick- release fertilizers high in nitrogen (applied at a maximum of 0.5 lbs N/1,000 ft2/ap- plication) in the spring and/or fall. Irrigation Environmental conditions and turfgrass species are often intertwined factors when making irrigation adjustments throughout the seasons. Cool season turfgrass will likely require more frequent irrigation during periods of drought stress when root necrosis occurs. It is important to note that diseases like Pythium blight and brown patch thrive in poorly drained, over- irrigated soils, while dollar spot thrives on Landscape and Irrigation 21