Pinyon borers, engraver beetles and pinyon tip moths, are major insect enemies of Pinus edulis.
Pinyon "Pitch Mass" Borer (Dioryctria ponderosae)
The larvae of this moth cause the damage in pinyons. The adult moth lays eggs in July or August. Larvae are pink or yellow with a brown or tan head. They live under the pitch mass (hardened sap around a wound).
Symptoms
- Dieback of branches and twigs
- You may see what looks like large cuts or gouges on the trunk or larger limbs, and a creamy pitch coming from them
- The tree becomes disfigured.
Treatment
- This may sound distasteful to some, but the best way to control these insects (which cause millions of dollars in damage to pinyons) is to stick a small wire into the sap areas and actually pull the larvae out. This only works if the larvae haven’t tunneled in too far. There are some organic pyrethroids that can control them, but they must be applied several times a year.
Ips (Engraver) Beetles (Ips spp.)
These beetles are tiny (from an eighth to a quarter inch long), but don’t let their size fool you. Their larvae can do significant damage to pinyons. These beetles are black or red-brown. They have a cavity or basin on the back of their abdomens. The cavity is lined with spines. The larvae are small, have no legs, and are white or gray, and have black or dark brown heads.
Symptoms
- Look for tube like openings on the trunk or in crotches of the tree. These will be about three inches long and about three quarters of an inch wide.
- There will be pine dust on the bark, in crotches or even around the base of the tree.
- Needles will change color from green to yellow and finally to brownish red.
- You may also find some tiny insect galleries beneath the bark.
Treatment
- Make sure the trees are properly watered. Even though pinyons are highly drought-tolerant, in periods of elongated drought they may become susceptible to these beetles and their larvae. In addition to watering, make sure the trees are spaced far enough from other trees and vegetation. You may even need to add nutrients,..
Pinyon Tip Moth (PTM) (Dioryctria albovittella)
Pinyon Pitch Nodule Moth (PPNM) (Retinia arizonensis)
The adults of both species are small gray moths, while the larvae are gold or light brown with a dark brown head. The larvae bore into terminal buds and new growth, causing more and more damage as they feed.
Symptoms
- The tree might become disfigured.
- You might see holes in the pinyon cones
- There is a wound on the tree with a lot of pitch or sap around it.
- There is twig dieback
Treatment
The adults are exposed in midsummer. Spray the trees with a hard spray of water to dislodge the beetles and knock them off the trees.
Other pests:
Pinyon Needle Scale (Matsucoccus acalyptus)
Pinyon Spindlegall Midge (Pinyonia edulicola)
There are chemicals which can help control these insects and their larvae, but insecticides are indiscrimate killers, destroying beneficial insects as well as undesireable ones.
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