Electro-antennogram (EAG) detection analysis showing that weevil antennae strongly responded to blueberry flower extracts compared to clean air or solvent (methylene chloride). Bars, mean

1
Identification of host-plant attractants for the
cranberry weevil, Anthonomus musculus Say
(Coleoptera Curculionidae) Zsofia Szendrei1, Edi
Malo2, and Cesar Rodriguez-Saona1 1 Rutgers, The
State University of New Jersey, 125A Lake Oswego
Rd., Chatsworth NJ 08019, 2 Departamento de
Entomología, El Colegio de la Frontera Sur,
Tapachula, Chiapas, CP 30700, México
INTRODUCTION The cranberry weevil, Anthonomus
musculus Say (Coleoptera Curculionidae), is
native to North America and has been identified
as a pest on cranberries and highbush blueberries
since 1926 (Lacroix, 1926). In New Jersey,
weevils are a pest on highbush blueberries
(Vaccinium corymbosum L.) and cause significant
economic damage by feeding on and ovipositing
into the blossoms in April-May. The developing
larvae feed on the flower tissues and cause the
flower to drop prematurely. In New Jersey, this
pest has been controlled by broad-spectrum
insecticides, however the proposed regulatory
changes in insecticide use create a potential for
this insect to become a major pest. In fact, in
2007 New Jersey blueberry growers reported
outbreaks of this insect. Currently, the only
monitoring tool for cranberry weevils in highbush
blueberries is the use of beating trays, but this
method is labor intensive and might produce
misleading results because of patchily
distributed populations.
Behavioral assays with weevils and blueberry
plant parts
no choice
NUMBER OF FEMALE WEEVIL CHOICES
LEAF BUD
AIR
2
In Y-tube bioassays weevils were offered choices
of different blueberry plant parts. Female
weevils were not attracted to leaf or flower buds
compared to clean air, but they preferred open
flowers over flower buds (?27.7, Plt0.01). Male
weevils were attracted to intact flower buds
(?24.6, Plt0.05), but were repelled by damaged
flower buds (?27.9, Plt0.01). Further
investigation will be conducted using host-plant
chemicals to identify the volatiles responsible
for the observed behavioral responses.
FLOWER BUD
AIR
8
6
AIR
DAMAGED FLOWER BUD
AIR
4
FLOWER
DAMAGED FLOWER BUD
1
FLOWER BUD
LEAF BUD
FLOWER BUD
3

1
FLOWER BUD
FLOWER
Our goal in the current study was to investigate
host plant volatiles and pheromones in order to
develop an economical and effective monitoring
tool for this species. We identified host plant
volatiles and tested the response of weevil
antennae to some chemicals. In Y-tube assays we
examined the attractiveness of different plant
parts. Selected chemicals were tested in the
field for their effectiveness to attract weevils
to traps.
20
15
10
5
0
5
10
15
20
NUMBER OF MALE WEEVIL CHOICES
2
AIR
LEAF BUD
3

FLOWER BUD
AIR
5

DAMAGED FLOWER BUD
AIR
5
AIR
FLOWER
Highbush blueberry distribution in North America
3
FLOWER BUD
DAMAGED FLOWER BUD
FLOWER BUD
LEAF BUD
4
FLOWER
FLOWER BUD
4
Blueberry flowers
20
15
10
5
0
5
10
15
20
present
absent
Field test with cinnamyl alcohol and pheromone
lures
New Jersey
Cinnamyl alcohol is the main blueberry flower
volatile and we tested it in the field in two
different types of lures (see photos below).
Cranberry weevil attraction to the pepper weevil
lure was also tested. Yellow sticky traps were
placed at four commercial highbush blueberry
farms along the field edge near wooded borders.
Traps were monitored weekly for cranberry weevils
starting in early April.
Blueberry fruit
Source USDA-Plants Profile
An early-season pest the cranberry weevil feeds
on and oviposits into blueberry flower buds
causing economic loss.
New Jersey and Michigan account for 52 of the
total US blueberry production, valued at 255
million. The total value of the 2007 blueberry
crop in New Jersey was 90.2 million.
Response of cranberry weevil antennae to
blueberry volatiles
Average ( SE) number of cranberry weevils
Blueberry plant volatiles were identified and
cranberry weevil antennae were tested using
electro-antennograms for their sensitivity to
blueberry volatiles.
Electro-antennogram (EAG) detection analysis
showing that weevil antennae strongly responded
to blueberry flower extracts compared to clean
air or solvent (methylene chloride). Bars,
meanSE, with different letters are significantly
different, Plt0.05.


Pepper weevil (Anthonomus eugenii Cano) pheromone
lure baited traps caught significantly more
weevils than other treatments both in the first
and second generation (PROC GLIMMIX, P lt 0.05).

• CONCLUSIONS
• Cranberry weevil antennae respond to blueberry
  plant volatiles.
• Choice tests indicated that female weevils are
  attracted to blueberry flowers, while males are
  attracted to undamaged flower buds and are
  repelled by damaged flower buds.
• Yellow sticky traps baited with cinnamyl alcohol
  were not attractive to cranberry weevils, but
  pepper weevil lure baited traps attracted
  significantly more weevils than the control.
  Pepper weevil is a close relative of the
  cranberry weevil and it is likely that the two
  species share pheromone components.
• We will focus on investigating the role of host
  plant volatiles in developing monitoring traps,
  and test the pepper weevil pheromone components
  to understand the reason for its attractiveness
  to the weevils.
• ACKNOWLEDGEMENTS
• We thank the blueberry growers who let us use
  their farms in these experiments. Thanks to Vera
  Kyryczenko-Roth, Elizabeth Bender and Jud Parker
  for their help in the field study.

Cranberry weevil antennal response to different
blueberry volatiles. Hexyl acetate, cis-3-hexenyl
acetate, nonanal, methyl salicylate, cinnamyl
alcohol, and linalool oxide consistently elicited
a strong antennal response. Cinnamyl alcohol is
the major component of the blueberry flower
blend.