You may get to enjoy the first crop of roses if soil
temperatures remain cool early on, but once the adults emerge and
begin laying eggs, you would be lucky to see even one normal flower.
Many generations develop through the growing season.
lay their eggs in flower buds or expanding leaf buds or even the
tender tissue of elongating shoots. Those eggs hatch quickly, and
the young larvae immediately begin to cut into tender buds and stem
tissue to obtain the sap. The injured tissue dies, turning brown at
first, then black. It is common to find as many as 10 to 15 larvae
on a single bud. They are very tiny, less than 2 millimeters long.
You can see the creamy white to pale red larvae on close inspection.
Life Cycle of the Rose Midge
It only takes about two weeks
for them to complete their life cycle during warm summer weather.
Adults are inconspicuous reddish-brown flies. They do not feed at
all and only live for a day or two.
targeted at the first generation can drastically reduce or even
eliminate the need for treatment later in the season. Bayer Advanced
Power Force Multi-Insect Killer (cyfluthrin), Bayer Advanced Garden
Rose & Flower Insect Killer (cyfluthrin and imidacloprid), and
pyrethrins and piperonyl butoxide are labeled to control rose midge
applications as roses begin to leaf out in the spring. Make two more
applications at 10-day intervals to ensure good control. Although
many organic gardeners prefer to use pyrethrins without piperonyl
butoxide, pyrethrins alone may not provide significant control. Some
sources suggest that BioNeem (azadirachtin) may provide some control
of this pest, but Penn State University's Woody Ornamental Insect,
Mite and Disease Management guide does not list it.
Azaleas and Rhododendrons
Lilacs that aren't Blooming