Homeowners Urged To Beware Of Infestation Threatening Pinyons

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Photo courtesy of Arizona State Forestry Division

Payson residents should look out for this yellow growth on pinyon pines left by pinyon needle scales and take steps to wash away the infestation to save their trees.

The Arizona State Forestry Division has issued a warning to Payson residents to be on the lookout for a pine-tree-killing disease carried by beetles.

The female pinyon needle scales have already laid their eggs in the Payson area. This native insect which defoliates and kills pinyon pines has been identified in southeast Payson, the Trailwood subdivision on the west side of town, Beaver Valley Estates and Round Valley.

Due to the recent warm weather, 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 after egg laying is completed.

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.

Most likely to die from the annual defoliation by the insect are pinyons growing on drier rocky outcrops, south- and west-facing slopes and transitional zones between pinyon-juniper and grassland vegetation types.

Control of this stage of the insect involves — 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.

Repeated washings may be necessary since not all eggs will be laid at once. 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.

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.

Also refer to the pinyon needle scale publication issued by the Cooperative Extension at: http://cals.arizona.edu/

pubs/insects/az1315.pdf and their watering brochure at: http://cals.arizona.

edu/pubs/water/az1298.pdf. For information on fire prevention treatments: www.firewise.org. For further information, contact Bob Celaya, forest health specialist, Office of the State Forester, at (602) 771-1415 or the Payson Field Office at (928) 474-2689.

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