The most important weed management tasks are done before planting. Good site preparation includes scouting for perennial weeds and controlling the difficult species such as trumpet creeper, multi flora rose, mugwort, Florida artichoke, kudzu, and field bindweed before planting. Manual or mechanical control of perennial weeds can be difficult and costly once the field is planted. Controlling perennial weeds requires killing the root system, since most perennial weeds will regrow if only the top is destroyed. There are three options for controlling perennial weeds: cultivation, fumigation, or systemic postemergence herbicides (Roundup or Finale). While cultivation can be effective against perennial weeds, multiple cultivations over a period of several months are often required to control the root systems. Fumigation is discussed in an earlier section. Systemic postemer-gence herbicides such as glyphosate (Roundup and many other trade names) and glufosinate (Finale) will control many perennial weeds, but timing of the application is critical to ensure satisfactory perennial weed control. Rates and timing of Roundup application to control selected perennial weeds are shown in Table 2.
Planting cover crops, plowing in fall, and allowing the land to remain fallow can help to reduce some weed and insect problems. The intense shading, mowing, and competition created in a green manure or cover crop program will greatly reduce, if not eliminate, certain weed problems. Fall plowing exposes roots and tubers to the freeze-thaw cycles of a North Carolina winter.
Growing each species of nursery crop in separate blocks allows for more options in weed control. For example, separate hemlocks from other conifers because hemlocks are sensitive to some preemergent grass herbicides. Similarly, blue green junipers are sensitive to some postemergent herbicides. Another management consideration is herbicide carryover from one season to another. When planning new fields, obtain the herbicide history because some herbicides remain in the soils and cause problems for new crops.
Pest Management Irrigation