MATING DISRUPTION OF PLANOCOCCUS FICUS IS NOT AS

MATING DISRUPTION OF PLANOCOCCUS FICUS
IS NOT AS SIMPLE AS FOR LOBESIA BOTRANA
BUT
MIGHT HAVE ADDITIONAL ADVANTAGES FOR
NATURAL ENEMY'S EFFICIENCY.
Rakefet Sharon1,4, Tirtza Zahavi2, Tamar Sokolsky1, Niv Nir1, Ally Harari3
1Northern
Research and Development. MIGAL Institute. 2Extension Service, Ministry of
Agriculture. 3Department of Entomology, ARO. 4Department of Science, Ohalo College, Israel.
Mating disruption, based on the species specific sex
pheromones, is considered an efficient environmental
friendly method.
o The vine mealybug Planococcus ficus (VMB) is a
major pest in vineyards. VMB is the vector of
leafroll disease- demand for low population.
o Control methods of P. ficus population are based on
organophosphates and neonicotinoids.
o However, the effectiveness of some is deteriorating
and the demand for environmentally friendly
control approach is growing.
Mating disruption, based on the species specific sex
pheromones, is considered an efficient environmental
friendly method.
Population
size
• Consecutive
years effect
Mating
disruption
Females
fitness
Natural
enemies
• Mortality
• Offspring
• Attractant
• Searching
ability
Mating disruption principal
Mechanism hypothesis:
1. Reduced response via saturation of the males receptors
(sensory adaptation).
MD
All the receptors are occupied by pheromone
molecules- no response by the male
4
Mating disruption principal
Mechanism hypothesis:
1. Reduced response via saturation of the males receptors
(sensory adaptation).
2. Concentration gradient is masked by pheromone saturated
area.
MD
The male cannot locate the pheromone source
5
Mating disruption principal
Mechanism hypothesis:
1. Reduced response via saturation of the males receptors
(sensory adaptation).
2. Concentration gradient is masked by pheromone saturated
area.
3. Reduced mating via competition between the
females and the synthetic pheromones.
MD
The male “wastes” time and energy
6
Mating disruption principal
The environment is saturated
with the sex pheromone
Males have difficulty in locating
the females
Less mating
Pest population reduced
MD
Less damage
7
Mating disruption, based on the species specific sex
pheromones, is considered an efficient environmental
friendly method.
o Does it work on VMB population like it works for moths?
MD creates a pheromone saturated environment that might
have other implications:
o One unstudied aspect of MD might be through the
effects of excess sex pheromone as conceived by
the VMB females.
It was shown with moth species to reduce female
fitness, suggesting there is a biological cost of
pheromone production in females (Harari et al. 2011).
o Another aspect is the MD effect on the VMB natural
enemies.
P. Ficus life cycle
o Does it work on VMB population like it work for moths?
Like moths
The male flies towards the
female's pheromone source.
Unlike the moths
The VMB female is wingless
Overlapping generations
The winged adult male, does
not feed and lives 2-3 days.
4-6 cycles/year
3-6 weeks
Population
size
P. Ficus Mating disruption method
Same as moths
Monitoring
traps
Mating
disruption
dispenser
MD efficiency
Population
size
10
P. Ficus Mating disruption method
Unlike moths- Once the male find a female it might
encounter VMB colony and can mate with many females
Monitoring
traps
Mating
disruption
dispenser
MD efficiency
Population
size
11
P. Ficus Mating disruption results
A
VMB on vines
10
Three vineyards 0.5 hectare (vineyard as replicate) 2009-2012
2011
AB
8
6
VMB on vines
12
B
4
2
0
MD 1st
year
AB
4
2
B
MD 2nd
year
A
2012
B
15
C
10
control
5
C
2.5
Ovisacs on vines
25
VMB on vines
2010
A
0
control
20
6
0
2
MD 1st MD 2nd
year
year
A
A
1.5
1
B
0.5
B
Population
size
0
Control
MD I
MD II
MD III
Control MD I
MD II MD III
P. Ficus Mating disruption results
VMB on vines
12
st year
A
MD
effect
in male
traps
is
demonstrated
from
the
1
2011
10 VMB population reduction is effective from 2nd year
AB
8
6
B
4
2
3
2.5
2
control
MD 1st
year
control
MD 2nd
year
MD 1st year
MD 2nd year
1.5
1
0.5
Odem
Mehadrin
Apr
May
Jun
Jul
Aug
Sep
‫מרץ‬
Apr
May
Jun
Jul
Aug
Sep
0
Apr
May
Jun
Jul
Aug
Sep
Oct
Males/trap/day
0
Meron
Population
size 13
Mating disruption, based on the species specific sex
pheromones, is considered an efficient environmental
friendly method.
Mating
disruption
Population
size
Females
fitness
•Consecutive
years effect
MD dispensers effect on VMB females fitness and instars
MD creates a pheromone saturated environment- The
effects of excess sex pheromone as conceived by the
VMB females.
We tested the VMB pheromone effect on VMB fitness:
o Adult females were collected from the field and placed on
potatoes in plastic boxes (30 x 20 x 20 cm) covered with
netted lid.
o To 10 boxes we added a pheromone dispenser, and 10
were left as a control.
o We monitored the boxes every 2-4 days and recorded
VMB by development stage.
Females
fitness
MD dispensers effect on VMB females fitness and instars
Mortality of females was detected only in the pheromone
boxes.
Instars were found in 80% control boxes and in 50% of the
pheromone treatment boxes.
100
Control
200µg
percentage
80
60
40
20
0
Crawlers
Females survival
Females
fitness
Instars number
(Mean±SE)
MD dispensers effect on VMB females fitness and instars
o The average number per box was higher in the control (7
boxes) than in the treatment (5 boxes).
o More VMB instars were found in the control (61/5) than
in the pheromone (37/5) boxes.
o A delay in the instars appearance was seen in the
pheromone boxes and, in the beginning, instars appeared
only in the control boxes.
14
12
10
8
6
4
2
0
200µg
N=5 ;
6
8
10
Control
N=7
13
Days
15
17
20
Females
fitness
Mating disruption, based on the species specific sex
pheromones, is considered an efficient environmental
friendly method.
Population
size
• Consecutive
years effect
Mating
disruption
Females
fitness
Natural
enemies
• Mortality
• Offspring
MD effect on VMB natural enemies
The MD is the effect on the VMB natural enemies.
Host searching capacity is crucial aspect of a successful
natural enemy’s biology and its affectivity is used in biocontrol (Heidari and Copland, 1992).
The lady beetle Cryptolaemus montrouzieri and the
parasitoid Anagyrus pseudococci are important natural
enemies of mealybugs, including VMB (Mustu et al., 2008;
Daane et al., 2012) and both, parasitoids and predators,
help in decreasing P. ficus population.
Natural
enemies
MD effect on VMB natural enemies
The natural enemies, parasitoids and predators, help in decreasing P.
ficus population.
Augmentation by the parasitoid Anagyrus pseudococci and the
predator Cryptolaemus montrouzieri is now, in Israel, a supplement
method.
Specimens number (mean)
14
12
10
2005
Anagyrus
adult&larvae
males/day
8
6
4
2
0
Apr May Jun Jul Aug Sep Oct nov
Natural
enemies
MD effect on VMB natural enemies
A. pseudococci have been shown to be attracted by their host (VMB)
sex pheromones (Franco et al., 2008).
In coccinellid, host searching can use visual (Maredia et al., 1992) or
chemical cues or combination of the two (Bahlai et al., 2008).
Adults and larvae feed from VMB .
The effect of the pheromone as cue for C. montrouzieri was not
yet shown
Natural
enemies
MD effect on VMB natural enemies
o Response of C. montrouzieri to olfactory stimuli as tested
by olfactometer.
The numbers of individual C. montrouzieri that chose the
offered components: vine leaf (Leaf) vs. air, vine leaf vs.
VMB pheromone (Pheromone) and pheromone vs. it solvent
(Solvent).
Solvent
Pheromone
p=0.005
Leaf
Pheromone
p=0.04
Blanc
Leaf
p=0.27
-20
-10
0
Number of specimens
10
20
Natural
enemies
Searching ability of C. montrouzieri. Observation from 9 plots (0.1 hectare)
0.35
0.3
C.montrouzieri
0.25
0.2
0.15
0.1
0.05
0
Control
-0.05
CM
0
May
MD
Control
CM
7
Jun
MD
Control
CM
MD
14
Aug
weeks from augmentation by treatments
C. montrouzieri- CM highest level in Jun (p=0.0003)
MD highest level in Jun (p=0.006)
Control highest level in August (p=0.003)
Natural
enemies
CONCLUSIONS• Mating
Populatio disruption
n size • Consecutive
years effect
Females
fitness
Natural
enemies
• Mortality
• Offspring
• Attractant
• Searching
ability
CONCLUSIONSPopulation
size
Females
fitness
Natural
enemies
Mating disruption method against p. ficus is an
effective control method when applied for at list
two consecutive years even when the initial
population level is high.
VMB females fitness is affected by the pheromone
saturated environment- There might be additive
effect of MD method through the pheromone
influence on the VMB fitness.
The lady beetle C. montrouzieri is attracted to
VMB pheromone- the saturated environment
might enhance the searching capacity and ability
of the natural enemies to locate VMB.
Tirtza Zahavi
Tamar Sokolsky
Carmit Sofer-Arad
Maor Tomer
Niv Nir
Ally Harari
Acknowledgments- The Israeli Ministry of Agriculture,Chief Scientist, the
Israeli wine board and Makhteshim Agan company.
P. Ficus life cycle
1week
2weeks
7-14
Crawler
Ovisac
3weeks
25ºC
2nd
instar
3rd
instar
4weeks
3-7
Ovipositor
Female
Male prepupa
Adult
Female
2-4
Adult Male
4-6 cycles/year
Male pupa
5-7
MD effect on VMB natural enemies
Natural
enemies
Shaul BioBe
P. Ficus Mating disruption method
Monitoring
traps
1.26
Mating
disruption
dispenser
1.24
gram
1.22
1.2
1.18
1.16
MD efficiency
1.14
1.12
start
Apr
one
May
two
Jun
three
Jul
Populati
on size
month
Dispensers active duration
29
MD effect on VMB natural enemies
Cryptolaemus montrouzieri larvae
may
jun
aug
MD
Augmentation
Control
MD
Augmentation
Control
MD
Augmentation
Vines with VMB
Control
Specimens on monitored
vines (%)
Searching ability of C. montrouzieri
Observation from 9 plots (0.1 hectare)
70
60
50
40
30
20
10
0
Natural
enemies
7
VMB
C.montrouzieri
0.3
0.25
VMB/vine
5
0.2
4
0.15
3
0.1
2
0.05
C. montrouzieri/vine
6
0.35
1
0
0
-0.05
Control
CM
May
0
MD
Control
CM
Jun
7
MD
Control
CM
MD
Aug
14
weeks from augmentation by treatments
C. montrouzieri- CM highest level in Jun (p=0.0003)
MD highest level in Jun (p=0.006)
Control highest level in August (p=0.003)
Natural
enemies
MD effect on VMB natural enemies
Specimens number (mean)
14
Anagyrus
2005
adult&larvae
12
males/day
10
The natural enemies, parasitoids
and predators, help in decreasing
P. ficus population.
Augmentation by the parasitoid
Anagyrus pseudococci and the
predator Cryptolaemus
montrouzieri is now, in Israel, a
supplement method.
8
6
4
2
0
Apr May Jun Jul Aug Sep Oct nov
16
Specimens number (mean)
2006
14
12
Anagyrus
adult&larvae
males/day
10
8
6
4
Natural
enemies
2
0
April may jun
jul
aug sep oct