Pest Fact Sheets
The pest fact sheets on pages 23–71 are for disease, insect, and mite pests that damage needles and result in defoliation, discoloration, or distortion. The damage can vary from slight yellowing of needles to total loss of needles. Tree death is uncommon and only occurs if a pest population is unmanaged for several seasons.
Diseases, insects, and mite pests that kill or cause serious damage to new growth and entire branches are discussed on pages 73–104. The damage may distort or kill the shoot or branch but usually does not result in death of the entire tree.
Entire trees may be killed by the diseases and insects on pages 107–121. Some of these may be associated with other pests that initially weaken a tree but are not capable of killing it. The combination of pests can result in rapid death of some conifers.
Other factors beyond disease, insect, and mite pests can cause signifi cant damage to Christmas trees that may resemble pest damage. These factors fall into two broad categories. The abiotic factors include those not caused by living organisms as well as chemical, environmental, and mechanical damage. The biotic factors are those caused by several vertebrate pests. Both of these types of damage are discussed on pages 123–129.