Benefits Associated with a
Fall Preemergence Herbicide Application
A fall preemergence (PRE) herbicide application is something all growers should consider. The immediate benefit of a fall PRE herbicide is residual winter annual weed control. Winter annual weeds are not a competition concern through winter, but are competitive in the spring when trees break dormancy. Controlling winter annual weeds is part of an integrated management approach for other orchard pests like cat facing insects and rodents. Elimination of winter annual weeds, which are hosts for insects, from the orchard floor reduces cat facing insect populations. Rodents find orchards infested with winter annual weeds attractive. Ground cover provided by weeds creates a desirable rodent habitat.
The radiant heat benefit associated with bare soil under trees is often over looked. Eliminating winter annual weeds allows the soil surface to maximize heat absorption from the sun. During frost freeze events in the spring, heat from the soil is released over night. The released heat elevates orchard temperatures. The increase in temperature may only be a couple of degrees, however fruit loss associated with freeze damage can be minimize with small increases in temperature.
Fall PRE herbicides aid spring and summer weed control by delaying spring application time. A fall PRE herbicide spray can delay the spring application for 6 to 8 weeks. The result is a 6 to 8 week extension of preemergence weed control into the summer.