Biology and management of palm weevils

Biology and management of palm weevils

Biology and management of
palm weevils
Robin M. Giblin-Davis
University of Florida/IFAS
Fort Lauderdale Research and Education Center
Dryophthoridae:
Palm Weevils:(Rhynchophorini)
Rhynchophorus species
Dynamis borassi
Sugarcane/Palm Weevils:
(Sphenophorini)
Metamasius hemipterus and other
species
Rhabdoscelus obscurus
1
1
scutellum
Dynamis borassi
1. Rhynchophorus palmarum
R. cruentatus
Rhynchophorus
Distribution ca 1966
R. ferrugineus
R. ferrugineus expansion since 1966
R. bilineatus
R. palmarum
R. phoenicis
R. quadrangulus
R. bilineatus
1
R. palmarum
R. cruentatus
R. ferrugineus
2
R. phoenicis
R. quadrangulus
4
3
3
Rhynchophorus quadrangulus
Rhynchophorus cruentatus
Rhynchophorus ferrugineus
Male rostrum
without
setae 3
3a
Nasal
plate
Male rostrum
without
setae 3
Mandible
unidentate
Rhynchophorus quadrangulus
Mandible
unidentate
Rhynchophorus cruentatus
3b
No
nasal
plate
3b
3a
Submentum
narrow
Submentum
wide
Rhynchophorus quadrangulus
Rhynchophorus cruentatus
Rhynchophorus cruentatus
female
male
Rhynchophorus bilineatus
4
4
4
4
Rhynchophorus ferrugineus
4
4
1
Rhynchophorus palmarum
Rhynchophorus phoenicis
5
4a
Scutellum
tapers acutely
Scutellum
Tapers broadly
Rhynchophorus phoenicis
Rhynchophorus bilineatus
Rhynchophorus ferrugineus
5a
Submentum
straight
Rhynchophorus bilineatus
5b
Submentum
bowed
Rhynchophorus ferrugineus
R. cruentatus
Stressed Sabal palmetto
Intraspecific
Semiochemical:
Releaser pheromone: Chemical
released by sender with immediate
reversible effects on receiver (i.e. sex
and aggregation pheromones)
Primer pheromone: Chemical with
long term effects on physiology and
development of receiver (i.e. caste
determination and reproductive
synchrony)
Interspecific
Semiochemical:
Kairomone: Chemical released
that benefits the receiver, but not
the sender.
Allomone: Chemical that benefits
sender or sender and receiver.
10 live R. cruentatus
Weekly Weevil Counts from Traps Baited with 10
Live Rhynchophorus cruentatus and/or 1.5 kg of
Sabal palmetto Tissue
A
20
15
10
B
BC
CD
D
0
Females
Males
Palm Tissue
Males +
Tissue
Females +
Tissue
5
D
Empty
Dryophthoridae:
Palm Weevils:(Rhynchophorini)
Rhynchophorus species YES
Dynamis borassi
YES
Sugarcane/Palm Weevils:
(Sphenophorini)
Metamasius hemipterus and other
species
YES
Rhabdoscelus obscurus
YES
AERATION CHAMBERS
Porapak-Q
packed glass
columns
Gas Chromatograph with Electroantennographic
Detector (GC-EAD)
Sample
insertion
Flame ionization
detector (FID)
Carrier
gas
(Helium)
Split vent
GC Column
Electroantennographic
detector (EAD)
Oven
Electroantennogram
Amplifier
1:100
Ground
electrode
Chart recorder
Input
electrode
Ground
Antenna
Saline
solution
Fractions from the
gas chromatograph
Rhynchophorus cruentatus
FID
EAD
5-methyl-octan-4-ol
= Cruentol
Weekly Rhynchophorus cruentatus Counts from
Traps Baited with 5-methyl-octan-4-ol (0.4 mg/d)
and/or 1.5 kg of Sabal palmetto Tissue
50
A
40
30
B
BC
C
Palm Tissue
Tissue +
Cruentol
10
0
Empty
Cruentol
20
R. cruentatus
Rhynchophorus
Pheromone Distribution
R. ferrugineus
5-methyl-octan-4-ol
4-methyl-nonan-5-ol
(2E) 6-methyl-hepten-4-ol
4-methyl-nonan-5-ol
3-methyl-octan-4-ol
unknown
R. bilineatus
R. palmarum
R. phoenicis
R. quadrangulus
R. cruentatus
Metamasius
hemipterus
“Ferrugineol”
Distribution
R. ferrugineus
4-methyl-nonan-5-ol
5-methyl-octan-4-ol
4-methyl-nonan-5-ol
(2E) 6-methyl-hepten-4-ol
4-methyl-nonan-5-ol
4-methyl-nonan-5-ol
R. palmarum
R. bilineatus
Dynamis
borassi
Metamasius hemipterus
FID
Volatiles from unfed males
EAD
Metamasius hemipterus
FID
Sugarcane host volatiles
EAD
Metamasius hemipterus Counts from Traps Baited
with Ethyl Acetate (600-720 mg/d), 250 g of
Sugarcane, and/or Metalure
A
B
EA +
Tissue +
Metalure
EA +
Tissue
B
EA +
Metalure
B
C
Ethyl
Tissue + Acetate
Metalure (EA)
C
C
250
200
150
100
50
0
Metalure
Tissue
Metamasius hemipterus Counts from Traps Baited
with Metalure, 250 g of Sugarcane, and Different
Rates of Ethyl Acetate
A
A
100
80
60
B
B
40
20
0
1663 mg/d
403 mg/d
29 mg/d
0 mg/d
Ethyl Acetate Release Rate
Towards Making a Better Weevil Trap:
Semiochemicals: (Critical...need aggregation
pheromone(s) and host plant volatiles)
Design: (Simple is best...a bucket works)
Moisture: (Weevils seek high relative humidity to
conserve water because of high cuticular
permeability...Traps need moisture)
Size: (Larger buckets are better)
Color of trap: (Not critical)
Height: (Not critical for M. hemipterus... Not
critical for R. cruentatus if trap connected to tree
base)