Juniper twig girdler—Periploca nigra
The juniper twig girdler adult is a small, shiny, brownish black moth. The adult is not often seen. Mature
larvae are cream colored with brown heads.
Identification of species
Damage
The smaller limbs of infested junipers become yellow, then turn brown and die. This branch
"flagging" is most apparent in the late summer and causes a checkerboard of green and brown
limbs and retarded plant growth. Under the twig bark, larvae and the characteristic girdling tunnels can
be seen. Twig girdler feeding does not kill entire juniper plants.
Solutions
To improve plant appearance, prune out and
dispose of affected branches. Tam juniper,
Juniperus sabina 'Tamariscifolia', is extremely susceptible
to damage; avoid planting this variety and consider replacing
existing plantings with more resistant junipers. Hollywood
junipers, J.
chinensis
'Kaizuka' or 'Torulosa', are resistant to juniper twig girdler
attack. If damage cannot be tolerated, thoroughly spray foliage
with a persistent insecticide such as permethrin twice
annually. Spray about late March and early May in Southern
California
and early June and middle July in Northern California. Insecticide
kills adult moths and prevents them from laying eggs, but
boring larvae are not
affected and spraying does not restore the appearance of
damaged foliage, which remains brown until new growth occurs.
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Dead
patches caused by Juniper twig girdlers
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