United States Department of Agriculture Conifer Pests in Forest Service New Mexico
Southwestern Region Prepared by: Roliert Cain and Douglas Parker
New Mexico State University - Cooperative Extension Service * Robert Cain is with New Mexico State University Cooperative Extension Service and Douglas Parker with USDA Forest Service, Southwestern Region.
This publication is a revision of Insects and Diseases of Evergreens in New Mexico prepared cooperatively by New Mexico Department of Agriculture, USDA Forest Service, New Mexico Division of State Forestry, and USDA Cooperative Extension Service in 1977. Special acknowledgement is given to Anthony Smith who prepared much of the original version.
Revised and printed on recycled paper • 9/98 Table of Contents
Introduction ...... ~ .< ...... 1 Insect and Mite Pests Pinyon Needle Scale ...... 3 Pine Needle Scale ...... 5 Pinyon Spindle Gall Midge ...... 7 Needle Miners ...... 8 Tiger Moth ...... 10 Douglas-Fir Tussock Moth ...... 11 Western Spruce Budworm ...... 13 Conifer Sawflies ...... 15 Conifer Aphids ...... 16 Cooley Spruce Gall Adelgid ...... 18 Spider Mites ...... 20 Pine Tip Moths ...... 21 Pinyon Pitch Nodule Moth ...... 22 Spittlebugs ...... 23 Bark Moths and Pitch Moths ...... 24 Twig Beetles ...... 26 Bark Beetles ...... 27 Roundheaded and Flatheaded Wood Borers ...... 31 Western Cedar Borer ...... 32 Juniper Twig Pruner ...... 33 Disease Pests Mistletoes ...... 34 White Pine Blister Rust ...... 36 Stem Rusts of Junipers ...... 37 Broom Rusts ...... 38 Branch and Shoot Dieback on Spruce ...... 39 Root Rots ...... 41 Needle Diseases ...... 42 Other Problems ...... 43 General Chemical Recommendations and Precautions ...... 45 General ized Pesticide Control Strategies for Conifer Pests in New Mexico ...... 47 References ...... 49 Introduction
This guide is intended to help 12 to 18 inches. Prune roots in homeowners and forest managers in November, December, or January identifying and controlling forest while the tree is dormant. Conifers and ornamental tree pests. The must be moved with a ball of soil guide focuses on insect and disease held firmly intact around the roots . pests but also discusses natural and Use tightly wrapped burlap to keep human-caused environmental the soil from crumbling during problems. transportation and handling. It's important to remove burlap, Many pest problems can be chicken wire, or any other material prevented by keeping trees healthy used to wrap the root ball when and vigorous. Tree pests are usually resetting the plant in the ground. attracted to and do more damage to These materials often don't rust or stressed, weakened trees. In forests, rot away in dry Southwestern soils environmental stresses can and the trees wi II remai n root sometimes be alleviated by thinning bound. Please note that white pine stands to reduce competition among wildlings from Southern New trees. In urban landscapes, trees are Mexico should not be transplanted often planted in areas where they elsewhere to prevent the spread of would not grow naturally and thus white pine blister rust. may suffer from too much or too little moisture, soil compaction, The following pages include alkalinity, air pollution, and descriptions of pests, pictures of exposure to sun and wind. In urban damage, and pictures of the areas throughout New Mexico, damage-causing organism wherever conifers need supplemental water possible. Options for mechanical during the windy spring and at and biological control are provided other dry times during the year. where such alternatives are effective. At the end of this Transplanting wild grown conifers publication is a list of to urban areas poses other recommendations for specific problems. Conifers growing in New pesticide control. Remember that Mexico's dry soils have extensive pesticide recommendations are root systems. Generally, few of the subject to frequent changes in roots remain intact when the trees registration and pesticide use are dug so many transplanted trees regulations. For current die. The larger the tree chosen to recommended controls, contact transplant, the less likely it will your county agriculture extension survive. Younger trees are more agent or the Cooperative Extension vigorous, have smaller root systems, Service at New Mexico State are easier to dig, and will quickly University. Or contact the New grow to a size equal to that of Mexico Energy, Minerals, and larger, more costly transplants. You Natural Resource Department's can double the survival rate by Forestry and Resources pruning roots 12 months or more Conservation Division in Santa Fe, before diggi ng. Cut them with a New Mexico; New Mexico narrow pointed shovel from 1 to 3 Department of Agriculture, Las feet out from the tree to a depth of Cruces, New Mexico; or USDA Forest Service, Region 3, Forest you first obtain a written permit Health, Albuquerque, New Mexico. from the landowner or land manager. If you plan to dig or sell State law prohibits removing any plants, first apply for a Collected plant within 300 feet of a public Plant Inspection Certificate and/or a thoroughfare. The law also requires Dealers License from the New that before removing any plants, Mexico Department of Agriculture.
2 Pinyon Needle Scale Matsucoccus acalyptus (Herbert)
Pinyon needle scales are small, previous fall and spent the winter as black, bean-shaped bumps on the prepupae in silk webs in litter surface of one-year-old pinyon beneath the tree. A few males don't needles. These tiny, sap-sucking enter the prepupal stage until early insects kill the needles and seriously spring. Mated females lay yellow weaken pinyon pines in forests and eggs in clusters held together by used as ornamentals. Reduced new white, cottony webbing around the growth and stunted needles are root collar, on undersides of large common on trees suffering repeated branches, in branch crotches, or in attacks. Heavy infestations cracks of rough bark. Occasionally, frequently kill small trees and egg masses are found several feet predispose weakened larger trees to from the base of the tree on a rock attack by other insects, especially or log. About four weeks after eggs bark beetles, which can kill trees. are laid, tiny, red eye spots can be seen in the eggs with the aid of a hand lens. Nymphs, called crawlers, emerge about 7 to 10 days after eye spots appear. They climb to the ends of branches and settle on the previous year's new growth. After inserting tubelike mouth parts into the needle, they become immobile, cover the body with wax, and turn black.
BIOLOGY: Adult, wingless females emerge from scale coverings in late winter or early spring and mate with winged males. Emergence time in Southern New Mexico communities is mid to late February; in Albuquerque it is early to mid March; and in Santa Fe and Los Alamos it is mid-March to early Heavily infested pinyon. Only the new April. Most males emerged the growth remains green.
3 CONTROL: Potential damage from hand lens and be ready to spray these pests can be drastically shortly after the crawler's red eye reduced by destroying eggs before spots are visible. Once scales have they hatch. Dislodge egg masses established themselves on the from the tree with a strong stream of needles, they become more difficult water from a garden hose. After to control. Additional direct control washing down the tree, rake up all information is provided on page 47. the material around the base of the tree and destroy or remove it. Chemical insecticides are registered to control the pinyon needle scale, but timing of the spray application is critical for success. Apply insecticides to the bark and branch crotches as soon as crawlers begin to emerge. Exami ne eggs with a
Female scales migrating to egg-la ying sites in the cracks or-rough bark.
Female scale emerging from scale covering and being mated by winged male.
Cottony webbing and eggs laid at the base of tile tree trunk.
4 Pine Needle Scale Chionaspis pinifoliae (Fitch)
Pine needle scale is a common pest BIOLOGY: The pine needle scale of most pine species, spruce, and has two generations per year. The Douglas-fir. Damage is especially eighth-inch-Iong mature female noticeable on ornamental pine and scales are most conspicuous. They spruce trees growing along dusty are almost pure white, slender at the roads. Insects feed by sucking sap front end, and wider at the rear end. from needles, causing the needles to Males are smaller, more slender, yellow and eventually drop. Heavy and rarely seen. Twenty to 30 eggs infestations over several years can are laid in the fall and winter kill young trees and severely beneath the dead female scale. weaken larger trees, predisposing Eggs hatch in May and the nymphs them to attack by other pests. or "crawlers" move to the new green needles to feed . Nymphs mature by early July, adults mate, and new clusters of eggs are laid. Scales of this second generation mature by fall and lay the overwintering eggs .
Enlarged view of female scale on a single needle.
5 CONTROL: Inspect trees for scales contact insecticides. Summer or before digging or purchasing for horticultural oils may improve transplant. On established trees, effectiveness but they can discolor apply a foliar systemic insecticide or burn plants if not applied (see page 47) in May and early June correctly. Cutting or burning small to provide some control of heavy infested trees is the only effective infestations. Insecticides should be cultural control alternative to applied just before eggs hatch and chemical insecticides. Ladybird then once or twice more at 7-10 beetles and a few species of day intervals to control nymphs parasitic wasps usually keep hatching later. Adult insects are populations of this pest below protected by a waxy covering and seriously damaging levels. almost impossible to kill with
6 Pinyon Spindle Gall Midge Pinyonia edulicola Gagne'
Pinyon spindle gall midge produces CONTROL: Controlling this pest a spindle-shaped swelling from the usually isn't necessary. Landscape needle base that is about a half-inch trees under stress that develop long. The insect is a common forest heavy infestations, may require pest that rarely causes serious treatment with a registered systemic damage. However, in urban insecticide (see page 47). Apply the settings heavy infestations can insecticide when eggs are laid and cause serious defoliation as galls dry hatching starts in late June and early and needles drop prematurely. July.
BIOLOGY: The pinyon spindle gall midge is a tiny fly about 1/16-inch (3-4 mm) long. Adults lay eggs on needles in late June and early July. Larvae hatch soon afterward and mine into the cu rrent year's needles, causing galls to form. Each gall contains from 5 to 40 small, orange, legless maggots. Larvae overwinter in the galls and pupate in the spring.
Needle gall.
Tiny, orange maggots inside gaiT.
7 Needle Miners Pinyon Needle Miner Coleotechnites edulicola Hodges and Stevens
Ponderosa Pine Needle Miner Coleotechnites ponderosae Hodges and Stevens
Needle miners are locally common BIOLOGY: Pinyon needle miners on pinyon and ponderosa pine. lay eggs from early June through Species resemble one another in mid-July. larvae emerge soon after appearance and damage but have eggs are laid and bore into different life cycles. Damage first uninfested needles where they feed becomes evident as foliage browns. until fall. They overwinter inside the Closer examination reveals needles as dormant larvae. Feeding hollowed-out needles. Early needle resumes in the spring and larvae drop, reduced growth, and tree grow to about 3lB-inch (5 mm) long. mortality can all result from needle Pupation occurs in late May. miner infestations. The severity of the infestation varies significantly from tree to tree, suggesti ng that individual trees have some resistance to these pests.
Pinyon needle miner exit hole.
Ponderosa pine needle miner inside needle.
B Ponderosa pine needle miners lay CONTROL: Trees usually recover eggs in late summer inside from needle miner damage without previously mined needles. The suffering serious injury. For direct newly hatched larva bores into the control, use a foliar systemic tip of a green needle and mines insecticide after eggs have hatched slowly through the winter, (see page 47). developing more rapidly as the weather warms and then pupating in mid-summer.
Pinyon needle miner damage.
9 Tiger Moth Halisidota spp.
Tiger moths are most often encountered on ponderosa and pinon pines and occasionally on juniper and Douglas-fir. Natural enemies generally prevent them from becoming a serious forest pest. Webbing and branch defoliation caused by tiger moths is unsightly on ornamentals.
BIOLOGY: Tiger moths produce one generation per year. Adult moths Tiger moth caterpillars. emerge from mid-July to late August. Females lay clusters of returning to the tent before nightfall. light green eggs on needles and By early spring, tents are large, twigs of host trees. Eggs hatch in 3-6 conspicuous, and filled with masses weeks . The small gregarious larvae of dead needles. are dark brown to black and quite hairy. Groups of young feed on As caterpillars reach their full current needles and form webs or growth, they feed alone away from tents enclosing a portion of the the tent, often migrating to another branch. Feeding continues through tree. Full-grown caterpillars are the fall and larvae overwinter in about 1-1/2 (3.5-4 cm) inches long tents. Tents are usually located in and covered with yellow-brown to the topmost branches or on the trees' dark brown hairs that can cause a south and west sides. larvae will ski n rash on people sensitive to feed outside the webbing on warm them. In June, mature caterpillars sunny days throughout winter, spin brownish cocoons of silk and body hairs. These cocoons are attached to branches, limbs, and trunks of the host trees and occasionally to debris on the ground.
CONTROL: Chemical insecticides and the bacterial insecticide, B. t. (Bacillus thuringiensis), are available but not usually necessary. Remove tiger moth infestations by simply pruning and destroying branches with tents while Tiger moth tent. larvae are resting inside.
10 Douglas-fir Tussock Moth Orgyia pseudotsugata (McDunnough)
The Douglas-fir tussock moth is one of the most destructive pests on ornamental Douglas fir, white fir, and blue spruce in New Mexico. Needles in the upper portion of infested trees may be completely removed after one or two years of feeding. In Southwestern forests, tussock moth outbreaks have generally been confined to 'overmature, multi-storied stands of white fir and Douglas-fir.
BIOLOGY: Eggs hatch from Wingless female laying eggs in frothy mid-May to early June and mass. caterpillars feed on the current year's developing foliage. Young is wingless, the primary means of larvae are 1/8 to 1/4 inches (4-7 dispersal from tree to tree is by mm) long and covered with long, windblown larvae. Young larvae thin body hairs that later develop congregate on the tops of defoliated into tufts. Because the female moth trees and drop on silken threads that may be over 10 feet long. These threads eventually break from the tree and give a ballooning effect to the larvae. If caught by a strong wind, some larvae may be blown great distances. Many of the larvae will never find a suitable host and perish during dispersal.
Mature larvae are up to 1-1/4 inches (31 mm) long and very colorful. Behind the head are two long, dark tufts of hair that resemble horns projecting forward. On the posterior is a longer tuft of hair projecting backward. In the middle of the back are four dense, buff colored tussocks. Short hairs radiating from red, buttonlike centers cover the rest of the body except for the head and legs. Some people develop an itchy rash from exposure to the frequently airborne Mature larva. caterpillar hairs.
11 Older caterpillars do the most CONTROL: Without some form of damage. After they are about half control, ornamental trees can be grown, they feed on new and older completely stripped of all needles foliage lower in the crown and and die. Both chemical and farther back on the branches. biological insecticides are registered for use against the Douglas-fir tussock moth. The microbial insecticide, B.t. (Bacillus thuringiensis), can provide an effective alternative to chemical control although results have been variable. Early treatment and multiple sprays improve resu lts. B.t. is a bacterium that produces a toxin lethal to many kinds of moth larvae. Spray it during dry weather on small larvae when the egg hatch is finished and leaf extension 40 to 50 percent complete. Chemical insecticides (see page 47) are also most effective when applied to the small larvae. Don't use these chemicals near water or bee hives; they're toxic to both fish and bees. Egg and larval parasites, a vi rus, general insect predators, and birds also help control outbreaks of Cocoon on underside of branch. this pest.
Pupation occurs inside a thin, silk cocoon spun on the undersides of branches from late July to the end of August. Adults emerge within 10 to 18 days, depending on temperature.
The female moth has only rudimentary wings and cannot fly. She emits a chemical sex attractant and soon mates. If undisturbed, all of her eggs will be deposited in a si ngle mass on top of the cocoon from which she emerged. From 150 to 300 eggs are laid in a dry, tough, frothy substance covered with hairs from the female's body. Overwintering occurs in the egg stage.
Defoliation by' Douglas-fir tussock moth often kif's the top of the tree.
12 Western Spruce Budworm Choristoneura occidentalis Freeman
The western spruce budworm is a Newly hatched larvae are often serious forest pest that also damages dispersed by the wind to other ornamental and Christmas trees branches. After a few days, they growing at higher elevations. The seek overwintering sites under bark budworm attacks Douglas-fir, white or cone scales, between needles, or fir, and spruce. Outbreaks are in other protected spots on the tree. periodic and can last from several They emerge the next May and years to over a decade. Damage chew paths through buds or feed at from budworm outbreaks includes the base of new needles on tree mortality, top-killing, and expanding shoots. As they feed, growth loss. Defoliation in they produce a silk webbing that recreation areas is unsightly and catches uneaten needles. These camping and picnicking can be needle remnants dry, turn red, and discouraged by large numbers of make the tree look scorched. The dispersing larvae. final two larval stages may be 25 to 32mm long and account for most of BIOLOGY: Western spruce the defoliation. As new needles budworm moths are about an inch become scarce, larvae disperse on long (22 to 28 mm) and mottled silk threads to the understory or gray to orange-brown in color. Eggs adjacent trees. are laid on the undersides of needles throughout the crown of Pupation occurs from late June to host trees from early July through mid-July and lasts about 10 days. mid-August. About 50 (range 15 - Adult moths emerge between late 120) pale green eggs are laid in two June and early August, depending or three rows. like fish scales, each on locality and weather conditions. egg overlaps the preceding one. Hatching usually occurs within seven to 10 days.
Larvae hatching from egg masses on needles.
13 CONTROL: At least 40 species of small larvae during dry weather. insect parasites attack the budworm; Chemical insecticides (see page 47) however, when weather and stand are also most effective when conditions are favorable, artificial applied to early larvae. In forests, controls may be necessary to keep reduce budworm potential by budworm populations in check on thinning stands to remove Douglas high value trees. Both chemical fir and white fir and by heavy and biological insecticides are regeneration cuts that favor the registered for use against the establishment of pine and aspen. western spruce budworm. The Thinning to reduce stand density microbial insecticide Bacillus will also increase vigor and reduce thuringiensis (B.t.) provides an stress on remaining trees. effective alternative to chemical control. B.t. is a bacterium that produces a toxin lethal to many kinds of moth larvae. Spray it on
Infested, expanding shoot.
14 Conifer Sawflies Neodiprion spp., Zadiprion spp .
Conifer sawflies can be divided into two groups-the "spring" and "summer" sawflies. Spring species generally feed on old needles so the new foliage remains and trees are never completely defoliated. However, summer sawflies feed on new needles first and then attack older needles. Defoliation by summer sawflies results in greater growth loss and more frequent tree mortality.
CONTROL: Since the insects feed in colonies, simply wash the larvae off with a high pressure hose, prune infested branches, or pick the larvae off by hand. For larger outbreaks, you may need to use a registered insecticide (see page 47).
Adult female sawfly and eggs laid in slits on needle.
BIOLOGY: Adult sawflies are wasplike insects less than a half inch (11 mm) long. The female uses a sawlike ovipositor to cut slits into needles where eggs are laid. Most sawfly larvae feed in groups of 50 or more. Young larvae skeletonize the needles. Older larvae consume needles entirely. larvae resemble caterpillars but have six or more pairs of abdominal prolegs and one pair of eye spots on the head. There is wide variation in Gregarious sawfly larvae clustered color; many species are dark around branch. green or black. 15 Conifer Aphids Cinara spp.
There are many species of conifer Aphids feed by piercing the bark of aphids in New Mexico that attack branches and twigs and sucking out pines, true firs, Douglas-fir, and large amounts of sap. Because they spruces. Many of these are specific can't use all of the liquid portion of to a particular genus of tree, some the sap, they expel much water, even to a particular species. sugar, and other compounds. This Conifer aphids are rarely a concern sweet, sticky substance is called in the forest but often an annoying honeydew and is often covered pest on ornamentals around homes. with a black fungus called sooty Heavy infestations cause foliage to mold. Ants, bees, and wasps are yellow and stunt the growth of attracted to the honeydew. When young trees. Needle growth is aphid populations are high, reduced, twigs dry, and heavy honeydew rains down, covering defoliation occurs with excessive lower branches and objects below feeding. Occasionally, even larger the tree. Sometimes it appears as trees are so weakened that they die though the tree and adjacent area in a few seasons or are attacked by were sprayed with crude oil. other insects.
Aphid eggs on ponderosa pine needle.
Spruce aphid defoliation on Colorado blue spruce.
16 BIOLOGY: Most species are quite CONTROL: Several chemical large for aphids, up to 1/4 inch pesticides (see page 47) and (6mm), and are generally dark in insecticidal soaps effectively control color. In the fall, females lay shiny, conifer aphids. The timing of spray black eggs that resemble very tiny application or other chemical jelly beans on the twigs and control measure isn't as critical to needles. Eggs hatch in the spring successful control as with other and the females soon begin insects. Damaging populations producing live young without should be present before taking any mating. There are a number of control action. low populations are generations per year with both effectively controlled by a host of winged and Wingless forms. natural enemies.
Aphid on spruce branch.
17 Cooley Spruce Gall Adelgid Adelges cooleyi (Gillette)
Cooley spruce gall adelgid is the galls begin to dry and open, most common gall-forming adelgid allowing the full-grown nymphs to on spruce in New Mexico. The crawl out to the needles. Nymphs galls are cone-shaped or pineapple molt into winged adults and fly shaped. The insect is not usually back to Douglas-fir to lay eggs. This considered a forest pest, but is generation of nymphs secretes a often troublesome on ornamental waxy, woolly covering over their spruce and in Christmas tree bodies as they feed. The insects plantations where large numbers of look like little balls of cotton galls are aesthetically damaging. clinging to needles. Occasionally, Galls don't seriously affect overall heavy infestations on Douglas-fir tree hea Ith. will look like snow on the tree. Feeding causes yellow spots on the BIOLOGY: Generally, winged needles and may cause distorted females fly from Douglas-fir to needles. Eventually, another spruce where they lay eggs at the winged form is produced that bases of newly expanding buds in migrates back to spruce, completing early spring. Nymphs hatch from the life cycle. eggs and begin feeding at the bases of growing needles. In response to chemicals injected by feeding nymphs, the tree quickly envelops the insects in rapidly developing galls. Young galls are green to purple and become purplish or reddish brown with age. Galls contain 50 to 350 nymphs and are usually from 1 to 3 inches (25- Alternate life-stage or "wolly aphid" on 75mm) long. In mid-July, Douglas-Fir.
Galls on spruce.
18 CONTROL: There are insedicides or discoloring foliage when using (see page 47) to control the adelgid; oils. On small ornamentals, prune however, timing of the spray is off galls before adults emerge. It difficult to determine for effective may also help to plant spruce or control. Dormant oils applied Douglas-fir exclusively, rather than before buds swell have effectively planting the species together. controlled the overwintering stages . However, there is a risk of injuring
19 Spider Mites Oligonychus spp ., Tetranychus spp .
Although these tiny arthropods have The spruce spider mite, six legs when they hatch from the Oligonychus unungius Uacobi), and egg, they're not insects. After the two-spotted mite, Tetranychus molting once, they become eight urticae (Koch), appear to be the legged. There are a number of primary species found in New species that may be green, yellow, Mexico. orange, or red, often with dark pigmented patterns. Spider mites CONTROL: Wash the plants with a feed on a variety of conifers but are strong stream of water to remove most likely to be a problem on many of the mites and help keep the spruce and juniper. Feeding population in check. For large symptoms resemble those of aphids plantings, there are a number of and scales - spotting, yellowing, miticides registered as well as and premature dropping of needles. insecticidal soaps, and dormant and Webbing and associated eggs, cast summer oils (see page 47). skins, and live mites are also characteristic. The webbing can become obvious if it becomes covered with dust.
BIOLOGY: Spider mites have piercing-sucking mouth parts and damage trees by sucking plant juices from needles. Numerous generations can be completed in a single year and the population can explode in hot, dry conditions in the absence of natural Comparison of clean (left) and mite enemies. infested, dusty foliage.
Closeup of spider mite and eggs.
20 Pine Tip Moths Rhyaciona spp.
There are at least eight different species of pine tip moths in New Mexico. All species mine in the buds and terminal shoots. Injury is most severe on trees under 12 feet tall that may be stunted or deformed by heavy infestations. Hosts include ponderosa, pinyon, eldarica (Afghanistan), and other pines. Damage to pine shoot.
BIOLOGY: Most species have one tips or shoots, in bark crevices, or in generation per year; the Nantucket litter below the tree. pine tip moth has two to four generations. Eggs are laid on new CONTROL: Heavily attacked shoots or terminal buds from March ornamentals may require through June depending on the insecticidal control (see page 47). species. Newly-hatched larvae feed Timing of control is critical for for a short time at the bases of success. Control the newly hatched needles. They then bore into buds, larvae before they bore into the laterals, and terminals, and mine shoots. Use pheromone traps to out the pith from the tip down to monitor moth populations to the base of the shoot. The point of determine times of peak egg-laying. attack is marked by a small resin flow, but no pitch nodule is formed. The southwestern pine tip moth, The larvae are yellow to orange to which is common in northern New brown and are 1/2 to 3/4 inches (10 Mexico, can be reduced by to 20mm) long when full-grown. destroying the overwintering pupal Tip moths, depending on the stage. Pupae of this species are species, overwinter as pupae in the found attached to the root collar of the tree in plasterlike cocoons.
Severely damaged ponderosa pine. Nantucket pine tip moth adult. 21 Pinyon Pitch Nodule Moth Petrova arizonensis (Heinrich)
Pinyon pitch nodule moth attacks Pupation occurs inside the pitch pinyon pines throughout New nodule in June. Pupae move just Mexico. Attacks are characterized below the surface of the pitch by fading branch tips and nodules before they emerge as adults. of pitch formed at the insect's feeding sites. The pitch nodules are hollow balls of pitch 1/2 to 1 inch (10-2Smm) long, round, smooth, and often light purple or red. They're most often found at the crotch of two or more twigs. The fading twigs eventually lose their needles and' fall off. Leaders are occasionally damaged and forked trees may result.
BIOLOGY: The pinyon pitch nodule moth has one generation per year. The small, rusty-brown moths emerge through holes in the pitch nodule in late June and early July. Eggs are laid on needle sheaths of the current year's growth. Newly hatched larvae feed on young Reddish-brown "pitch nodule" and needles before boring into the bark fading needles characterize new attack. at nodes or whorls of twigs or branches. Full-grown larvae are about 1/2 inch (10mm) long, reddish yellow with a black head CONTROL: There are no registered and a dark area behind the head. insecticides to control this insect. In the forest, top-killing of pinyon is rarely important. On valuable ornamental trees, control the insect by pruning and destroying the infested tips as they fade in Mayor early June before the adult moths emerge. On branches and stems, destroy larvae by crushing them within the pitch nodule.
Dead tips and crusty pitch nodule with adult exit hole.
22 Spittlebugs Aphrophora spp. Clastoptera spp.
Spittlebugs feed on many conifer Nymphs are soft-bodied and white species in New Mexico but those to brown. As they feed, they found on juniper are most often produce masses of "spittle" by noticed. The insects are internally blowing air through a characterized by spittlelike froth viscous sugar solution and releasing produced by feeding nymphs. The froth through the anus. The spittle insect's feeding causes no serves both as a protective device significant damage to forest or and as a means of reducing ornamental trees. Scattered twig evaporation. Nymphs shed their mortality may be seen in the crown skin five times before molting into of infested trees. winged adults. Adults continue to feed all summer on sap from twigs BIOLOGY: Adult spittlebugs but do not produce a spittlemass. (froghoppers) are very active and superficially resemble leafhoppers. CONTROL: Spittlebug injury isn't Most species lay eggs in serious in New Mexico and doesn't midsummer in rows on the foliage. warrant control, but spittlemasses Eggs hatch the following spring. on ornamentals can be unsightly. Nymphs of some species drop from Use a strong stream of water from a the trees and feed on understory garden hose to dislodge nymphs shrubs while those of the juniper and wash away the spittlemasses. spittlebug remain on the trees.
Juniper spittlebug spittle mass.
23 Bark Moths and Pitch Moths Dioryctria spp. and Vespamima spp.
Bark moths and pitch moths have Pitch moth attacks appear as large, similar habits and effects on trees. ugly masses of pitch that form at the Pinyon pine is the primary host in wound site. Bark moth attacks New Mexico, although ponderosa typically produce less pitch. pine and occasionally Douglas-fir and the true firs are attacked. Larger branches, limbs, and trunks of young trees are attacked. Repeated attacks can seriously weaken trees and kill branches. The most severe damage is to trees under 20 feet, especially in urban areas. The insects are rarely a problem on larger trees or in the forest environment. Pitch moth attack on the underside of pinyon branch.
BIOLOGY: Pitch moths (Vespamima spp.) require two years for one generation and overwinter as larvae each winter. Bark moths (Dioryctria spp.) require only one year for a generation and overwinter as eggs or larvae. Eggs are laid in bark crevices or near mechanical wounds on the bark. Newly hatched larvae tunnel under the bark, forming irregular galleries or elongated gouges in the sapwood. Pitch moth larvae feed on pitch the tree produces in response to their tunneling. Oozing pitch masses 1 to 3 inches {25-75mm} in diameter cover entry holes and conceal larvae and their destructive tunneling. Full-grown larvae are 3/4 to 1 inch {15-25mm} long, dirty white, yellow, orange, light green, or light brown. Bark moth larvae Fresh pitch moth attack on pinyon. feed on the inner bark and when full-grown, are marked with rows of dark spots.
24 CONTROL: No insecticides are registered for use on these insects. The only effective control is removing larvae from the pitch mass or from under the bark with a knife or similar tool. Avoid pruning or mechanical injury to the bark during the summer months when adult moths are seeking egg Bark moth larva mining under laying sites . ponderosa pine bark.
25 Twig Beetles Pityophthorus spp., Pityogenes spp.
Twig beetles are frequent pests of pines and occasionally spruce and other conifers. In forests, they attack shaded-out and storm-damaged twigs and branches. Occasionally, high beetle populations develop in drought-stressed, injured, or recently felled trees. Generally, breeding is restricted to twigs and small branches, but larger Twig beetle damage to pinyon tips. branches and thin barked portions of the trunk of stressed trees may be attacked. In Trees attacked by twig beetles can urban areas, recently transplanted be identified by fading branches pines may be killed by trunk throughout the crown. Tan sawdust infestations. is produced around the attack site. On smaller twigs and branches, most of the cambium will have been mined beneath the bark. Small, star-shaped egg galleries can be seen under the bark on larger branches and small trunks.
BIOLOGY: Adult twig beetles are 1/16 to 1/8 inch (1.5 to 3.0mm) long and dark brown. Most species have rounded rear ends but a few have a pair of short spines. The larvae are fat, white, "C"-shaped grubs with light brown heads. Most species have 2 to 4 generations per year, depending on local conditions.
CONTROL: Control infestations of twig beetles by hand-pruning infested twigs and branches and by keeping trees vigorous with Tiny exit holes on pine twigs and supplemental food and water. branches.
26 Bark Beetles Ips spp. Dendroctonus spp.
Ips beetles, also called engraver beetles, attack ponderosa and pinyon pines as well as other conifers. Dendroctonus beetles attack medium to large ponderosa pine, blue spruce, Engelmann spruce, and Douglas-fir trees in New Mexico. Different species within the genera are difficult to
Ips adult.
Full-grown bark beetTe larvae and pupae. Note blue stain to wood caused by introduced fungus.
Oendroctonus adult. distinguish based on body shape alone. Host species attacked, location, and shape of tunnels (egg galleries) they excavate are all important clues in identifying the pest species.
BIOLOGY: Details of the life cycle vary with each species but some generalizations can be made. Initial attack on a tree is made by a few adult beetles. Once a tree is selected, the beetles produce an "aggregation" pheromone, drawing many beetles to the tree. The attack on the tree may be initiated by the male (ie. Ips spp.)
27 or by the female (ie. Oendroctonu5 spp.) beetle. The beetle chews through the bark and excavates a chamber in the moist tissue beneath the bark. The opposite sex then enters the chamber and mating occurs. The female beetles then excavate distinctive tunnels or egg galleries under the bark. Eggs are laid in niches along the lateral walls.
Boring dust at the base of a tree.
Ips gallery showing central mating chamber and radiating egg galleries.
Adult beetles may introduce a number of microorganisms to the tree when they attack. Some species have evolved specialized pockets for carrying such microorganisms as fungi, yeasts, and bacteria. Introduced blue-stain fungi are particularly important in killing the tree and may provide nutrition for the developing brood. Pitch tubes from Dendroctonus beetles on ponderosa pine.
28 After hatching, larvae bore away from the egg gallery at right angles. They molt three or four times and then construct a pupal cell either in the phloem or in the bark.
Bark beetles usually attack severely weakened or damaged mature or overmature trees. Trees damaged by lightning or harsh weather and trees stressed from transplanting, logging slash, and recently cut firewood are prime candidates for bark beetle colonization. Vigorously growing trees have active Fading crowns of bark beetle infested resi n systems that deter trees. such colonization. When the beetle bores into a healthy tree, SYMPTOMS: Foliage high in the resin exudes through the wound tree begins to fade, turning from and may prevent the beetle's entry. green to yellow or red after the tree The resin may also inhibit spread of has been attacked. Boring dust, a the fungus that aids the beetles in sawdust-like material pushed out of killing the tree. When populations beetle galleries, can often be found of bark beetles are very high, around the base of the tree, in bark particularly around an outbreak, crevices beneath entrance holes, trees may be attacked by so many and on tops of branches where they beetles that even healthy trees intersect the trunk. Globules of succumb. resin called "pitch tubes", produced as the tree's defense, mayor may Time between generations varies not be present. Woodpecker considerably for different species of activity on the trunk is also a good indication that the tree has been bark beetles. Some species of Ips attacked. can complete their life cycle in six to eight weeks during warm summer months. Others require two years PREVENTION AND CONTROL: for a single generation, such as the Once a tree has been successfully spruce beetle (Dendroctonus colonized by bark beetles, it cannot rufipennis Kirby), which lives at be saved. Infested trees should be high elevations. Most species will removed, burned, or buried as soon have one or two generations per as possible to protect surrounding year. trees from attack by emerging beetles.
29 Check green fi rewood for bark beetles. Bark beetles emerging from infested firewood account for many tree losses near homes and in urban settings. If firewood has been stored for at least one season, the beetles won't be present. Green firewood collected or Green firewood piles are often bark purchased in beetle breeding grounds. summer when temperatures are high should be 160 degrees (Fl. After two or three stacked in direct sunlight and weeks of sunny weather, the beetles covered with clear plastic. Don't should all be dead. Bark beetles can use black or other opaque plastic also be prevented or controlled in because it prevents sunlight from firewood by peeling off the bark. This entering. Piles should be no larger exposes the phloem, rendering it than 4x4x4 ft. or 1/2 cord. The useless to the beetles. The method is edges of the plastic should be difficult but effective. buried in the ground. This creates a greenhouse effect, raising Preventive control measures using temperatures under the plastic up to chemicals are discussed on page 48.
Green firewood should be stacked in the sun and covered with clear plastic. 30 Roundheaded and Flatheaded Wood Borers Family Cerambycidae Family Buprestidae
Roundheaded and flatheaded wood borers attack recently dead and dying trees, often riddling them with tunnels. In the forest, they become especially numerous after fires. Roundheaded borers are often the most destructive, tunneling deep into the wood. Fresh-cut logs left in the forest or in storage for a year can be seriously damaged. These beetle larvae can often be heard chewing in infested firewood or Adult roundheaded borer, a long-horned vigas. Adults feed on cambium of beetle. twigs and small branches and on needle bases. Shoot tips occasionally flag above adult roundheaded larvae are legless, feeding sites. Adult feeding damage with cylindrical, segmented bodies. can be heavy along edges of recent Flatheaded larvae are similar but are clearcuts, in groups of seed trees left broad and flat behind the head. in clearcuts, or in residual blocks of They pupate at the end of a tunnel timber left in harvested areas. beneath the bark. Adults emerge through circular (round headed) or BIOLOGY: Generally, the life cycle oval (flatheaded) holes cut in the is complete in at least two years. bark and feed on needles and Eggs are laid in slits in the bark tender bark of twigs. throughout the summer. Young larvae feed on wood beneath the CONTROL: Wood borer damage to bark, creating tunnels filled with logs cut for lumber or vigas can be frass and wood chips. In late prevented by using wood soon after summer, they tunnel deeper into the cutting it. Other guidelines for wood and overwinter. The next preventing damage are as follows: year they continue tunneling through the wood. Full-grown • Before spring, remove wood cut in the winter from the stand. • When storing wood in the forest, piles should be as large as practical and a long distance from cutting areas. • Wood cut in summer should be used immediately. • Wood stored in the forest in summer should not be stored in the mill woodyard. • Wood piles in the woodyard should be as large as possible. Cross-section of borer infested log.
31 Western Cedar Borer Trachykele blondeli Marseul
Western cedar borer is an BIOLOGY: Adults range from 1/4 to aggressive pest of juniper and 1/2 inch (11 to 17mm) long and are Arizona cypress in New Mexico. It bright emerald with several dark belongs to the buprestid beetle areas on the wing covers. Females group also known as metallic or lay eggs under bark scales on flatheaded wood borers. Unlike branches of living trees. Flatheaded most other buprestids, the western larvae bore from branches into the cedar borer will attack and seriously main bole. They feed primarily in injure or kill seemingly healthy the heartwood for several years. trees. Considerable damage is Full-grown larvae move near the found in some juniper stands; older, surface and pupate. Adults emerge larger trees appear to be favored by in the spring, leaving oval or the beetles. Larval galleries degrade rectangular exit holes in the tree. lumber from logs, making them useless for products requiring sound CONTROL: No practical controls wood, such as furniture. or preventive measures have been developed for this insect pest.
Adult exit hole.
Cross-section of damage.
32 Juniper Twig Pruner Sty/oxus bie%r (Champlain and Knull)
Juniper twig pruner causes twig dieback on junipers and Arizona cypress growing throughout New Mexico. The insect is a small cerambycid or long-horned beetle.
BIOLOGY: The juniper twig pruner adult is 1/4 to 1/2 inch (7 to 11 mm) long and has a reddish-orange head and brownish to black body. Eggs are laid on branches, often near an intersection of twigs, one to two Adult exit hole. feet from the branch tip. Larvae are small, white, cylindrical, legless grubs that kill twigs by boring through the centers. The life cycle may take as long as two years to complete.
CONTROL: No chemicals are registered for control of this pest. Damage can be unsightly when populations are high but trees are rarely seriously injured by the juniper twig pruner.
Cross section of injured twig.
juniper twig pruner damage.
33 Mistletoes Arceuthobium spp. and Phoradendron spp.
Mistletoes are parasitic plants that nearly a foot long on ponderosa injure and may eventually kill their pine. True mistletoe plants vary in woody hosts by stealing water and length from a few inches to several essential nutrients. Both dwarf feet. Symptoms of mistletoe mistletoe and true mistletoes occur infection include swelling at in New Mexico. Dwarf mistletoes infection sites and formation of live only on conifers, while true witches' brooms. mistletoes occur on conifer and hardwood trees and shrubs. In New BIOLOGY: Dwarf mistletoes spread Mexico, dwarf mistletoes attack by shooting seeds from explosive ponderosa pine, Southwestern berries a distance of 20 to 30 feet. white pine, pinyon, Douglas-fir, True mistletoes are spread by birds Englemann spruce, and blue spruce, that eat mistletoe berries. Seeds pass while true mistletoes are found on through the birds unharmed and are several species of juniper, numerous spread in their feces . species of oak, and other hardwoods. CONTROL: Branch infections on trees attacked by mistletoe can be Mistletoe plants vary in color from pruned out to reduce damage and yellow to green to red-green. Dwarf to reduce further spread of the mistletoe plants vary in size from an parasite. If the infection is on or inconspicuous bud structure close to the trunk of the tree, it protruding through the tree bark as cannot be removed. found on Douglas-fir to shoots
Witches broom caused by dwarf mistletoe.
34 In dwarf mistletoe infested forests, underplanted with other tree favor non-host trees to leave when species. Young regeneration can be removing trees from the site. protected from infection by Infested stands can also be removing older infected trees.
Infection on trunk.
True mistletoe on juniper.
35 White Pine Blister Rust Cronartium ribicola
White pine blister rust is a disease time of infection, almost 100 percent of white pines that was introduced humidity is necessary for the fungus to North America by the early to successfully invade a tree. The 1900's. The disease has devastated fungus enters through stomata on the forests of eastern white pine, needles and grows slowely to the western white pine, sugar pine and stem where it eventually forms a swollen canker. Several years after whitebark pine in other parts of the infection, the canker will produce continent. The disease was spores that infect Ribes leaves. The discovered on Southwestern white canker on pines is perennial and the pine in the Sacramento Mountains stem is eventually girdled and killed. of southern New Mexico in 1990. Trees die when the main stem It appears that a high percentage of becomes infected from attached this native tree may be killed by this branches. On small trees, trunk disease over the next few decades. infection usually occurs directly from Also, the disease has the potential needles. to infect limber pine which occurs in mountain forests Statewide and bristlecone pine which is found at high elevations in the Sangre De Cristo mountains in the northern portion of the State.
BIOLOGY: White pine blister rust requires the presence of currant or gooseberry shrubs (genus Ribes) to complete its life cycle. Five different types of spores are produced through the year: three Spores on Ribes on Ribes and two on pines. In the . late summer or fall, spores produced on Ribes leaves are CONTROL: No effective controls windblown to pine needles. At the are available to stop the spread of the disease in the Sacramento Mountains of southern New Mexico. Also, once a forest tree is infected, little can be done to save it. For ornamental trees, pruning branches with cankers that are at least six inches from the main stem may prolong the life of the tree. It appears that some Southwestern white pines may be resistant to the disease, but it will take many years to confirm this observation. To avoid spread of the disease, white pines and Ribes Stem shrubs from the Sacramento canker with Mountains should not be blisters. transplanted elsewhere in the State.
36 Gymnosporangium Stem Rusts of Junipers Cymnosprangium spp.
Several species of stem rusts occur Albuquerque area. This rust can in New Mexico on junipers. All cause significant damage to apple produce orange to brown fruiting trees. structures or spore sacs that gelatinize during spring rains. BIOLOGY: Most Cymnosporangium Swellings, distortions, and witches rusts require two hosts to complete brooms often occur on junipers, but their life cycle. The gelatinious alternate host plants can be more structures are produced following seriously affected by these fungi. C. spring or summer rains and they bethelii causes knobby galls or produce spores that infect the tapered swellings, and the alternate alternate host. Yellow to orange host are hawthorns (Crataegus spp.). lesions occur on the alternate host C. nelsonii causes globe-shaped and they produce another type of galls on juniper and has alternate spore that are dispursed by the wind host species in the genus to junipers where infection causes Amelanchier or service-berry. C. galls or swellings. The fungus speciosum causes tapered swellings overwinters on junipers. on woody tissue and is the showiest of the various species due to the CONTROL: Other than branch red-orange structures. Its alternate dieback, the native species of hosts include plants in the genera Cymnosporangium in New Mexico Fendlera and Ph ila delph us. C. cause little damage to junipe rs and bermudianum does not require an their alternate hosts and control is alternate host and C. multiporum usually unwarranted. However, probably does not require more fungicides have shown to be than one host. An eastern species, effective against the cedar-apple the cedar-apple rust, C. juniperi rust to protect apple crops. virginiana, has been found in the
Gelatinous fruiting structure.
37 Broom Rusts Chrysomyxa arctostaphyli Me/ampsore/la caryophy/lacearum
Broom rusts are primarily a forest successfully spread. Kinnikinnick is problem. Infections cause growth the alternate host for spruce broom loss, top-kill, and occasionally tree rust and chickweed the alternate mortality. Trunk infections may host for fir broom rust. Needles on provide entrance for decay fungi. brooms are often stunted and drop off each fall. Other fungi and Two species of broom rust are disease organisms may cause important in New Mexico-spruce formation of witches' brooms, but broom rust, which attacks only broom rust causes annual drop Engelmann spruce and blue spruce, of needles. and fir broom rust, which attacks white fir and subalpine fir. CONTROL: On trees with only a Infections are characterized by few branch infections, witches' conspicuous, dense masses of brooms can be pruned out if the branches called witches' brooms. infection is not too close to the Witches' brooms are large and trunk of the tree. Trunk infections yellow. are characterized by trunk swelling and cracks in the bark at infection BIOLOGY: Broom rust fungi sites. There are no chemical or require the presence of an alternate biological controls available for host to complete their life cycle and broom rust.
Broom rusl on while fir.
38 Branch and Shoot Dieback on Spruce Cytospora Canker of Spruce Cytospora kunzei SacCo
Sirococcus Shoot Blight of Spruce Sirococcus strobilinus
Cytospora canker and Sirococcus BIOLOGY: Tiny black fruiting shoot blight are primarily fungal bodies of Cytospora canker can be diseases of Colorado blue spruce, seen by scraping away bark in the although other ornamental spruce transition area of diseased and and Douglas-fir may be attacked. healthy tissue. Spores ooze from fruiting bodies in wet spring and Cytospora canker causes death of summer weather and spread to the lower branches followed by same or other trees by splashing progressive dying of branches up rain, wind, insects, birds, and man. the tree. Trees are occasionally Spores must land on freshly killed, but more often damaged by wounded wood to infect the tree. loss of symmetry. Cytospora cankers are inconspicuous and may Small fruiting structures of or may not cause bark deformation. Sirococcus shoot blight can be seen Any part of the branch is susceptible with a hand lens on bud scales and to girdling except for very small other parts of dying shoots. A twigs. Typically infected areas are canker also forms as the fungus marked by a heavy, clear amber grows within the succulent stem; it pitch flow that later dries and covers rarely invades older wood. Spores the cankered area with a hard, are produced by fruiting structures crusty, white pitch coat. Pitch during wet periods and are spread exuded will also drip down and by splashing rain and irrigation cover branches below the infection. water. Needles on infected branches fade and eventually turn brown. CONTROL: Trees under Needles may stay on the branch for environmental stress, especially up to a year after infection. during drought, appear most susceptible to infection. Fertilizing Sirococcus shoot blight is indicated and watering during dry periods by fading, drying needles at the aids tree vigor, but will probably not ends of branches. Needles control the disease. eventually drop, leaving the last 2 to 12 inches of branches bare by summer's end. It is usually seen after heavy rainfall and high humidity.
39 Cytospora-Early detection and Sirococcus-Remove diseased removal of infected branches can shoots to reduce sources of reduce continued development of infection and improve the tree's the disease. Prune infected appea rance. Fungicide sprays may branches close to the trun k. help reduce infection if applied Cankers will continue to produce before sum mer rains and periods of spores even after pruning so hi gh humidity. See page 48 for promptly destroy (burn of bury) cut specific recommendations. branches. Prune only in dry weather to avoid spreading spores to healthy branches. After pruning, watch for development of new ca nkers. No chem ica l sprays adequately control Cytospora on spruce.
40 Root Rots Shoestring Root Rot Armi/faria sp.
Annosus Root Rot Heterobasidion annosum
Root diseases are difficult to distances by means of spores or diagnose since symptoms above the locally by rhizomorphs. When the ground can resemble symptoms fungus contacts the tree's root or caused by many other problems. In root collar, it penetrates the bark ornamental situations, root and enters the living tissue. It then problems frequently develop in spreads and penetrates the wood. response to unfavorable soil Cellulose is consumed, leaving the conditions, such as an impenetrable root light-colored and causing the hardpan or abnormally high or low tree's butt to rot. In late summer or moisture content. In forests, two early fall, a honey-colored frequently encountered root mushroom is produced, commonly diseases are shoestring root rot and at the base of the infected tree. As annosus root rot. Both of these the mushroom matures, the surface diseases occur in expanding of the cap breaks into dark brown pockets, often with mortality at the scales. Whitish gills produce wind center. The entire crown of infected borne spores. saplings usually turns reddish brown all at once. Dieback, Annosus root rot causes small silver thinning foliage, or yellowing of the flecks to form on the cambium of crown is characteristic in older the roots and root collar. It trees. Forest trees are predisposed produces long, shallow pockets of to root disease when stressed by decay, often surrounded by spongy fire, drought, poor sites, or insect wood. Root rot may penetrate the injury. heartwood and grow into the stem, resulting in butt rot. It's spread by Both diseases attack a wide range of airborne spores that often infect conifers. Shoestring root rot infects freshly cut stumps or locally from both hardwoods and conifers, contact between healthy and although conifers are more infected roots in the soil. The vulnerable to mortality. Young fungus produces small (less than 1 pines planted on old hardwood sites in.), white to buff-colored conks are often infected by this disease under the bark or larger (6 - 8 in.) because the fungus remains active shelf-like conks flat against the soil in stumps and old root systems for or in litter. years. CONTROL: Maintain trees in BIOLOGY: Shoestring root rot often vigorous condition. Avoid planting produces white, fan-shaped mats pines on old hardwood sites that beneath the bark on the lower contain shoestring root rot infected surface of infected boles and stumps. In areas infected with shoestring-like black rhizomorphs in annosus root rot, avoid thinning the soil. Outer bark at the root stands during cool, wet periods, that collar is often covered with resin. stimulate spore production. The disease spreads over long
41 Needle Diseases
In New Mexico, relatively dry bottoms of deep arroyos, sapling conditions help limit the incidence thickets, and on low branches on of foliage diseases in conifers. north sides of trees pole-sized and Many non-insect foliage problems larger. are due to environmental factors rather than disease. However, there Dothistroma pini-Dothistroma are a few needle diseases that may needle cast (red band disease or red occur. banded needle blight) may infect ponderosa, pinyon, and Austrian Lophoderme/la spp.-This fungus is pines in New Mexico. Symptoms an occasional problem primarily for first appear as yellow or tan bands ponderosa pine in New Mexico at around the needles. Bands later elevations above 7,000 feet. turn red . Both old and new needles During outbreaks of the disease, may be infected, but infection nearly all of the second-year foliage periods differ. Old needles are in the lower half of the crown may infected in spring and usually turn be lost. If conditions allow for brown by fall. New needles are successive years of infection, only infected in mid-summer and turn the current year's needles will be brown in late summer the following left on the tree. Airborne spores of year. Initial infection occurs on the the fungus settle and germinate on lower portion of the tree and developing needles in spring. The progresses upwards. Spores are following spring, infected needles released during rainy weather and turn reddish brown and small, spread by splashing rain. fruiting structures develop that are difficult to detect. Needles dry and Rhabdocline pseudotsugae fall from the tree shortly after the Rhabdocline needle cast on fruiting structures mature. Douglas-fir is an occasional problem in New Mexico. The most f/ytroderma deformans- recent outbreak was seen in 1989 in Elytroderma needle cast is and around the Lincoln National widespread and infects pinyon and Forest and on Mescalero Apache ponderosa pine in New Mexico. It lands. This conspicuous fungus is particularly damaging because it disease causes mottling and invades twigs and branches and premature shedding of needles over persists for several years. Symptoms a year old. It occurs during long, occur in spring when all of the year rainy periods while new needles are old needles on an infected twig growing. The disease is not usually simultaneously turn red brown 6- serious since conditions favoring 1 2mm from the needle bases. infection rarely occur over Infected needles persist on the tree successive years. until fall or winter. Fortunately, incidence of the disease is low because weather conditions favoring its development are rare. Local outbreaks generally start in sheltered humid places, such as
42 Other Problems
Numerous environmental stresses, both natural and human-caused, may injure or kill trees. Any factor interfering with the tree's physiology can injure it.
Natural Environmental Stresses Cold Injury-lnjury from cold Water Injury-lack of water can temperatures can usually be cause foliage to dry from the tips categorized as frost damage or back and eventually foliage and winter damage. Frost damage most twigs may die. Drought injury is often occurs in the spring after indicated when foliage yellows or shoots have begun to grow. Trees browns and needles are prematurely most frequently injured are those cast. Flooding or a dramatic growing at the northern limit of their increase in the water table can species range. Young conifers are suffocate tree roots, resulting in more susceptible to injury than are above-ground symptoms of older trees. Frost damage to spring discolored foliage and spongy bark. shoots may resemble damage from shoot borers such as pine tip moth. Soil Deficiencies-A shortage of Winter injury generally occurs in available nutrients can injure or kill midwinter to early spring. Most conifers. New Mexico soils are often, the entire tree above the often deficient in iron and zinc and snow line is affected. Cold winds have a pH level that ties up many dry the foliage but because the nutrients in compounds the tree ground is frozen, the tree can't can't use. Nutrient abnormalities replace lost moisture so foliage dies are indicated by foliage and turns red. Protect ornamental discoloration and often by distorted conifers by covering them or needles and twigs. Heavy clays buffering them from dry, cold commonly encountered in New winds. Mexico are difficult for roots to penetrate and can significantly limit Heat Injury-Tree tissues may be tree growth. injured by unusually high temperatures. Sunscald results from Storm Injury-High winds can overheating and drying of bark and break branches, limbs, or trunks. is characterized by reddening bark, Shallow rooted trees are often followed by canker formation. Leaf uprooted. Heavy snows may break scorch or needle scorch, a heat limbs. Hailstorms can wound or kill injury found more frequently on buds, foliage, twigs, and branches. hardwoods but also on young Damage varies with time of year, conifers, results when a tree loses size of hailstones, and intensity of more water through transpiration the storm. Younger stems with than it can absorb through the roots. tender bark and trees with developing foliage are most seriously damaged.
43 Animallnjury-Mice and other and kill trees. These birds drill small rodents seriously damage holes, often in a characteristic trees by feeding on bark at the root pattern, and drink the sap. Bark in collar of young conifers, particularly heavily drilled areas may die. in plantations. Damage usually Occasionally, the tree or its top is occurs in winter when snows are completely girdled. Forest trees deep, food scarce, and where there may be browsed on by deer and is plenty of grass or weed cover damaged by deer or elk rubbing around the trees' base. Trees are antlers against tender bark. Small often completely girdled although ornamental trees and shrubs around symptoms of injury may not appear the home may be injured by dog until the following summer or fall. urine and by cats sharpening their Sapsuckers also commonly injure claws on thin bark.
Human-Caused Stresses Soil Compaction-Soil trampled by lightning. Industrial emissions such confined animals or compacted by as sulfur dioxide and fluorides, machine traffic is less aerated and usually only cause injury in areas resists water penetration and immediately downwind of the drainage. Injury to tree roots during pollution generator. soil compaction results in yellowing foliage, premature leaf drop, and Salt Injury-De-icing salt applied to often death of the tree. roads, walks, and driveways can seriously injure trees . Most of the Mechanicallnjury-frequent damage occurs on foliage but wounding' of ornamental trees eventually roots may be killed. Salt occurs from lawn mowers and injured trees may have yellow, red, or trimmers hitting the base of the tree. brown needles. Frequently, only the Mechanical injuries can occur from road side of the tree shows symptoms anything scraping against the bark. resulting from salt spray from passing Poor pruning jobs can seriously vehicles. Calcium-based salts are less wound trees. Excavation around damaging than sodium salts; trees can hurt the root system . unfortunately these are infrequently used. Salt-injured trees also appear Air pollution-Trees can be injured more susceptible to winter injury. or even killed by air pollutants. Symptoms of air pollution injury Herbicide Iniury~onifers are very generally include discolored, susceptible to herbicides and spotted, or blotched foliage. Most herbicide drift. The concentration damaging pollutants are produced and type of herbicide reaching the from industrial emissions and tree, the type of tree, and weather vehicle exhausts. Oxidants conditions all affect severity of injury. produced by internal combustion Frequently, foliage and twigs will be engines are concentrated in urban distorted. Ornamental trees can be areas but may be windborne to rural damaged by overapplication of lawn areas. Ozone injury may occur weed killers, which usually contain anywhere from ozone created by 2,4-D.
44 General Pesticide Recommendations and Precautions
Mechanical and biological options have been provided for reducing pest damage wherever possible. The use of insecticides is rarely necessary in forests where individual tree injury or loss is often insignificant. However, it may be necessary to use pesticides to protect valuable ornamental trees, nursery stock, or forest trees in areas heavily traveled. The nature of pesticides mandates strict adherence to recommended dosages and precautions for handling and use as listed on the label. Follow these precautions ·whenever using pesticides:
1. Read the entire label before 9. Wear protective clothing and using product. masks when directed on the label. 2. Observe all precautions each 10. Bathe and change to clean time you use a material. clothing immediately after spraying or dusting. Wash clothing before 3. Store pesticides under lock and reuse. key, out of the reach of children and pets, and away from food and 11. If pesticides are spilled on the feed. skin or clothing, change clothing immediately and wash thoroughly. 4. Keep pesticides in their original conta i ners. 12. If illness develops during or after spraying or dusting, call a 5. Dispose of unused pesticides physician immediately or take the and containers in such a way that patient to a hospital. they are no longer hazardous. 13. Avoid pesticide injury to plants; 6. Follow directions pertaining to use separate equipment for residual tolerances on edible plants; herbicides and insecticides. allow the specified time interval between last application and 14. Rates of application have been harvest. carefully computed; don't use more than recommended. 7. Use pesticides only on plants specified and at the correct rate and 15. Don't spray or dust on a windy schedule. day; avoid drift that would injure plants on adjacent property. 8. Do not eat or smoke while applying pesticides.
45 Pesticides used improperly can be injurious to human beings, animals, and plants. Follow the directions and heed all precautions on labels. Store pesticides in original containers under lock and keY- Apply pesticides so that they do not endanger humans, livestock, crops, beneficial insects, fish, and wildlife. Do not apply pesticides where there is danger of drift when honey bees or other pollinating insects are visiting plants, or in ways that may contaminate water or leave illegal residues. Avoid prolonged inhalation of pesticide sprays or dusts; wear protective clothing and equipment, if specified on the label. If your hands become contaminated with a pesticide, do not eat or drink until you have washed. In case a pesticide is swallowed or gets in the eyes, follow the first aid treatment given on the label, and get prompt medical attention. If a pesticide is spilled on your skin or clothing, remove clothing immediately and wash skin thoroughly. NOTE: Some states have restrictions on the use of certain pesticides. Check your State and local regulations. Also, because registrations of pesticides are under constant review by the U.S. Environmental Protection Agency, consult your local forest pathologist, county agriculture agent, or State extension specialist to be sure the intended use is still registered. 46 Generalized Pesticide Control Strategies for Conifer Pests in New Mexico Scales-Spray trees with "dormant" most caterpillar and sawfly or "superior" oil before buds break problems. Bacillus thuringiensis to kill overwintering immature (Dipel Insecticide sprays are only effective Conifer Aphids-It's usually against the "crawler" stage of scale unnecessary to control aphids on insects. Repeat applications are conifers. If control is desired, spray usually required at seven- to 10-day trees with a dormant oil before buds intervals to maintain coverage as break. (See "scales.") Insecticidal eggs hatch. Insecticides with soap, acephate (Orthene), diazinon, labeling for scale insects include dimethoate (Cygon), endosulfan, acephate (Orthene 47 Bark Beetles-Once bark beetles Borers-Insecticide treatments are have invaded a tree, it cannot be ineffective against borers once they saved. Trees at high risk can be hatch and burrow under bark. protected from attack by spraying Conifers infested with borers are the trunk and large branches with a usually dead or dying from other 2% carbaryl (Sevin) suspension. causes. Chlorpyrifos (Dursban) has This will kill the adult beetles as some labeling for borer prevention. they chew through bark to enter the tree. Sirococcus Shoot Blight Fungicides that may help prevent Some labeling for bark beetles Sirococcus shoot blight include (preventative) is present on the Daconil and mancozeb (Dithane chlorpyrifos (Dursban, and Manzate<8> 200). The use of trade or firm names in this publication is for reader information and does not imply endorsement b y the U.S. Department of Agriculture of any product or service. 48 References Baker, J. R. (Ed.) 1980. Insects and Cranshaw, W. S., and D. A. related pests of shrubs . North Leatherman. 1986. Pine Carolina State Univ. Coop. needle scale: characteristics Ext. ServoPub . AG-189. 199 and control on evergreens. pp. Ibid. 5514 2 pp. Beatty, J. S. 1986. Forest insect and English, L. M . 1985. Home and disease field guide. USDA garden insect control guide. Forest Service Southwestern NMSU Coop. Ext. Servo Region R3-TP-1 . Guide 400 J-16.50 pp. Benyus, J. M . (Ed.) 1983. Christmas Furniss, R. L. , and V. M . Carolin. tree pest manual. USDA, 1977. Western Forest Insects. Forest Servo North Central USDA Forest Servo Mise. Experiment Station. 108 pp. Pub. 1339. 654 pp. Brookes, M., R. W . Stark, and R. W. Gates, D. E., H. L. Brooks, and H. Campbell (Ed.). 1978. The E. Thompson . 1982. Insect Douglas-fir tussock moth: a and mite control on shade synthesis. USDA Forest Serv o trees and woody ornamentals. Tech. Bull. 1585. 331 pp. Kansas State Univ. Coop. Ext. Servo Pub. No. C-586. 20 pp. Bohmont, B L. 1983. The new pesticide user's guide. Reston Hamman, P. J., and G. Mcliveen. Publishing Co., Inc. Reston, 1983. Destructive mites in VA. 452 pp. the garden and home landscape. Texas Agric. Ext. Coulson, R. N., and J. A. Witter Servo Leaflet L-1244. 6 pp. 1984. Forest Entomology, Ecology, and Management. Hartsbarger, W. M . 1979. Spider John Wiley and Sons, Inc. mites: characteristics and New York, NY 669 pp. control. Colorado State Univ. Coop. Ext. Servo Cranshaw, W. S. 1987. Cooley Service in Action Series No. spruce galls: characteristics 5.507. 2 pp. and control. Colorado State Univ. Coop. Ext. Ser., Ft. Hepting, G. H. 1971. Diseases of Collins. Service in Action forest and shade trees of the Series No. 5.534. 2 pp. United States . USDA Forest Service. Agrie. Handbk. No Cranshaw, W. S. 1988. Landscape 386. 658 pp. insect and mite pest management guide. Ibid. XCM-38, 50 pp. 49 Johnson, W. T., and H. H. Lyon. Parker, D.L., 1991, Integrated Pest 1988. Insects that feed on Management Guide, Arizona trees and shrubs. Cornell Five-Spined Ips, Ips Lecontei Univ. Press, Ithaca, NY. 556 Swaine, and Pine Engraver, pp. Ips pini (say), in Ponderosa Pine. USDA Forest Service, McCambridge, W . F. 1974. Pinyon Southwestern Region, R-3 91- needle scale. USDA, Forest 8.17 pp. Service, Forest Pest Leaflet 148. 4 pp. Rifle, J. W., and G. W . Peterson. 1986. Diseases of trees in the Miller, R. L., and D. J. Nielsen. Great Plains. USDA Forest 1987. Insect and mite control Service, General Technical on woody ornamentals and Report RM-129. 149 pp. herbaceous perennials. Ohio State Univ. Coop. Ext. Servo Stephens, R. E., and W . F. Bull. 504. 107 pp. McCambridge. 1978. Protect your pines from mountain New Mexico Department of pine beetles. USDA Forest Agriculture, Forest Service Service. Pamphlet No. 779- USDA, N.M. Dept. of State 324. 20 pp. Forestry, and N.M. Coop. Ext. Serv.-USDA. 1977. Insects and diseases of evergreens in New Mexico. U.S. Gov. Print. Off., Washington, D.C. 21 pp . 50 The U.S. Department of Agriculture (USDA) prohibits discrimina tion in all its programs and activities on the basis of race, color, national origin, gender, religion, age, disability, political beliefs, sexual orientation, and marital or family status. (Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA's TAR GET Center at 202-720-2600 (voice and TIY). To file a complaintof discrimination, write USDA, Director, Office of Civil Rights, Room 326-W, Whitten Building, 14th and Inde pendence Avenue, SW, Washington, DC 20250-941 0 oreal! 202- 720-5964 (voice or TIY). USDA is an equal opportunity provider and employer.