Managed sod row middles have many advantages, and have been adopted by many tree fruit growers. They provide a firm drive path for spring spraying of insecticides and fungicides, prevent or reduce soil erosion, and improve soil tilth by increasing soil organic matter. Broadleaf weeds in the sod should be controlled. Weeds are alternate hosts for insects diseases, and nematodes, and weeds in bloom can attract natural pollinators into the orchard throughout the spring and summer. Many insecticides warn against use when bloom is present in the orchard.Good sod management practices will help suppress weeds, including white clover, which can be is difficult to control. Use herbicides with good management practices to maintain the sod free of weeds. Manage fertilizer applications to favor grass rather than the clover. Nitrogen fertilizer stimulates grass growth, and phosphorus and potassium stimulate clover growth in a mixed grass and legume sod. Do not apply fertilizer containing phosphorous or potassium to sod if clover control is a problem. Rather, apply fertilizer for tree growth in the vegetation free strip. Mowing height also influences the composition of a mixed grass and clover sod. Close mowing favors the clover. Taller sod will favor the grass. Mow no closer than four inches if clover control is a problem in the sod.
Weed control in the sod should be completed in early spring or delayed until fall. Weeds are most susceptible to 2,4-D when they are growing vigorously, not under stress, and before flower buds appear. The herbicide must be applied BEFORE dandelions begin to bloom in April for maximum effectiveness. Apply Prowl H20 at 1 to 1.5 quarts per acre to control summer annual grasses that can weaken the sod, including crabgrass species, foxtail species, and others.
WARNING: Use only 2,4-D formulation(s) labeled for use in orchards. Lower cost 2,4-D formulations are available but may be more likely to drift, may not contain a “low drift” agent in the formulation, are not labeled, and should not be used! BEWARE of herbicide drift! Grapes, many flowers, and vegetables are extremely sensitive to 2,4-D. Injury may occur in adjacent fields if sprayed when unfavorable conditions prevail.
Certain weeds, including clover species, wild onion and garlic can be suppressed or controlled with 2,4-D, but good results require additional effort. The leaves of clover are densely covered by fine hairs and wild onion leaves are waxy and vertical. Both weeds retain spray poorly. Add nonionic surfactant to increase wetting and spray retention to improve control. Add the surfactant in units of 1 quart per 100 gallons of spray solution. Check for improved wetting after adding each quart of surfactant. The amount of surfactant needed will depend on the characteristics of the water used. Use the amount needed to improve wetting. Too much or too little surfactant will reduce control. Splitting the application by applying half the 2,4-D rate twice, about seven to fourteen days apart, will further improve the suppression or control of clover and wild onion. Use 2,4-D in conjunction with good fertilization and mowing practices to suppress clover on sites where the weed is well adapted.
In apples and all stone fruits, add 3 to 4 fluid ounces of Stinger 3A per acre to 2,4-D to dramatically improve the control of white clover. Consult the Commercial Production Recommendations for rates and additional information.