SEQUOIA PITCH MOTH

Integrated Pest Management for Home Gardeners and Landscape Professionals

The sequoia pitch moth, Synanthedon rarely kills trees. Larval feeding some- sequoiae, occurs from California north times causes one or more limbs to die or through British Columbia. This clear- become weak enough to break, espe- wing moth (family Sesiidae) infests cially if infested trees are young. Pines most conifer species, including Douglas with pruning wounds or other injuries fir, pines, and spruces. In California it are more frequently attacked than unin- most often attacks pines, especially jured pines. Damage is prevalent in those in urban coastal areas of northern certain pines planted in landscapes, California, from Monterey Bay to the such as Monterey pine (Table 1). San Francisco Bay Area. A similar clear- wing species, the Douglas-fir pitch IDENTIFICATION moth (Synanthedon novaroensis), infests Infestations are recognizable by the Douglas fir, pines, and spruces from gray, pink, reddish, or yellowish pitch northern California to Alaska. masses that protrude from infested trunks and limbs. Pitch masses initially DAMAGE are small, soft, glistening, and reddish Figure 1. Differences in appearance of a bark beetle pitch tube (left) and a Sequoia pitch moth is primarily an aes- brown to pink. As the larva feeds and sequoia pitch moth pitch mass. Bark thetic pest. The main effect of larval grows beneath each mass, the gummy beetle pitch tubes have a distinct round feeding is to cause infested pines to exudate enlarges, hardens, and becomes hole in their center, whereas the pitch produce copious amounts of unsightly darker gray. A brownish pupal case mass of the sequoia pitch moth often resin. Sequoia pitch moth larvae cause may protrude from the mass after the lacks a distinct emergence hole. very little injury to cambium and wood. larva has matured and emerged as an This relatively minor damage does not adult. Old pitch masses can remain on masses are often reinfested because egg- usually cause girdling of the trunk and bark for several years. Abandoned pitch laying females are attracted to these in- jury sites.

Table 1. Relative Susceptibility of Pines (Pinus spp.) to Sequoia Pitch Moth. People unfamiliar with the damage sometimes confuse pitch moth pitch COMMON NAME SCIENTIFIC NAME masses with bark beetle pitch tubes MOST SUSCEPTIBLE (Fig. 1). Bark beetle pitch tubes are usu- Afghan, Allepo, Brutia, Calabrian, P. brutia, P. eldarica, P. halepensis ally less than 1⁄2 inch in diameter and Mondel, Turkish, and others1 typically have a distinct round hole in Bishop P. muricata the center made by an adult beetle. Bark Japanese black P. thunbergiana beetle pitch tubes often resemble the end Mexican P. patula Monterey P. radiata of a large gummy drinking straw pro- Ponderosa P. ponderosa truding from bark. Sequoia pitch moth Shore or Beach P. contorta masses are much larger and vary in shape from roundish to elongate oval. LEAST SUSCEPTIBLE Canary Island P. canariensis Italian stone P. pinea Resinous ooze from pine bark can have other causes, including Diplodia canker, Pines are more susceptible to pitch moths if pruned or otherwise injured. western gall rust, injuries such as prun- 1 Various common and scientific names are used for these closely related Asian and ing wounds, and the serious pitch canker European natives. Many species are quite susceptible, but their susceptibility varies and confusion among names makes them difficult to distinguish. disease, which is caused by the fungus Adapted from Frankie et al. 1986. Fusarium circinatum (=F. subglutinans f. sp. pini). Unlike the distinct protrusions

PEST NOTES Publication 7479 University of California Agriculture and Natural Resources Revised March 2004 March 2004 Sequoia Pitch Moth

moth biology, life history, and manage- ment are similar to those of sequoia (actual pitch moth. size) LIFE CYCLE Because not all individuals emerge (actual from pupae at the same time, adult size) moths can be present anytime from Adult Egg May through early September. Adults emerge earlier at warmer inland sites, and later at cooler sites near the coast. (actual Peak moth emergence occurs in June size) and July. Adults live only a few days, Pupa during which they mate and females lay eggs. Eggs are laid individually on bark, usually in crevices around prun- Larvae ing wounds and other injury sites. Eggs are 1⁄16 inch in diameter, reddish brown, oval, and somewhat flattened. They hatch in about 2 weeks. The dirty white, grayish, or pink larvae feed for several (actual size) months, excavating a shallow cavity that penetrates the inner bark to the Figure 2. The stages and life cycle of sequoia pitch moth. cambium surface of wood. After feed- ing, about one month is spent in the pupal stage. The dark brown pupae are caused by bark beetle pitch tubes and and Pest Notes: Pitch Canker listed in about 3⁄4 inch long and occur in silk- sequoia pitch moth pitch masses, inju- Suggested Reading. lined chambers within the pitch mass. ries, and pathogenic diseases usually Before adults emerge, the pupae force cause bark to become coated with a thin Sequoia pitch moth adults are day- about half of their length through the layer of resin resembling thick syrup. flying moths distinguished from other pitch surface, leaving a brown, paper- Bark discolors due to pitch canker; bark moths by their mostly clear wings. The like case after they emerge. Although a around beetle and pitch moth attacks is wings have bluish black margins with few individuals may complete their not discolored. Pitch canker can infect some yellow at the base. The moth’s development within a year, most se- pine tissue of any age, including young head and thorax are brownish black, quoia pitch moths require 2 years to branches and terminal shoots the diam- with some yellow. The legs are mostly develop from egg to adult (Fig. 2). The eter of a pencil; bark beetles and se- bright yellow. The abdomen is covered insect spends most of its life in the lar- quoia pitch moth primarily attack the with blackish and yellow hairs in alter- val stage. main trunk, though sometimes large nating bands, resembling that of a yel- limbs several inches in diameter can lowjacket wasp. Females are somewhat MANAGEMENT also be attacked. Yellow and red dying larger and plumper than males. Unlike Protect trees from injury. Moths prefer and dead branches scattered through- females, male clearwing moths have to lay eggs on bark near pruning out the tree are a characteristic symp- many fine hairlike projections along wounds and other injury sites. Provide tom of pitch canker, eventually their antennae. The adult’s body is trees with proper cultural care (espe- followed by death of the entire pine about 3⁄4 inch long with a wingspan of cially appropriate irrigation) to reduce tree; branches rarely die from sequoia 3⁄4 to 11⁄4 inches. Although the colors the frequency of borer attack and in- pitch moth. Depending on the species and erratic flight behavior of adults crease the trees’ ability to tolerate dam- of bark beetle and other factors affect- resemble those of paper wasps, clear- age. Carefully scrape away pitch ing tree health, branch dieback (from wing moths are not wasps and are masses to expose and kill larvae. No the red turpentine beetle) is rare, or stingless and harmless to people and other control aside from minimizing dieback appears first only at the tree pets. injuries to trees is recommended. Pines top (due to Ips beetles), or the entire tree are not seriously harmed by this insect. fades and dies (from Dendroctonus spp. The adult Douglas-fir pitch moth is and others) without being preceded by bright orange and blackish, instead of Sticky traps baited with clearwing moth scattered branch dieback. For more yellow and dark colored as with se- pheromone (sex attractant) are commer- information, see Pest Notes: Bark Beetles quoia pitch moth. Douglas-fir pitch cially available for monitoring the sum-

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mer flight period of adults. However, Keep weed trimmers and lawn mowers Physical Control such traps are primarily used to time away from trunks; for example, main- Scraping away or prying off resinous the application of insecticides, and no tain a several-foot-wide area around pitch cankers is the only direct method effective insecticides have been found trunks free of turf and other vegetation. of controlling pitch masses and larvae, for controlling sequoia pitch moth. Protect trunks from other sources of except possibly for pruning off smaller injury, such as from vehicle bumpers. branches. If resin masses are carefully Cultural Control excised, larvae or pupae can be found Small limbs infested with larvae and Plant only species that are properly and killed. Properly removing pitch pitch masses can be pruned off, but this adapted to the area. Certain pines are masses from all nearby trees, along may lead to future infestations around much less susceptible to sequoia pitch with appropriate cultural practices, can the pruning wound. If pines must be moth than others. Consider planting a reduce reinfestations and control local pruned, prune only from October more resistant species (Table 1). Learn clearwing moth populations. Inad- through January so that injuries begin to the cultural requirements of pines and equate application of pitch mass re- close before the egg-laying adults provide proper care to maintain vigor- moval technique allows the larva or emerge in spring. Prune in a way that ous growth. Appropriate irrigation is pupa to survive and mature into an enhances wound closure, such as by especially important to tree health. Inap- adult that can reinfest trees. Only one making cuts just outside the branch propriate watering is probably the most larva or pupa occurs in each pitch mass, bark ridge. common problem with landscape plants. although several adjoining masses Trees are damaged by watering too fre- sometimes merge. Unless the mass has Stake pines only if needed to protect or quently or by inadequate irrigation. become reinfested, no insect will be support the trunk or to anchor the When irrigating trees, apply water be- present in masses older than about 2 rootball during the first year or so after neath the outer canopy, not near trunks. years because the insect will have ma- planting. If the tree was rigidly staked Avoid frequent, shallow watering that is tured and emerged as an adult. in the nursery, remove the stakes and (if often used for lawns. A general recom- needed) restake the plant. Do not fasten mendation is to irrigate infrequently Each pitch mass gradually enlarges, trunks firmly; allow the main stem to (possibly once a month during drought hardens, and darkens as the larva be- flex without rubbing on stakes because periods) but with sufficient amounts so neath it matures. Learn to distinguish some movement with the wind is that the water penetrates 1 to 2 feet into newer pitch masses from older ones in needed for trunks to develop strength. the soil. This can be achieved by apply- order to recognize where the insect is Remove ties and stakes promptly when ing water slowly through drip emitters most likely to be found (Table 2). Lar- they are no longer needed, usually that run continuously for about 1 to 3 vae are easily overlooked because their within 2 years after planting. For more days. The specific amount and fre- pinkish to gray color resembles the information, see Planting Landscape Trees quency of water needed varies greatly color of pitch. Young larvae (those listed in Suggested Reading. depending on the site and tree species. found in smaller, pinkish masses)

Table 2. How to Distinguish New Pitch Masses from Older Ones and Where to Locate the Borer.

PITCH MASS APPEARANCE INSECT APPEARANCE INSECT LOCATION YOUNG PITCH MASS smaller, soft, glistening, pink to reddish larva white, pink, or yellowish with a larva usually beneath pitch mass in bark brown brownish head; larva can be as small as cavity on phloem wood; scoop inside and 1 ⁄12 inch, but pitch is usually overlooked slightly upward within cavity to remove 1 until larva is about ⁄8 inch pitch and kill the larva OLDER MASS larger (up to about 3–5 inches), larva up to about 1 inch long; body is dark larva usually in pitch mass or pupating in harder, darker grayish gray to black before forming a dark brown tunnel near surface of mass pupa ABANDONED MASS darker gray, relatively dry, often no insect present; old mass can remain an empty, brownish, papery pupal case cracked and more flattened than on bark for several years after insect may protrude from mass young masses emergence; mass may become reinfested

REINFESTED MASS abandoned mass (hard, gray, larger) Insect appearance and location vary depending on age as described above. exhibits newer pitch exuding from center, margins, or both; pitch may appear fresh (glistening, reddish brown to pink) or older (grayish) depending on age of reinfestation

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typically occur below the bark surface side of the mass or in the tree wound within a small cavity that they have and puncture or crush the larva or chewed in the inner bark. Pupae and pupa. Work carefully to avoid further older, larger larvae occur in grayish wounding of the bark. Because they are pitch masses. These older insects are harder and larger, older masses are usually found near the surface of the relatively easy to remove by prying at mass, somewhat outward from the bark several locations around their edges cavity they had created when younger. until the whole mass can be lifted off If pitch masses are simply scraped (Fig. 3). Smaller masses have a softer, away without actually locating and stickier consistency that may have to be killing or disposing of the larva or scooped out. Unless the larva is defi- pupa, the insect can survive and cause a nitely located and killed during pitch new pitch mass to develop at that site. removal, scrape slightly upward within Pupae or older larvae can survive in the bark cavity and remove as much of discarded pitch masses unless insects the pitch as possible to increase the are crushed or bagged and disposed of likelihood of killing the young larva. away from trees. REFERENCES Gently pry or scrape the pitch mass off Frankie, G. W., J. B. Fraser, and J. F. bark with a screwdriver or stiff putty Barthell. 1986. Geographic distribution knife. Locate the insect on the under- of Synanthedon sequoiae and host plant susceptibility on Monterey pine in ad- ventive and native stands in California For more information contact the University (Lepidoptera: Sesiidae). Pan-Pacific En- Figure 3. Pitch mass around a pruning of California Cooperative Extension or agri- tomologist 62:29–40. wound being pried off the trunk in order cultural commissioner’s office in your coun- to locate and kill the borer larva or pupa ty. See your phone book for addresses and Payne, P. B., and C. S. Koehler. 1980. underneath. phone numbers. Sequoia Pitch Moth on Monterey Pine. AUTHORS: S. H. Dreistadt, P. Svihra Oakland: Univ. Calif. Agric. Nat. Res. Notes: Pitch Canker. Oakland: Univ. TECHNICAL EDITOR: M. L. Flint Publ. 2544. Calif. Agric. Nat. Res. Publ. 74107. DESIGN, COORDINATION, AND PRODUCTION: M. Brush SUGGESTING READING Hickman, G. W., and P. Svihra. Planting ILLUSTRATIONS: Figs. 1, 3: C. M. Dew- Dreistadt, S. H., J. K. Clark, and M. L. Landscape Trees. 2001. Oakland: Univ. ees; Fig. 2: Adult moth adapted from Moul- Flint. 2004. Pests of Landscape Trees and Calif. Agric. Nat. Res. Publ. 8046. ton in E. O. Essig. 1913. Injurious and Beneficial Insects of California. Sacramen- Shrubs. 2nd ed. Oakland: Univ. Calif. to, CA: State Comm. of Hort.; Larvae and Agric. Nat. Res. Publ. 3359. Dreistadt, S. H., D. L. Dahlsten, and pupa by C. W. Woodworth. 1902. Univ. T. D. Paine. June 2000. Pest Notes: Bark Calf. Agric. Exp. Stat. Bull. 143. Wilker, K., T. R. Gordon, A. J. Storer, Beetles. Oakland: Univ. Calif. Agric. and D. L. Wood. February 2003. Pest Nat. Res. Publ. 7421. Produced by IPM Education and Publica- tions, UC Statewide IPM Program, Universi- ty of California, Davis, CA 95616-8620 WARNING ON THE USE OF CHEMICALS Pesticides are poisonous. Always read and carefully follow all precautions and safety recommendations This Pest Note is available on the World given on the container label. Store all chemicals in the original labeled containers in a locked cabinet or shed, Wide Web (http://www.ipm.ucdavis.edu) away from food or feeds, and out of the reach of children, unauthorized persons, pets, and livestock. Confine chemicals to the property being treated. Avoid drift onto neighboring properties, especially gardens containing fruits or vegetables ready to be picked. Do not place containers containing pesticide in the trash nor pour pesticides down sink or toilet. Either use the pesticide according to the label or take unwanted pesticides to a Household Hazardous Waste Collection site. Contact your county agricultural commissioner for additional information on safe container disposal and for the location of the Household Hazardous Waste Collection site nearest you. Dispose of This publication has been anonymously peer re- empty containers by following label directions. Never reuse or burn the containers or dispose of them in such viewed for technical accuracy by University of Cal- a manner that they may contaminate water supplies or natural waterways. ifornia scientists and other qualified professionals. 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