What's Hot at the PPDL
October 13, 2015
Hackberry Psyllids 2015
Timothy Gibb, Department of Entomology, Purdue University
Hackberry psyllids are back. We are getting lots of
reports of these tiny black colored, jumping bugs all over houses and
especially at window screens. They are tiny enough to pass through
Psyllids are a group of small insects called jumping plant
lice, and the name fits. They are tiny, plentiful at times and they do
jump when disturbed.
In the late fall adult Hackberry psyllids emerge from
their galls and fly, sometimes congregating on windows and screens.
They are often described as tiny black jumping insects and are quite
small - small enough to actually pass through the mesh of many window
screens. That is why homeowners report them as being a nuisance in the
home. They also fly to windows again in the late winter or early
spring when temperatures begin to warm.
Under a microscope Hackberry psyllids resemble a miniature cicadas – large eyes and with wings held roof-like over the back.
They pass the winter as adults and lay eggs again during
the spring time on the emerging leaves of hackberry trees. When the
eggs hatch, the tiny nymphs act like other gall-making insects by
causing the leaves to form the distinctively shaped gall that they are
named after. The tiny nymphs live and grow inside this protective gall.
As summer progresses, the leaves can sometimes be covered with them.
These are not a serious pest of hackberry trees because
the galls, although very conspicuous, do very little damage to the
leaf. Hackberry psyllids are mostly considered to be a nuisance pest
when they get into homes.
Chemical treatments are seldom warranted. To prevent them
from entering the home simply close the windows during the short period
of time when they are active.