kp, (,lt ‘) *I _..+a 1 I ...
kp,
(,lt ‘)
*I
_..+a
1
I
--~00*03
%
Study of changes in Heliothis armigera flights with synthetic
pheromone traps in Senegal
L. BOUREXICXHE
Summary
The aldehyde (Z)-ll-hexadecenal was tested with good results as an attractant for the mdle
Heliothis armi~era, the major tomato pest in Senegal. Traps baited with this synthetic iex
pheromone afforded an opportunity io study the activities of the adult moth in tha Cape
Verde region of Sçnegal, a major vegetable-producing area. According to the 1979 finding\\,
this peut was most active durin g the February-April dry season with sharp praks in
mid-February and at the end of March.
During the rainy season (mid-August throu;h
December), it disappeared. Using the pheromone trap technique, control cari now Se
oriented toward planned measures adapted to local conditions as oppowd to sqstema!ic
applications of pesticides.
The tamato math Heliotitis urtnigera (Hiibn.)
The pheromone traps wrre utilizzd through-
(Lqi&~ptera, Noctuidae) is polyphagous and
out the year, beginning in Nobernbrr 1978.
causes substantial losses to various crops in
These are made of two plastic rectang!es joined
Africa.
In Senegal, it is the major tomato
at each corner by rings. The inside of the
pest. causing losses ranging from 10 to 90 per-
bottom rectangle is covered with a sticky sub-
cent accnrding to region or season (Collingwood
stance.
A small rubber capsule saturatrd vcith
and Bourdouxhe, 1980). More detailed knowl-
the synthetic sex pheromone Z-1 1 -C,,:AId.’
edge of thr seasonal activities of these Lepidop-
is attached at the centre of the sticky surface.
tera was necessary in order io organize control
The baited traps were hung from poles 1.25 m
measures and the applications of pesticides
off the ground (higher than the tops of the
whzre and when really needed.
tomato plants) at intervals of at least 50 m.
In 1977 Piccardi et al, (1977) isolated from
They were inspected every day for captured
the abdominal tip of H. armigera virgin fe-
males. The capsule was replaced everq wçek
males a compound that they identifïed as (2,-I l-
and a new coating of the sticky substance was
hsxadecenal. Both laboratory (Gothilf et al.,
applird to the bottom rectangle every ten to
1978; Piccardi et ai., 1977) and field trials in the
15 daqs, as its stickiness waned.
Sudan (Piccardi et ~1.. 1977) have shown this
aldehqde to be a potsnt olfactory stimulant
Resultr and discussion, ne pheromonc proved
for thc male H. m-migmi.
to be highly specific. Despite the presence of
Thz tes: technique ch<>,jen for studying the
numerous other species of maths. only the
changing pattzrn of H. tzrmigmz flights in the
H. urmigercz male was caught.
Cape Verde region of Senrgal was the synthetic
To offset variations in the daily catch sauïed
se3 phc’r~mi)ne trap.
by outside influences, it was decided to use
wetkly total catch figures.
Based o n theqe
klatrrialj and methods. Thc triais wers con-
totals. a histogram (Figure 1) was prq~rsd
ductcd in 1979 at the Centre pour le dévelop-
diagramming the year-long activities of the
pemcnt de l’horticulture about 10 km east of
adult insect and showing thz changing pattrrn
Dakar in the Cape Verde rcgion.
of H. mnziger~z flights in the arca selezted for
the esperiment. The first importsnt catches
in 1979 occurred during the second week of
- - - - -
l Supplied b y Montedi>on.
107
January. There uere two subsequent pcaks
ably to reproduce successive gencratitins. The
of maximum activity: the second week of
main features of the histogram appear to be
Frbruary, -v+ith a peak figure of 65 males
rcpeated for the late i979,‘early 1980 period.
tr,tpped, and the las1 week of March. with 48
.4s in the catch histogram, Figure 2 shows
catches. The time interval between the two
changes in the percentage of tomatoes attacked
peaks of activity corresponds roughly tu the life
by H. amigera.
The tomatoes were picked
c)cie of one generation.
Catches continued
once a week, throughout the year, from un-
to he frequent in April, dropped in May and
treated plots. The percentage of fruit destroyed
became increasingly rare in June and July.
rises rapidly with the onset of flights and well
No catches were recorded between August
before peak catches of adults. This is probably
and mid-December. This is due to the migra-
due to the unusual fecundity of the females,
ticIn of H. urrnigera populations to the cotton-
which frequently lay over 500 eggs apiece, and
pr;tdu&rg areas of inland Senegal where the
to the fact that one worm cari destroy several
c:!?p is grown during the July-November rainy
fruits. Graphs showing fosses since 1576 have
searon.
The math causes major losses of
a similar shape each year, suggesting a similar
c:,tton bolls during this period, while damage
pnttern of fbghts of Ii. urmigera.
to tomate plants in the Cape Verde region is
Early results with the new sy-nthetic sex
very slight. With the onset of the dry season -
pheromone on H. urwigera seem promising.
Deccn:ber to June --~-- H. armigeru probably
Pheromone trapping, an easy technique to use
returns t o t h e vegetable areas, particularly
and monitor, provides early and accurate in-
those where tomatoes are grown, and is one
formation on the onset of flights and allows
of the few sources of trop rot during this
initial, low populations of H. urtnigera to be
period. The histogram also shows those periods
detected; SO much SO that one cari say: if
when rhe adult inrects band together -.- prob-
no insects are trapped, no treatment is neces-
-Q+
0
’ -i---- 0
Figure 1. Catch histograrn of the mule Heliothis armigera
108
ll-.--..lll.--l.l.
_“w-.--
-
....v....m.,l-l,-<-
--CII--“------
._.
---
F i g u r e 2 . Chnnges i n tottwtr> faxer f r o m H. armigcra, 1979
sary. Catches should be interpt&ed as early
easily be fitted into a system of integrated con-
warning signais and should help in monitoring
trol at the monitoring station or farm level.
the sprcad of the pest. However, they do not
Since the technique provides more exact in-
directly indicate either the date of or the need
formation about the size of H. armigern popu-
for treatment. For this, data on oviposition,
lations, pesticides could be applied as and
egg hatching and similar factors should be
where needed, making it possible to adapt con-
takrn into account in order to adapt control
trol to Iocal conditions. One cari thus progress
measures to the actual trop situation.
toward carefully planned control as opposed to
The technique of pheromone trapping cari
systematic pesticide application programmes.
References
Corr~~woo~, E.F. & BOCRLXXXHE, L. Tri& with
insuha, Heiiotlris nrmigern. Spotlopfercl liftd-
19X0 Decamethrin for the control of Heliohis ur-
rulis. E n v . Et~tnm~l., 7(l): 3 1 - 3 5 .
migerd on tomaroes in !knegal. Tropicd Pesf
PICC\\RDI, P., CAPIZZI, A., C’ASS.\\NI, G., SPINEUI, P.,
Managemeti!, 2h( 1 !: 3-7.
1977 ARSUR.A, E. & M.es~wm, P. A sex phercmone
GOIWLF, S., KEHAT, M., J.WXSON, M. 6% GAI.UN, R.
component of the old world bol!worm Heli,,-
193 Screeniny phcrornone analogues bv EAG tech-
thir armigertr. 1. Itwcf Phj cio!., 29 1
1
,‘l?):
nique for biological :ictivitp on males of Eariay
1443-1445.
109
(,lt ‘)
*I
_..+a
1
I
--~00*03
%
Study of changes in Heliothis armigera flights with synthetic
pheromone traps in Senegal
L. BOUREXICXHE
Summary
The aldehyde (Z)-ll-hexadecenal was tested with good results as an attractant for the mdle
Heliothis armi~era, the major tomato pest in Senegal. Traps baited with this synthetic iex
pheromone afforded an opportunity io study the activities of the adult moth in tha Cape
Verde region of Sçnegal, a major vegetable-producing area. According to the 1979 finding\\,
this peut was most active durin g the February-April dry season with sharp praks in
mid-February and at the end of March.
During the rainy season (mid-August throu;h
December), it disappeared. Using the pheromone trap technique, control cari now Se
oriented toward planned measures adapted to local conditions as oppowd to sqstema!ic
applications of pesticides.
The tamato math Heliotitis urtnigera (Hiibn.)
The pheromone traps wrre utilizzd through-
(Lqi&~ptera, Noctuidae) is polyphagous and
out the year, beginning in Nobernbrr 1978.
causes substantial losses to various crops in
These are made of two plastic rectang!es joined
Africa.
In Senegal, it is the major tomato
at each corner by rings. The inside of the
pest. causing losses ranging from 10 to 90 per-
bottom rectangle is covered with a sticky sub-
cent accnrding to region or season (Collingwood
stance.
A small rubber capsule saturatrd vcith
and Bourdouxhe, 1980). More detailed knowl-
the synthetic sex pheromone Z-1 1 -C,,:AId.’
edge of thr seasonal activities of these Lepidop-
is attached at the centre of the sticky surface.
tera was necessary in order io organize control
The baited traps were hung from poles 1.25 m
measures and the applications of pesticides
off the ground (higher than the tops of the
whzre and when really needed.
tomato plants) at intervals of at least 50 m.
In 1977 Piccardi et al, (1977) isolated from
They were inspected every day for captured
the abdominal tip of H. armigera virgin fe-
males. The capsule was replaced everq wçek
males a compound that they identifïed as (2,-I l-
and a new coating of the sticky substance was
hsxadecenal. Both laboratory (Gothilf et al.,
applird to the bottom rectangle every ten to
1978; Piccardi et ai., 1977) and field trials in the
15 daqs, as its stickiness waned.
Sudan (Piccardi et ~1.. 1977) have shown this
aldehqde to be a potsnt olfactory stimulant
Resultr and discussion, ne pheromonc proved
for thc male H. m-migmi.
to be highly specific. Despite the presence of
Thz tes: technique ch<>,jen for studying the
numerous other species of maths. only the
changing pattzrn of H. tzrmigmz flights in the
H. urmigercz male was caught.
Cape Verde region of Senrgal was the synthetic
To offset variations in the daily catch sauïed
se3 phc’r~mi)ne trap.
by outside influences, it was decided to use
wetkly total catch figures.
Based o n theqe
klatrrialj and methods. Thc triais wers con-
totals. a histogram (Figure 1) was prq~rsd
ductcd in 1979 at the Centre pour le dévelop-
diagramming the year-long activities of the
pemcnt de l’horticulture about 10 km east of
adult insect and showing thz changing pattrrn
Dakar in the Cape Verde rcgion.
of H. mnziger~z flights in the arca selezted for
the esperiment. The first importsnt catches
in 1979 occurred during the second week of
- - - - -
l Supplied b y Montedi>on.
107
January. There uere two subsequent pcaks
ably to reproduce successive gencratitins. The
of maximum activity: the second week of
main features of the histogram appear to be
Frbruary, -v+ith a peak figure of 65 males
rcpeated for the late i979,‘early 1980 period.
tr,tpped, and the las1 week of March. with 48
.4s in the catch histogram, Figure 2 shows
catches. The time interval between the two
changes in the percentage of tomatoes attacked
peaks of activity corresponds roughly tu the life
by H. amigera.
The tomatoes were picked
c)cie of one generation.
Catches continued
once a week, throughout the year, from un-
to he frequent in April, dropped in May and
treated plots. The percentage of fruit destroyed
became increasingly rare in June and July.
rises rapidly with the onset of flights and well
No catches were recorded between August
before peak catches of adults. This is probably
and mid-December. This is due to the migra-
due to the unusual fecundity of the females,
ticIn of H. urrnigera populations to the cotton-
which frequently lay over 500 eggs apiece, and
pr;tdu&rg areas of inland Senegal where the
to the fact that one worm cari destroy several
c:!?p is grown during the July-November rainy
fruits. Graphs showing fosses since 1576 have
searon.
The math causes major losses of
a similar shape each year, suggesting a similar
c:,tton bolls during this period, while damage
pnttern of fbghts of Ii. urmigera.
to tomate plants in the Cape Verde region is
Early results with the new sy-nthetic sex
very slight. With the onset of the dry season -
pheromone on H. urwigera seem promising.
Deccn:ber to June --~-- H. armigeru probably
Pheromone trapping, an easy technique to use
returns t o t h e vegetable areas, particularly
and monitor, provides early and accurate in-
those where tomatoes are grown, and is one
formation on the onset of flights and allows
of the few sources of trop rot during this
initial, low populations of H. urtnigera to be
period. The histogram also shows those periods
detected; SO much SO that one cari say: if
when rhe adult inrects band together -.- prob-
no insects are trapped, no treatment is neces-
-Q+
0
’ -i---- 0
Figure 1. Catch histograrn of the mule Heliothis armigera
108
ll-.--..lll.--l.l.
_“w-.--
-
....v....m.,l-l,-<-
--CII--“------
._.
---
F i g u r e 2 . Chnnges i n tottwtr> faxer f r o m H. armigcra, 1979
sary. Catches should be interpt&ed as early
easily be fitted into a system of integrated con-
warning signais and should help in monitoring
trol at the monitoring station or farm level.
the sprcad of the pest. However, they do not
Since the technique provides more exact in-
directly indicate either the date of or the need
formation about the size of H. armigern popu-
for treatment. For this, data on oviposition,
lations, pesticides could be applied as and
egg hatching and similar factors should be
where needed, making it possible to adapt con-
takrn into account in order to adapt control
trol to Iocal conditions. One cari thus progress
measures to the actual trop situation.
toward carefully planned control as opposed to
The technique of pheromone trapping cari
systematic pesticide application programmes.
References
Corr~~woo~, E.F. & BOCRLXXXHE, L. Tri& with
insuha, Heiiotlris nrmigern. Spotlopfercl liftd-
19X0 Decamethrin for the control of Heliohis ur-
rulis. E n v . Et~tnm~l., 7(l): 3 1 - 3 5 .
migerd on tomaroes in !knegal. Tropicd Pesf
PICC\\RDI, P., CAPIZZI, A., C’ASS.\\NI, G., SPINEUI, P.,
Managemeti!, 2h( 1 !: 3-7.
1977 ARSUR.A, E. & M.es~wm, P. A sex phercmone
GOIWLF, S., KEHAT, M., J.WXSON, M. 6% GAI.UN, R.
component of the old world bol!worm Heli,,-
193 Screeniny phcrornone analogues bv EAG tech-
thir armigertr. 1. Itwcf Phj cio!., 29 1
1
,‘l?):
nique for biological :ictivitp on males of Eariay
1443-1445.
109