Pear Sawfly, Hoplocampa brevis (Foerster)
I. Introduction: Closely related to the
European apple
sawfly (Tenthredinidae). This pear sawfly is a separate species
from
another sawfly species on pear, commonly known as pear slug,
which is a
foliar feeder. On May 24, 2005,
Mark Brown, Appalachian Fruit Research Station, USDA-ARS, at
Kearneysville, announced that for the
last 3 years Richard Bell, pear
breeder, and Rob Alleman, technician at AFRS, have
noticed "apple sawfly-like" damage to pears. Dave Smith (USDA,
ARS, Systematic Entomology Lab) has determined from specimens collected
from pears at
AFRS that these are pear sawfly, Hoplocampa brevis.
It
has
probably been in the area for several years (it was
found in Pennsylvania and Maryland in
the mid-1960's). Pear fruit do not show the spiral type of
injury that
apples show from early apple sawfly instar damage, but the fruit is
scarred and most of the damaged fruit drop before "June drop".
II. Hosts: Pear sawfly develops on
pear. Another common name is cherry sawfly.
III. Description: Adults are
reddish-yellow, with yellow legs. Length is 4-5 mm (smaller that
EAS). Larvae are
8-12 mm. Color of larvae is yellow-grey with a reddish-brown head.
The INRA web
site (in French) contains several photos:
http://www.inra.fr/Internet/Produits/HYPPZ/RAVAGEUR/6hopbre.htm
Adult
on bloom, egg
and oviposition scar, injury
on young pears, injury
with moist frass.
IV. Biology: Adut females lay eggs on pear
blossoms at late bloom. The larvae burrows beneath the surface of
the fruit before digging in to the center, where it feeds on the
seeds. This is termed primary attack. A larvae may leave the
fruit and attack a second fruit (secondary attack). Larvae drop
to the ground, where they overwinter. Pupation occurs in the spring.
V. Injury:
Larvae feed internally in fruit, producing tunneling and moist frass.
Injured fruit are more likely to drop prematurely.
Additional
references:
- INRA
(National Institute for Agricultural Research) web site
(http://www.inra.fr/Internet/Produits/HYPPZ/RAVAGEUR/6hopbre.htm).
- Ontario
Ministry of Agric. and Food. 2005. Pear sawflies: Were tey a
problem in your orchard last year? web
site.
(http://www.gov.on.ca/OMAFRA/english/crops/hort/news/hortmatt/2003/04hrt03a5.htm).
Downloaded
25
May 2005).
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