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PINE NEEDLE SCALE Chionaspis pinifoliae (Fitch) -- Homoptera, Diaspididae (Contacts) ----- CLICK on Photo to enlarge &
search for Subject Matter with Ctrl/F. GO TO ALL: Bio-Control Cases Pine needle scale
is a native North American insect with many coniferous hosts. An outbreak occurred in South Lake Tahoe,
California in 1968, which offered an opportunity to record a case of
naturally occurring biological control in a town environment (Dahlsten &
Hall 1999). South Lake Tahoe has
encroached into the natural westside forests of the Sierra Nevada Mountains,
where both lodgepole pine, Pinus
contorta Dougl. and Jeffrey
pine, Pinus jeffreyi Grev. & Balf.,
grow along the streets and in the town yards. Normally this scale occurs at low densities on both pine
species; however in 1968 populations soared in areas that had been fogged
with malathion for control of a mosquito, Culex
tarsalis Coquillett. The insecticide treatments were stopped
and the scale population declined within three years (Luck & Dahlsten
1975). A
uniparental population of scale was identified on lodgepole pine while a biparental
population occurred on Jeffrey pine (Luck & Dahlsten 1974). Different species of parasitoids were also
found on the different host tree species of the scale. The two scale parasitoids on lodgepole
pine were Physcus howardi Compere and Prospaltella bella Gahan. The parasitoid attacking scale on Jeffrey
pine was Acheysocharis phenacapsia Yoshimoto (Luck
& Dahlsten 1974). The coccinellid
predators Chilocorus orbus Casey var. monticolus Drea and Cryptoweisia atronitens (Casey) attacked the
scale on both pine species. Dominant
natural mortality factors were the coccinellids on both pine species and
parasitization by P. bella on lodgepole pine (Luck
& Dahlsten 1975). Other
homopterans, such as Nuculaspis
californica (Coleman), Pineus sp., Physokermes sp. and Matsucoccus sp., two mite
species, Oligonychus sp. and
Brevipalpus sp., and an
aphid, Schizolachnus sp.
were very abundant in the insecticide treated areas (Dahlsten et al. 1969,
Dahlsten & Hall 1999). REFERENCES: [Additional references may be found at: MELVYL Library ] Dahlsten, D.
L. & R. W. Hall. 1999.
Biological control of insects in outdoor urban environments. In:
Bellows, T. S. & T. W. Fisher (eds.), Handbook
of Biological Control: Principles and
Applications. Academic Press, San
Diego, New York. 1046 p. Dahlsten, D.
L., R. Garcia, J. E. Prine & R. Hunt.
1969. Insect problems in forest recreation
areas. Calif. agric. 23(7): 4-6. Luck, R. F. & D. L. Dahlsten. 1974.
Bionomics of the pine needle scale, Chionaspis pinifoliae
(Fitch), and its natural enemies at South Lake Tahoe, California. Ann. Ent. Soc. Amer. 66: 309-16. Luck, R. F.
& D. L. Dahlsten. 1975.
Natural decline of a pine needle scale (Chionaspis pinifoliae
(Fitch)) outbreak at South Lake Tahoe, California, following cessation of
adult mosquito control with malathion.
Ecology 56: 893-904. |