Insects on shrubs
ARBORVITAE LEAFMINERS
(Tip Moth)
There are four species of arborvitae leafminers in the Northeast, although the arborvitae leafminer, Argyresthia thuiella, is the most common in New York State. The major food plant is arborvitae (Thuja). The adults are tiny
(3/8 inch wingspan) white to light gray
moths with brown markings on the forewings. The larvae or caterpillars are 1/8 inch in length with a light green (sometimes with a reddish or yellow tinge)
Mined leaves have at first a translucent or straw color, later turning brown Mines start near the end of a branchlet in the scale-like leaves and extend into other branchlets. Injury begins in the summer and reaches a climax in the fall Death of mined branchlets often occurs giving the tree a sickly appearance. The greatest injury probably occurs to hedge rows and ornamental plantings.
The adults are active from late May to early June. Many tiny glittering moths may callattention to an infestation. After mating, the females deposit eggs on the inner edges ofthe arborvitae leaves. The young larvae enter the leaves and mine or excavate between the leaf surfaces .The larvae over winter in the mines and resume feeding for a short while the following spring. Pupation occurs in late May and the adults emerge soon after.
Control
March-June: Use systemic granules or systemic liquid to kill active larvae.
Use Bio Pak Plus monthly to stimulate necessary leaf growth.
May-August: Use Liquid Sevin to kill active moths.
Use Bio Pak Plus monthly to stimulate necessary leaf growth.
August-October: Use systemic granules or systemic liquid to kill active larvae.
Use Bio Pak Plus monthly to stimulate necessary leaf growth.
Preventative Maintenance
March-October: Use systemic granules or systemic liquid every 6 weeks to prevent adult infestation. Use Bio Pak Plus every 2 months to stimulate necessary leaf growth.
Fertilizing
