White peach scale has significant financial impact for commercial peach growing operations. White peach scale insects cause peach tree leaves to yellow and drop, decrease fruit production, and can lead to premature death of the tree.
For home gardeners and commercial growers alike, catching and combating the problem in the early stages of infestation is advantageous.
What is White Peach Scale
White peach scale insects (Pseudaulacaspis pentagona)
are tiny armored bugs which consume sap and infest the bark, leaves, and fruit
of trees such as peach,
cherry
and persimmon.
These insects can inhabit over 100 species of plants and have worldwide
distribution.
These insects are very small, with adult females averaging
3/64 to 3/32 of an inch (1 to 2.25 mm.). Mature females are white, cream, or
grayish in color and can be identified by the yellow or red spot that gives
these bugs the appearance of a fried egg. Adult females remain immobile, but
young females spread to new areas before laying eggs. Fertilized females
overwinter on the trees.
The adult male of the species is smaller than the female,
orange in color, and only lives about 24 hours. Wings give the males the
ability to fly and locate females via pheromones. Both male and female nymphs
are smaller than the adult female. Depending upon the climate, more than one
generation can be produced in a year.
Control of White Peach Scale
Control of white peach scale is made difficult due to the
heavy armor which protects these bugs. The best time to apply oil is early
spring when the first generation hatches and begins migrating. Monitoring this
crawler stage can be accomplished by wrapping infested limbs with double-sided
or electrical tape (sticky side out). Check the tape at least twice a week,
using a magnifying glass to detect live bugs. Oil
sprays are most effective against the immature insect pests.
Biological control can also be effective for white peach
scale treatment in backyard trees and small home orchards. Predator
bugs which prey on white peach scale insects include ladybird
beetles, lacewings
and parasitic
wasps. Some species of predaceous thrips
and mites
as well as gall
midges attack white peach scale.
Gardeners and commercial growers wishing to use chemicals
for white peach scale treatment are advised to contact their local
extension office for recommendations. Properly timed treatments are more
effective and new products may be available.
Finally, proper orchard management reduces stress and
promotes healthier fruit trees This, in turn, helps trees overcome white peach
scale damage.
