Biology Reference
In-Depth Information
186
187
186
Gall of
Adelges viridis
on terminal shoot of
Picea
.
187
Mature galls of
Adelges viridis
on
Picea
.
188
189
188
Adelges viridis
damage to foliage of
Larix
.
189
Colony of Scots pine adelges (
Pineus pini
) on
Pinus
.
190
Pineus strobi
(Hartig) (
190
)
syn.
P. strobus
(Ratzeburg)
Weymouth pine adelges
Essentially similar to
Pineus pini
but slightly smaller
and of North American origin, having been introduced
into Europe in the mid-1800s. It infests Weymouth pine
(
Pinus strobus
) and certain other five-needled pines,
and is widely distributed on such hosts in parks and
gardens. Overwintering nymphs mature and deposit
eggs about a month later than
Pineus pini
and, in
consequence, winged forms do not appear until mid-
June. A second, wingless generation develops during the
summer, and further egg clusters are produced during
August. Nymphs appear in August and September, and
eventually overwinter on the shoots. Considerable
amounts of white, waxen 'wool' are produced on
infested stems and younger branches.
190
Colony of Weymouth pine adelges (
Pineus strobi
).
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