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±SE, with different letters are significantly different, P<0.05.

CONCLUSIONS1. Cranberry weevil antennae respond to blueberry plant volatiles.

2. 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.

3. 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.

4. 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.

ACKNOWLEDGEMENTSWe 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.

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.

Field test with cinnamyl alcohol and pheromone lures

Behavioral assays with weevils and blueberry plant parts

Response of cranberry weevil antennae to blueberry volatiles

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

INTRODUCTIONThe 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. 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.

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.

New Jersey

Highbush blueberry distribution in North America

present

absent

Source: USDA-Plants Profile

An early-season pest: the cranberry weevil feeds on and oviposits into blueberry flower buds causing economic loss.

EA

G R

es

po

ns

e (

mV

)

0

0.4

0.8

1.2

1.6

Air Methylenechloride

1 l 10 l

aa

b

ab

Blueberry plant volatiles were identified and cranberry weevil antennae were tested using electro-antennograms for their sensitivity to blueberry volatiles.

Linalool

Air

Hexyl acetate

Methyl salicylate

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.

LEAF BUD AIR

FLOWER BUD AIR

AIR

AIR

DAMAGED FLOWER BUD

FLOWER

FLOWER BUD DAMAGED FLOWER BUD

FLOWER BUD

FLOWER BUD

LEAF BUD

FLOWER

NUMBER OF FEMALE WEEVIL CHOICES

20 15 10 5 0 5 10 15 20

LEAF BUD

FLOWER BUD

DAMAGED FLOWER BUD

FLOWER

FLOWER BUD

FLOWER BUD

FLOWER BUD

AIR

AIR

AIR

AIR

DAMAGED FLOWER BUD

LEAF BUD

FLOWER

NUMBER OF MALE WEEVIL CHOICES

20 15 10 5 0 5 10 15 20

no choice

2

8

6

4

1

3

5

3

1

5

2

3

4

4

*

*

*

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 (χ2=7.7, P<0.01). Male weevils were attracted to intact flower buds (χ2=4.6, P<0.05), but were repelled by damaged flower buds (χ2=7.9, P<0.01). Further investigation will be conducted using host-plant chemicals to identify the volatiles responsible for the observed behavioral responses.

Cinnamyl alcohol“Bubble”

0mg 100mg 0mg 100mg30mgCinnamyl alcohol

“SPLAT”

Pepper weevil pheromone lure

0

0.5

1

1.5

2

Control-no lure

First generation

Second generation

a ababb

ababb

A

BB B B

B

B

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 < 0.05).

Ave

rag

e (±

SE

) n

umbe

r o

f cra

nb

erry

we

evi

ls

Blueberry flowers

Blueberry fruit

0

0.2

0.4

0.6

0.8

1

1.2

1.4

Air

Hexyl a

cetate

Hexyl b

utyrate

Hexyl-2-m

ethyl butyrate

Cis-3-h

exenyl aceta

te

Cis-3-h

exenyl pro

pionate

Cis-3-h

exenyl bu

tyrate

Cis-3-h

exenyl he

xano

ate

Cis-3-h

exenyl-2-m

ethyl bu

tyrate

2-Un

deca

none

Non

anal

Tride

cane

Meth

yl salicyla

te

Hexan

ol

Cinna

myl a

lcohol

Eu

calypto

l

Linalo

ol oxide

Linalo

ol

-P

inene

-Pinen

e

Caryop

hyllene o

xide

Caryop

hyllene

-H

umulen

e

(R)-(+

)-Lim

onene

Myrcen

e

Ocim

ene

-Fa

rnese

ne

Fa

rnese

ne

EA

G R

esp

on

se (

mV

)