With the weather warming up you might be noticing some insect activity.
The most prevalent I've seen is pine needle scale. Here's what to look for: White and black specks with in your branches. This scale targets conifers and I have seen most in afghan pines, scots and red pines.
To treat for pine needle scale, "Chionaspis pinifoliae," when you see visible insect activity sometime around March and April. It is during this time that the eggs have hatched into young crawlers that are moving about on plants, and these young crawlers are most susceptible to insecticide applications.
Mature pine needle scales are 2 to 3 millimeters long, elongated, white scales on the needles of evergreens. Pine needle scale overwinters as eggs underneath the mated female scale cover.
Females are capable of laying up to 100 eggs during their lifespan. Eggs hatch into crawlers from late April through June. Crawlers move around on the needles before finding a place to settle and feed. They withdraw plant fluids from the mesophyll layer of needles, causing the needles to turn yellow, then brown. Whole branches may be killed.
Also, heavy infestations of pine needle scale can kill entire trees, particularly those pine trees that are stressed. Young crawlers may be blown onto other plants by wind--starting another infestation. There are typically two generations per year in New Mexico.
As with many insect and mite pests of ornamental trees and shrubs, management of pine needle scale revolves around sustaining plant health and using insecticides accordingly. Properly implementing cultural practices--including irrigation, fertility, and mulching — minimizes stress and allows plants to tolerate low to moderate populations of pine needle scale without suffering injury. Insecticides recommended for controlling pine needle scale include acephate (Orthene), insecticidal soap, and horticultural (summer) oil.
About Pine Needle Scale
Pine Needle Scale lives on pine and spruce.
Mature scales are tiny insects that are covered by a white, oblong, waxy protective covering that is 2.5 to 3 mm in length.
Scales overwinter as eggs beneath female scales on the needles. In May, crawlers hatch and migrate to new needles on the tree. The crawlers then molt to an immobile nymph stage that feeds on the sap and secretes the scale covering. In the fall the scales mature and lay eggs for a second generation.
By August needles become spotted with white elongated scales. Damaged needles are discolored and may fall prematurely. Severely infested trees are less vigorous and occasionally may be killed.
Thoroughly spray foliage, branches, and trunk with a dormant oil in March or with malathion, diazinon, acephate, or chlorpyrifos in early June.
Control is not effective after the insects have formed their protective waxy scales. Some kind of systemic also works well and can be applied at any time, preferably in the Spring.