Black Pineleaf Scale – Nuclaspis californica
Black Pineleaf Scale: Appearance, Territory, Damage, and Life Cycle
Latin Name: Nuculaspis Californica
Appearance: Mature scales are almost round, 0.06 inches in diameter, and range in color from yellowish-brown to black. Young are born in the spring and summer. Adult is 5/64 inches; oval, gray to black shells. crawlers (mobile stage) measuring 3/64 inches, colored yellow or orange, and lacking wings. While still in the sessile stage, nymphs are smaller than adults.
Scale feeding is limited to the needles, which get splotched with yellow spots. Scale insects are distinct from the normal insects we encounter. Many people mistake these scales for insects since they are tiny, stationary, and lack visible legs and antennae. Scale insects connect to the host plant, feed by inserting their mouthparts into the vascular system, and then cover themselves with a waxy shell or scale. The hard scale coating on the exterior protects the insect while it feeds on the host plant.
Hosts Plants: Scale of black pineleaf Nuculaspis californica may attack many pine species, as well as Douglas-fir and white fir on rare occurrences.
Territory: Black Pineleaf Scale is widely spread all over North America.
Damage Insect Cause: Heavy infestations induce early needle loss and may kill the tree. Affected trees frequently have a narrow crown, yellow or reddish coloring, and needle shortening. Maintaining the health and vitality of sensitive trees is the most effective way to reduce damage caused by this insect.
- Maintain healthy, stress-free trees.
- Scale populations on pines should be monitored.
- Scale crawlers were monitored using double-sided tape wrapped around twigs from early to mid-July.
- When monitoring shows the presence of crawlers, apply horticultural oil to smother scales or scale crawlers.
- In June, use a systemic dinotefuran soil drench, granules, or bark band.
Life History and Habits: The bug usually survives the winter on a half-grown scale. Depending on the temperature, eggs and juvenile nymphs (crawlers) will most likely arrive in June or July. If a second generation occurs, egg hatching and crawlers may reappear in late summer. Crawlers travel around on the needles or tree bark for several days before settling down to eat permanently on the needles. The crawler stage and very young scale insects are the most vulnerable to control efforts after egg hatching.