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NC State Extension

The Foundation of Pest Control — Cultural Controls

Why Cultural Practices are Important

clover-225Pest control in Fraser fir Christmas trees starts with site selection and ends only when all the trees are harvested from a block. The foundation of IPM is good cultural practices that prevent pests from developing and keep trees growing. Preventing pest problems is a much more cost effective, environmentally friendly, and efficient means of pest control than trying to treat a problem with a pesticide. On this site, many insecticides and miticides are recommended for various pests. These products — some of which are OMRI registered for organic production — are only one tool in the pest control toolbox. The use of pesticides cannot correct a situation where good cultural practices are not being followed. That’s because the pests will just keep coming back since the field site and production practices are suited for them. Therefore, good cultural practices are the foundation for pest control and will result in the most efficient use of pesticides.

Most Important Cultural Practices in Fraser Fir

The following cultural practices will create an environment that will favor natural predators and not pests. Information about the pertinent cultural practices for each pest is described in the individual pest control focus pages (see: Control Based on Highest Priority Pest). Important cultural practices include:

  • Site selection — Site selection is important for more than just Phytophthora root rot control. The site on which trees are located will determine rainfall, humidity, and temperature which affect both pest and predator development. Site selection can also impact what pests are prevalent. A windy ridge or south facing slope will have more problems with spider mites for instance. Elevation is a key determining factor in pest problem. A grower might not have a lot of control over where to grow Christmas trees, but knowledge about a difficult site can aid in scouting and pesticide selection.
  • Avoid interplanting — Interplanting young trees with older trees produces a mixed age stand that is difficult to manage for pests. Though not all growers can avoid interplanting because of land constraints, it should be avoided whenever possible.
  • Ground covers — Managing ground covers for a diversity of flowering weeds is the single most important tool in encouraging natural predators. Ground covers also increase the humidity and reduce soil temperatures which improve tree growth and lessen problems with spider mites. These same ground covers also provide habitat for wildlife and pollinators.
  • Fertility — Nitrogen especially will feed not only the tree but pests. Many growers have been able to reduce nitrogen use in younger trees because the clover in ground covers around trees are providing adequate nitrogen. Taking soil samples so that fertilizers are applied only when necessary is a good way not to make a pest problem such as elongate hemlock scale worse. A good fertility program also creates a stronger, faster growing tree that will reduce the rotation length (the number of years it takes to grow a tree to harvest size).
  • Culling — Fraser fir are grown from seed, and they vary greatly in their genetic make-up. Certain individuals are genetically more susceptible to pests such as mites and scales. By cutting and removing the most susceptible individuals, pesticide use becomes more effective and at times can even be avoided entirely.

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