PIN YO N PINE Management Guidelines For Common Pests JoAnne Skelly Extension Educator, Carson City/Storey County University of Nevada Cooperative Extension John Christopherson Resource Management Officer, Nevada Division of For EB-03-02 PIN YO N PINE Management Guidelines For Common Pests JoAnne Skelly Extension Educator, Carson City/Storey County University of Nevada Cooperative Extension John Christopherson Resource Management Officer, Nevada Division of Forestry Funded in cooperation with the USDA Forest Service. This reprint was made possible with funds from an Assistance Agreement with the Bureau of Land Management and Storey County Fire Protection District in collaboration with University of Nevada Cooperative Extension. Copyright © 2003, 2nd edition, 2nd printing 2016. University of Nevada Cooperative Extension is a partnership of Nevada counties; University of Nevada, Reno; and U. S. Department of Agriculture. The University of Nevada, Reno, Nevada Division of Forestry and the USDA Forest Service are equal opportunity affirmative action employers and do not discriminate on the basis of race, color, religion, sex, age, creed, national origin, veteran status, physical or mental disability, sexual orientation or genetic information in any program or activity they operate. The University of Nevada, Reno, Nevada Division of Forestry and USDA Forest Service employ only United States citizens and aliens lawfully authorized to work in the United States. CONTENTS Introduction and Description . 7 Keeping Trees Healthy . 9 Pinyon Forest Management Guidelines . 13 Common Pests . 15 Insects Pinyon Ips Beetle . 15 Red Turpentine Beetle . 17 Twig Beetle . 19 Pinyon Needle Scale . 20 Pitch Mass Borer . 22 Pinyon Tip Moth . 23 Pinyon Sawfly . 24 Diseases Black Stain Root Disease . 25 Pinyon Needle Rust . 26 Pinyon Blister Rust . 27 Pinyon Dwarf Mistletoe . 27 Conclusion . 31 Glossary . 33 References . 35 Photo Credits . 37 PINYON PINE Management Guidelines For Common Pests : 7 INTRODUCTION inyon pine (Pinus monophylla) know how to take care of the native woodlands occur on many of pines. This guide will help homeown- thPe mountai n ranges of Nevada. ers identify and manage common With development spreading into pests of pinyon pine. The guide these woodlands, home landscapes discusses general practices to often include singleleaf pinyon. maintain healthy trees, lists specific Home-owners wishing to maintain pests, and outlines management these native landscapes need to strategies. DESCRIPTION ne of Nevada’s two state trees, conifer, taking as long as 60 years to singleleaf pinyon is also one of reach about 6.5 feet. However, it theO pr edominant trees in the Great typically grows from 2 to 4 inches per Basin, growing not only in Nevada, but year with mature trees reaching 20 also in parts of California, and feet to 40 feet, depending on the site western Utah. It tolerates drier quality. Its life span can be greater conditions better than other Nevada than 600 years. pines. In the drier portions of its range, it is often found in association Across its extensive range in the with Utah juniper (Juniperus osteosper- state, pinyon is important to wildlife, ma). It grows at elevations ranging providing food and cover for many from approximately 3,200 feet to species including birds and large and 9,200 feet. small mammals. Trees are also of considerable cultural value to Native Singleleaf pinyon is a slow growing Americans of the Great Basin. PINYON PINE Management Guidelines For Common Pests : 9 KEEPING TREES HEALTHY ealthy trees have fewer insect Constant irrigation can rot pinyon and disease problems than roots, causing diseases, branch tHrees that are stressed. It is impor- dieback, and death. tant to keep trees vigorous by reducing human-caused stress factors The pinyon’s growth, starting in April such as improper irrigation, construc- and ending in September or October, tion damage, soil compaction, and is supported by stored soil moisture improper fertilizer or chemical use. rather than spring or summer rains. Watering a pinyon pine should mimic natural rain or snow, and should be Pinyon pines in home landscapes done primarily from December to require minimal maintenance. They April if a winter is unusually dry. are growing in their native habitat, and therefore are adapted to the site. During periods of drought in winter Irrigation and fertilization are typically and early spring, trees should be given unnecessary except when trees have a deep watering monthly. Keep water been damaged by human activity or away from the root crown (Figure 1, weather. next page). An exception to the “don’t irrigate Avoiding Stress Factors: Humans pinyon” rule is when trees have lost often impact trees with their daily roots due to excavation. Then it is activities. Trees that have been necessary to provide supplemental injured, above- or below-ground, are prime candidates for attack by insects irrigation to keep soil moist through and diseases. Root damage is a the growing season (May to Septem- ber). This should encourage new root common source of tree stress caused development to replace damaged by humans. roots. Be careful not to overwater; allow soil to drain between waterings. Root systems of pinyon are often Do not leave standing water in the damaged by overwatering. Because root zone. Pinyon pines need well- their native habitats are drier than drained soils. those of other pines, too much water can cause root problems and death. Construction often damages trees by Homeowners used to watering compacting soil, destroying roots, and landscape trees such as Austrian scraping bark. In order to protect (Pinus nigra) or Scotch (Pinus sylvestris) trees from construction hazards, pine regularly through the summer, protective zones should be estab- often mistakenly irrigate their pinyon lished around individual trees and similarly. Pinyon trees should never groups of trees. These zones should have irrigated landscapes planted be clearly delineated with brightly around them. colored flagging. 10 Since pinyon roots often extend out branches with a sharp knife. Do not from the trunk two to three times remove bark that is firmly attached. the tree’s height, and are located near Don’t use a sealant on wounds; leave the soil surface, it is difficult to avoid them exposed. damaging them. Therefore, it is important to consider these root systems when locating structures, Natural Target Pruning access lanes, and utility lines. Avoid 1. Find Target A — Just outside of paving over tree roots. the branch bark ridge. At a minimum, keep construction- 2. Find Target B — Swelling where related activity outside the dripline of branch meets collar. trees planned for retention (Figure 1). 3. Make cuts — Use the ‘three-cut’ method for two inch and larger limbs. Make a first cut on the underside of the branch 8 to 10 inches from where the branch connects to the trunk. Cut a third to halfway through the limb. Make the second cut from 1 to 3 inches outside the first cut, starting on the top and cutting through the branch. Make the final cut at line AB, just outside the Figure 1. Tree’s dripline and root branch collar. crown Correcting Existing Problems: Homeowners often inherit tree problems upon purchase of a proper- ty. What can be done to reduce stress factors and encourage tree vigor in this case? Prune off any broken branches or branch stubs. Pruning cuts should follow natural target pruning guide- lines (Figure 2). DO NOT: Remove any soil deeper than 6 inches • Cut behind the branch bark added during recent construction ridge over a tree’s root zone down to the • Leave stubs original soil grade. Aerate and mulch • Cut branch collar compacted soils and older fill. • Paint cuts Loose bark should be removed from Figure 2. Natural target pruning the edges of wounds on the trunk or PINYON PINE Management Guidelines For Common Pests : 11 Trees that have sustained significant and all branches up as high as possible root damage may need to be sprayed on uninfested trees. March is the with an insecticide for one to two best time to spray. Contact Nevada seasons to protect them from bark Department of Agriculture for a list beetle attack. of pesticides registered for bark beetle on pine. There are no chemical sprays to save trees that are already infested with Another corrective action that can be beetles. However, spraying uninfested taken in an existing landscape is to trees with insecticides can protect remove lawn or other plantings them during times of stress or requiring water from the area between following injury. Spray the main trunk the trunk and the dripline of the tree. PINYON PINE Management Guidelines For Common Pests : 13 PINYON FOREST MANAGEMENT GUIDELINES he management guidelines for Trees infected with dwarf mistletoe pinyon contained here are very (see page 27), a parasitic plant, and Tgeneral. Specific recommendations those with numerous branch and need to be tailored to the individual stem cankers are also good choices site and take into consideration the for removal. Insect infested trees landowner’s objectives. should be evaluated for removal as well. Retain trees that have been Thinning: One of the primary good cone producers. Look for factors leading to poor tree health is immature and old cones in the too many trees spaced too closely. branches and accumulations of fallen Thinning, the selective removal of cones beneath the tree (Figure 3). individual trees to reduce tree density, is an important management Keep large trees with healthy, vigor- practice that improves tree health ous crowns (Figure 4, next page). If and vigor and decreases wildfire your property has both pinyon and potential as well. juniper, keep junipers too. A mixed stand will help deter the spread of Little research-based information insects and diseases. exists from which to develop guide- lines for thinning in pinyon stands. Try to achieve a spacing between There are, however, many general trees that is roughly equivalent to considerations that apply to all forest one and a half times the average tree types that should be considered height.