Notes on Stone Fruit Insects &
Mites
Obliquebanded leafroller
Identification
Adults are small, tan-coloured moths with three darker oblique bands
on the front wings. Larvae are green with black (instar 1-3) or brown
(instar 4-5) heads. Later instar feed inside tightly rolled leaves and
wriggle violently when -disturbed.
Obliquebanded leafroller (OBLR) larvae can cause significant damage by
feeding on the fruit during the shuck fall period. They tie nearby leaves
to the surface of fruit and feed on the fruit skin. OBLR larvae do not
tunnel into the fruit and prefer split-pit varieties.
Period of activity
OBLR overwinter as partially grown larvae in special cocoons under old
bud scales or bark of apple, pear, cherry and several other woody hosts.
Larvae emerge in the spring and feed on the bud clusters, flowers, expanding
leaves and developing fruit. OBLR does not successfully overwinter on
peach, nectarine or apricot because of cyanide content in the leaves.
Early season damage in these crops is usually the result of overwintering
larvae blown in from adjacent blocks of preferred hosts. Overwintering
larvae complete their development and emerge as moths from mid-June through
mid-July. The adult moths mate and their progeny, first generation larvae,
complete development from late July through late August. This generation
feeds on both foliage and fruit. There are two generations per year in
Ontario.
Monitoring and thresholds
OBLR has not been a significant problem on peach and nectarine since
a resistance management program for oriental fruit moth was introduced.
Pyrethroid use and timing for second to fourth generation OFM appears
to control OBLR. However, OBLR can be a serious problem in apricot. Monitor
for OBLR by checking shoots and fruit spurs from tight cluster through
to petal fall and from first cover to harvest. Control leafroller populations
in surrounding crops such as sweet cherry, apple and pear to reduce pest
pressure.
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