Notes on Apple Insects
European apple sawfly
Identification
European apple sawfly (EAS), an introduced pest of apple, was first identified
in eastern Ontario in 1987. Since then, it has been steadily moving westward
through apple production areas and in 2005, populations were found in
the Colborne area.
Adults are 6-8 mm long with dark brown heads and antennae. The lower
body is light orange to -yellow. Mature larvae are cream-coloured, 9-11
mm in length and easily confused with caterpillars.
EAS causes two types of injury to apple. First instar larvae feed under
the skin of the fruit and create a heavily russeted, winding ribbon-like
scar in the shape of a spiral from the calyx end of the apple. Secondly,
as the insect matures, it creates a hole in the fruit and moves towards
the seed cavity. This damage often causes the fruit to drop.
Period of activity
EAS adult flight begins during the pink stage of apples and continues
through bloom until petal fall. There is one generation per year.
Monitoring and thresholds
EAS are monitored through the use of visually attractive, three-dimensional
traps that consist of non-UV reflecting white sticky boards, which mimic
the colour of blossoms. The action threshold for EAS is six sawflies per
trap if a prebloom insecticide was applied or three sawflies per trap
if no prebloom insecticide was applied.
Management notes
Currently petal fall sprays of azinphosmethyl (Guthion Solupak, Sniper)
are the only options available for the management of this pest.
Learn more...
