Pinyon Needle Scale Eggs Hatch Threaten Life Of Pines

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According to the Arizona State Forestry Division, female pinyon needle scales have already laid their eggs in the Payson area, says Bob Celaya, state forester.

This complex native insect which defoliates and kills pinyon pines can be found in southeast Payson, the Trailwood subdivision on the west side of town, and Beaver Valley Estates and Round Valley in Gila County.

Due mainly to the recent warm temperatures, female scales have already emerged from their over-wintering stage on the needles in these areas.

Very noticeable clusters of yellow eggs held together in loose, white, cottony webbing have been laid by the females mainly in branch crotches, along the underside of branches, on the trunk, and at the base of the tree. The females die shortly afterward and are the dark objects seen in the egg masses.

Heavily infested pinyons can be easily detected by the yellow or orange discoloration of the older needles toward the back of the branch.

The needles are covered with small, black, bean-shaped scales which pierce the foliage and remove the sap, causing the needles to discolor, dry, and fall off. Small trees may be killed within a few years; whereas, larger trees may lose one or more branches and may take years to die.

Egg removal

Control of this stage of the insect involves several steps:

• Step 1: Washing the eggs off branches and trunk with a garden hose equipped with a high pressure nozzle and allowing eggs and litter one to two days to dry.

• Step 2: Raking eggs, litter and debris out from under the tree, and

• Step 3: Disposing of the eggs in plastic garbage bags. Raking may not be practical if heavy brush, rocks or other material is present under the tree. However, washing the eggs off the tree is still recommended.

Removal of the eggs from your pinyons will be simplified if you have already treated your vegetation for fire prevention reasons.

“Examine the tree closely for egg masses in branch crotches which are usually overlooked.”

If you wash too late, eggs will have hatched and the young scales (crawlers) will have moved to the needles where they can be treated with insecticides. Egg hatch usually occurs in May; providing a long period of time for egg removal — but the sooner you remove them the better!

Unless there are local water restrictions, consider slow, deep, and infrequent watering of your infested pinyons nearest your home, starting as soon as your soils dry out, with a soaker hose placed around the drip line of the tree. Continue watering until “monsoon” rains are well established.

More information

Also refer to the pinyon needle scale publication issued by the Cooperative Extension at: http://cals.arizona.edu/pubs/insects/az 1315.pdf and their watering brochure at: http://cals.arizona.edu/pubs/water/az1298.pdf. And fire prevention treatment information: http://ag.arizona.edu/firewise/.

For additional information about this insect, or other forest health concerns in the Payson area, contact: Bob Celaya, forest health specialist, Office of the State Forester, at (602) 771-1415. bobcelaya@azsf.gov.

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