DEVELOPMENT OF A PEST MANAGMENT
SYSTEM FOR BACTROCERA
(CDPT TEPHRITIDAE) IN CRETE BY UTILIZING ECOLOGICAL CRITERIA.
E.N.Psyllakis and N.E.Psyllakis
This paper represents the methodology and some initial results,
during the transitional period from conventional to ecological
olive-oil production, in hilly and plain groves situated in East
Kissamos, Kolimbari area in north-west Kreta. Special attention
was given in improving ecological management of insect pests and
pathogens, especially the Bactrocera oleae pest. Five
thousand trees under drip irrigation, c.v. mainly Koroneiki,
all belonging to a family estate,
were used. For the population monitoring 20 Mc-Phail traps were
hanged while, for the control of the pest Rotenone Derris bait
spraying and a combination of pheromone, olfactory and colour
Deltametrin trap were used.
The effectiveness of the
biotechnical control proved sufficient to suppress Bactrocera
oleae fruit fly population five times less, as an average, when
compared with the integrated treated groves, leading to a High
Quality production index, by preventing and selectively
controlling Bactrocera oleae with the minimum exposure of
the environment to biocides.
Reduction or complete elimination of insecticide sprays for the
olive fruit fly, is possible with a mass trapping system
utilising sex pheromones and food attractants
(G.E. Haniotakis and al) also adequate protection of the olive
crop from Bactrocera olea is possible by mass trapping
with a pest-specific trap under conditions
(T.Broumas and al). Experiments for studying the bio-ecology of
the olive fly were carried out in plains as well as in the
highlands of Creta
(S. Michelakis). The above integrated pest control programs were
used in order to design and implement the ecological management
of Bactrocera oleae pest during 1995 and 1996 in the
Psyllakis olive groves, during transformation from conventional
into biological ones.
MATERIALS AND METHODS
Experiments sites: The
experimental area included 5.000 trees, of which 4.500 are
situated in the Zymbragos area 280-550m high, divided in 15
hilly groves and 500 of them are divided in 2 plain groves,
situated 200-250m high northern in the Nochia area, both areas
in the Kolymbari region.
In the Zymbragos groves the majority of the trees are of the
“Koroneiki” c.v and only one percent of the “Tsounati” c.v. The
Nochia groves are consisted only of “Koroneiki” c.v. The
majority of the trees are between 25 and 75 years old and the
distances between them is around 7 meters. Approximately 20% of
the trees are with 3 legs. Levelling of land within highland
groves varies and is mostly more than 15%.The whole olive grove
is under drip irrigation and has been divided in 5 replications,
the first one belonging to the Nochia grove. For the year 1995
ecological pest management was done by the use of traps and
Rotenone Derris bait spraying.
Vioryl traps are like green envelope rectangles, covered with
deltametrine at a concentration of 0,15%.Attractants:Traps were
baited with one pheromone dispenser containing 0,080gr of
pheromone and with one ammonia releasing dispenser-the whole
green envelope- perforated, and containing 70 gr. ammonium
bicarbonate salt, as well as with the specific green colour of
the envelope paper. Trap installation: In the beginning of June
2800 Vioryl traps were installed and on the mid of June 200 of
them were installed additionally in sites where population
density was high. Traps were placed one in every other tree at a
north orientation at an inside point of the canopy. From 6-9
September the above operation was repeated but traps were hanged
at an east orientation. Also, ground bait sprays were done with
Rotenone solution,10% active compound,2% protein hydrolysate (Dakus
Bait 100) and 2,5% of sugar.
Additionally there were done four
(in Nochia) and five (in Zymbrayos) ground bait sprays in
neighbouring olive trees with a solution of 2% proteine
hydrolysate (Dakus Bait 100) and 0,6% fenthion, in order to
isolate the ecological groves.
A network of 20 McPhail-traps,17
for the four replications, in the 8 bigger irrigated ecological
groves in Zymbragos were installed immediately after the Vioryl
ones and 3 in the Nochia.
As control the rest of the olive
groves in Zymbragos with 80.000 and in Nochia with 30.000 trees
were used. In the first, 7 ground bait sprays (2% protein and
0,6% fenthion) were done by the Kolymbari union, but 6 in Nochia
with 2 additional ones focused only in sites with high
For the year 1996 ecological
management of Bactrocera oleae pest changed in order to
reduce or eliminate the Rotenone Derris bait spraying as well as
isolating with preventive bait sprays.
In the same 5 replications during
the first five days of June 3.000 Vioryl traps were installed in
the ecological grove, additionally 1000 Vioryl traps without
pheromone dispensers were used in order to isolate the
ecological grove. The same procedures, as described for
1995,were done in the control area during 1996.To establish
fruit infestation levels, fruit samples were picked at the end
of each month from 10 olive trees from each replication,25
fruits were picked at the head height from each tree.
For monitoring pest population
changes the Zymbragos control area has been divided into 2
subgroups: one with McPhail traps in a distance until 100m. from
the eco-olive grove and the other with McPhail traps in a
distance bigger than 100m.
Results and Discussion
A general characteristic of both
subgroups is the high population density comparing with the
eco-ones but this difference is quite smaller in the nearer
traps.Figures1,2 and 3,4 shows population curves for Nochia and
Zymbrayos respectively. For Nochia the F test has been proven to
be significant during 1995 and 1996 at a p<0.01.For Zymbrayos
mean separation by Duncan’s Multiple Range test at p<0.05 was:
Integrat. Near Traps
Integrat. Far away traps
Rotenone Derris applications
doesn't seem to have the desired effect comparing with the
control on population density, throughout the olive growing
As it can be seen from the
figures, fruit infestation is smaller in the control with
respect to the ecological olive groves. The fruits of all
replications of the eco-olive grove were plumper and more open
to attack, due to the crop irrigation conditions. In Zymbragos,
the low fruit infestation levels during August and September
were also due to the arid conditions of the whole control area.
In Nochia half of the control is under drip irrigation and with
regard to its rather small fruit size had low fruit infestation
levels due also to the additional sprays. For both summers
(1995-1996) weather conditions were quite favourable for the
development of the fruit fly population due to the absence of
the usual high temperatures during July and August
(The mean max temperature for the decade 1971-1980 were
36/36/34/34/31 for the months June, July, August, September and
October with a Sn-1 2.2/2.6/2.3/3/2.1 and a cv
(%) 6.2/7.2/6.8/8.8 and 7)
During 1996 olives gained weight
quicker so they were more quickly infested than 1995 which has
been an on crop year, nevertheless due to the efforts in order
to control the alternate bearing differences in yields between
an on and off crop year are around 20%. The E.M.I.P. achieved
the desired results in Q.P.I. (Quality production index) and
E.E.B.( Effective Exposure to Biocides) because the produced
eco-olive oil achieved a very low acidity from 0,3 to 0,5.Even
if E.E.B. is very low, we do use a selective pesticide in the
traps in order to control Bactrocera-oleae.
Haniotakis G. E., M. Kozyrakis,
K. Bonatsos. Area wide managment of olive fruit fly by feeding
attractants and sex pheromones on toxic traps.P.549-560
S. E. Michelakis.
Bio-ecological data of the olive fly(Dacus
oleae (Gmel)) in Crete Greece.P.397-406.
T. Broumas, G. Haniotakis.
Further studies on the control of the olive fruit fly by mass
Fruit flies: Proceedings of the
second international symposium 16-21 September 1986, Colymbari,
F. Florelli. Deltametrin and
environment. Proceedings of the second national entomological
symposium Athens1989 P.160-171.
Stavroulakis, A. Nikolaydis, A. Kalaitzaki and S.
Michelakis The use of Rotenone against olive fly (Bactrocera
oleae Gmel) Third ENOF workshop:"Resourse use in organic
Farming" Ancona 5-6 July,1997.
We also have the diagrams - if
interested contact us.