a
[
ri;
ne
United Sktes
1 z;r Dep~tmentof
Agriatlwre
Forest Swim
Paeiflo Soeelhwmt
Foreat and Range
Exprlmenl Station
Avoid P anting Scotch Pine
Near Dwarf Mist
nfected
ifornia Pines
P.O. Box 245
Berkeley
California 94701
Research Note
PSW-400
R o b @F. Scharpf
a@m
,
f
iP.; M&&,
Arthur W. 1988. Avoid
pkldiPs8 Scotch p k Map
Rzisfle?f~-infectad Caf$ornia pines. Res. Note PSW-.
Berkelq, CA: Pacfic Solrrhwest Farest and
Range b~xpehentS~atim,Fo~rtSerwice, U.S.
wemt of A g r i d r e ; 2 p.
Eiat-year-old Scotch pine (Pinus sylvestris)
were merely id&
by dwad mb
ceakobim occ&ntafe) when plm& war inf d Diaerfim (P. sabbiana) in the foothiisof
the northern Siem Nevada, in California. But 6year-old knobcone x %
tev (P.attenua x P.
~ a d i a ~hybrid
a)
pines in the same planration were:
uninfeaed. To pwmt infection, avoid planting
Scotch pines near mtive CaliZmk pines baring
dwarf mirtletos.
Uelrievaf Term: dwrd m L b , h c e ~ l h o b i m
occklentab. Piow sylvcdtrb, P. dtanrcah x P. radialn, Chrirtma weer
Arthur H. McCaln
warf misllelae ( A P c e ~ b b i m
occi- pines were fire of dwarf mistletoe. The
Bentak Engelm.) infecls several na- Scotch pines were often heavily infected,
baring numerous infections per tree.
tive p i e s of pine in
Abundiant shoot development by many
Digger pine (Pinus
Monterey pine (P. radiata D. Don), Bishop mistlem plants also indicated a compatpine (P. muPicara D. Don), Coulter pine (P. able host-parasire relationsEp. Also, some
cou2tePr' D. Don), and knobcone pine (P. b r m development on branches indicated
infeclion may have m m e d shortly after
a t t e n ~lernm.).'
a
In addieion,
d u d pines, N e p p pine (P. hlepePasis p l a n a ~ o nes~lishment. The abmdance
also suggests that
Mill.), I ~ a snm e pine (P. pinea L.), and of infxtions in the
Japmese black pine (P. thunbergima intensification of the parasite is occurring
Franco) have a l s ~k o m e infecM when within individual Scotch pines as well as
p h r e d near dwarf mistlew-infected na- from dwarf mistletoe in adjacent overstory.
Because trees were planted only a few feet
tive pines?
This note reports the first known instance from one another, some lateral tree to tree
of Scotch pine (P. sylvestris L.) h o m i n g spread may also have occurred.
The absenceof infection in the knobconeidected by A. occidentale, and we recommend that Scorch pine not be plant& near Monterey hybrid trees is puzzling in that
d w d misaetm-infected California pine both parent species of this hybrid are native
hosts ofA. occidentale. The uees may have
slands.
The infect4 pines were located in a been too young to 'be infected or show signs
CRrlsmas tree plantation about 5 miles east of infection. However, we believe some
of JxPchon, California at about 2200 feet evidence of infection on some trees should
ebvalion in the fmthills of the northern have been present even though the hybrid
Siem Nevah. The plantation was estab- pines are 2 years younger than the Scotch
lished in 1982 with 2-0 Scotch pines and in pines. Additional examinations should be
1984 with 2-0 knobcone x Monterey hybrid made in the future to determine if the
pines (P. atrenuara x P. radiata). Both pine knobcone-Monterey hybrids remain free of
s p i e s ranged from about 4 to 6 feet in infection.
Scotch pine appears highly susceptible to
height in 1988. Large dwarf mistletoeinlFecledP. sabinianaadjacentto and within infection by A. occidentale, and is also inh planmtion were the initial source of fected by other North American dwarf
mistletoes as well. A. laricis (Piper) St.
infection.
mamination of numerous plantation John, A. americanum Nutt. ex Engelm., A.
m
s within range of nearby infected over- campylopodum Engelm., and A. vaginaturn
slopy showed that many Scotch pines were subsp. cryptopodum (Eingelm.) Hawks. &
i n f s w , but that the hokone-Monterey Wiens have all been reported to infect
USDA Forest Service Res. Note PSW-400. 1988.
-
Scotch pine when plant& near naturally
infected hosls.',3
Scotch pine appears to have little resistance to several North American s p i e s of
dwarf mistle~cle.Therefore, avoid growing
Scotch pine in areas when nearby native
hosts arenaturallyinfectedby dwarf mistletoes.
END NOTES AND REIPEWENCES
'Nawktwosth, Frank 6.;W k s . I ) E k & 1972.
Bidogy am' chsifiinlion of clwatf mktleber (Arh).
Ageic. h d b . 401. WarhiPlgton, DC:
U.S. w m e n t of Agriculture; 234 p.
fScharpf, 8. F.; kwlr$woreh, F. G. 19%. Erolic
piRU i g e c f d by two d w r / nnistlefoks irr ito~1Inam
Cal@w~~ia.
mant Diaeaw 70: 173.
%wksw&
F. G.; h u t , J. 6.1981. S ~ d l l p iP
k
suscepfible to so&hwes&rm d w i f m&fleloc.
Disease 665:163.
in
ROBERT FF. X m W F is poject l~~der-forest d i i s e reaebln91, with h d
Berkeley, W.ARTWUB W. M&AIN h aa exuensicrm p h t ptltologist. URivmily d
w o m i a , Berkeley.
USDA Forest S m i c e Res, Note BW-400.1988.