Gardening From The Ground Up

 


.
Site map

[ What is a Garden ] [ The Gov.  and the scientist. ] [ Frequent Questions ] [ Landscape horticulture ] [ The Biosphere ] [ NM Soils ] [ Botany ] [ Native Trees and Shrubs ] [ Plants for NM ] [ Vegetable Varieties ] [ Fruits ] [ Grass1 ] [ Plant Disease Defined ] [ Pest Management (IPM) ] [ Weeds ] [ Water Gardening ] [ Drip Irrigation ] [ Composting ] [ House plants ] [ Other Resources ]
What's New

Tomatoes 2008
Composting.ppt
Iris with music.ppt
Flowers and bulbs in garden.ppt


 

Remember the piņon! New Mexico Bark Beetle Epidemics
Fact Sheet and Information Bulletin
January 2003
(from the USDA Forest Service)

 

  1. GENERAL:
    1. Much of New Mexico is currently experiencing a large upswing in piņon and ponderosa pine mortality due to outbreaks of several species of Ips beetles and the western pine beetle. Low tree vigor caused by several years of drought and excessively dense stands of trees have combined to allow bark beetle populations to reach outbreak levels.
    2. These insects are native to piņon-juniper woodlands and ponderosa pine forests of the Southwest, normally attacking only a small number of diseased or weakened trees. Healthy trees are usually not susceptible to these beetles.
    3. The bark beetles are tiny, roughly 1/8 inch long, or about the size of a match-head.
    4. These beetles have multiple generations per year, and when conditions are favorable, they have a tremendous capacity to increase their populations.
    5. The beetles attack trees by chewing through the outer bark and laying eggs. When the eggs hatch, the larvae feed on the soft, nutritious inner bark. Also, the beetles introduce a blue-stain fungus that spreads through and clogs the water and nutrient-conducting tissues, hastening tree death. Once the insects mature, the leave the infested tree and travel to a new host. Usually, the travel only a short distance, but they are capable of moving up to 1/2 mile or more.
    6. Millions of piņon trees have already been killed, mostly where piņon and juniper grow together. Juniper is unaffected by the insect attacking the piņons. In some localized areas, up to 70% of the piņons have died, leaving only the smallest seedlings to survive. Even then, small piņons may be vulnerable to another, less aggressive insect, the twig beetle. Ponderosa pine mortality is also on the increase, although not at the scale of piņon. This is the worst bark beetle epidemic in the Southwest in almost 50 years. If the drought persists, more trees can be expected to die.
    7. Currently, tree mortality is centered in stress-zones such as drier south-facing slopes, transition areas between ponderosa pine and piņon-juniper areas, recent construction sites, and areas heavily infected with dwarf mistletoe.
    8. Infested trees will start to turn reddish-brown within a month of attack. Evidence of infestation can include sawdust at the tree's base or in bark crevices, small popcorn-like masses of sap called pitch tubes, small boring holes, and a fading of the needles. If the tree is extremely drought-stressed, it may not produce pitch tubes, which are its natural defense against the beetles.
    9. Once beetles have left a tree, it no longer poses a threat to other trees as a source of beetle infestation.
  2. TREATMENT:
    1. There is nothing that can be done to save a tree after it has been successfully attacked by bark beetles and infected with the blue-stain fungus. If the goal is to kill the beetles under the bark, then infested trees must be cut down and treated by one of the following methods:
      • Pile and cover logs with clear plastic in a sunny site (this produces high temperatures by a greenhouse effect),
      • Peel the bark from logs, or
      • Burn, chip, or bury the logs. (It must be noted that fresh pine chips can attract Ips beetles and should be immediately removed from forested sites.)
    2. Fresh pine debris over 4 inches in diameter, created during tree thinning operations, must be removed from the forest or treated as noted above to prevent it from becoming breeding material for Ips beetles.
    3. There is no effective insecticide treatment for infested trees. Injecting trees with systemic insecticides is not an effective method of control or prevention due to the feeding location of the beetles within the inner bark.
    4. Be aware that removal of actively infested trees may not be an effective treatment option during an epidemic because of the difficulty in detecting and removing all green-infested trees, the asynchrony and rapidity of beetle reproduction, and the sometimes overwhelming opportunities for re-infestation from adjacent untreated properties.
    5. Due to the extent of the outbreaks and the tremendous capacity of bark beetles to reproduce, the implementation of effective large-scale control actions to prevent further tree losses is not feasible.
  3. PROTECTING HIGH-VALUE TREES:
    1. Trees not yet infested can be protected by annual applications of a preventive insecticide. Carbaryl and permethrin are specifically labeled for this purpose, but carbaryl is the preferred material because it provides longer protection. Typical home and garden insecticides should not be used. The entire surface of the trunk and large limbs must be thoroughly sprayed. Ips beetles will attack any limb or trunk 3 inches in diameter or larger, so care must be taken to treat to these diameter minimums.
    2. Over the long run, reduction of tree density, disposal of the resulting woody debris, and appropriate use of prescribed fire, will not only improve forest health, but also greatly reduce the probability of bark beetle outbreaks and catastrophic wildfire.

 

For further information, contact:

Debra Allen-Reid, USDA Forest Service, Forest Health New Mexico Zone Leader, at 505-842-3286; George Duda, Urban Forester, New Mexico State Forestry, at 505-476-3332; or your local New Mexico State Forestry District Office. Local county extension agents also can provide assistance. Additional information can be obtained at: