6
7
Ιn the frame of plant protection against the olive insect pests in the pilot areas of the project, the main
pests recorded were the olive fruit fly Bactrocera oleae in Crete, and the plant bug Closterotomus
trivialis, the curculionid Rynchites cribripennis and the olive fruit leaf moth Palpita unionalis in Trifylia
whereas the olive moth Prays oleae caused damage only in a few cases in the three areas. Guidelines
for IPMof olive insect pests, samplingof natural enemieswere preparedbyBPI andAUAentomologists
for the collaborating agronomists, who were also trained in the relevant monitoring and sampling
methods. The population levels of the pests were monitored by the collaborating agronomists and
guidelines for spraying applications were given to growers when necessary according to the IPM
Guidelines. For example, the close monitoring of the flight of the olive moth (pheromone traps) and
fruit damage (fruit sampling) revealed that sprayings were very seldom required.
Environmentally friendly techniques were applied and evaluated aiming at the most appropriate use
of biodiversity in pest control. In this way, the damage severity of the insect Cloterotomus trivialis was
associated with the presence of certain weeds in the olive orchards. The timely cut of the weeds was
shown to be a promising cultural technique in the control of this pest.
In the region of Merambello, Crete, the outbreak of the olive leaf midge in spring of 2012 was
controlled by a native parasitoid which succeeded population 2013, indicating the importance of local
fauna in pest control. The parasitoid was found after samplings of olive twigs, whereas insecticide
applications, which could be possibly harmful to the parasitoid, were avoided.
The olive fruit curculionid Rhyncites cribripennis, was found to damage less the main olive variety
grown in Trifylia, ‘Mavrolia’ compared to the variety ‘Koroneiki’. The population of the olive moth
Palpita unionalis reached high levels in Trifylia in 2011 but sprayings were suggested only in a few
cases according to the damage levels.
Samplings of soil beneficial arthropods proved the presence of several species of spiders and
Carabidae beetles, mostly in Trifylia (29 species) and secondly in Peza (19 species) and Merambello
(15 species), which can contribute to the control of the larvae of the olive fruit fly and the olive fruit
curculionid. In addition, the presence of mites, which can be useful as bioindicators of changes in soil
properties and impact of human activities, was recorded and differences in the number of mite species
were found in relation to the different weed management practices in the olive groves. The number of
mite species of the Order Cryptostigmata (Oribatida) was larger in the olive groves of Merambello and
Peza, where mechanical or chemical control of weeds was limited, compared to Trifylia where weed
control was performed in most olive groves.
Natural enemies in the olive tree canopy included spiders (Araneae), predatory bugs (Anthocoridae,
Miridae), lacewings, Coccinellid predators, Syrphids, Hymenoptera parasitoids and predatory mites. A
total of 21 species of predatory mites from 9 Families were found with the majority of them belonging
to the Familiy Phytoseiidae. Myrambelo had the greatest species diversity and Trifylia had the smallest
one. The majority of the predatory mites found in the areas of Crete were common and are different to
the ones found in Trifylia. The dominant species were different in each area.
Weeds & olive cultivation
Integrated Weed Management is a system that includes various weed management strategies, which
should be as economic as possible for the producer and friendly to the environment. A prerequisite
for future suggestions and establishment of a specific management program in an area is the very
good knowledge of the existing situation with regard to the native plant species in olive groves. Weed
population monitoring in the three pilot project areas and correlation of the findings with crop and
environmental parameters such as type of soil, irrigation, organic farming, ways to manage weeds
(herbicides, mowing), spatial distribution of weed species etc. were conducted by BPI. The approach
followed for the achievement of the objectives of the programwere (a) training of local agronomists and
olive growers in target areas on methods of integrated weed management and b) sampling of native
flora to capture and assess the situation as regards the land cover of the olive groves. The ultimate
goal was the adoption of the instructions issued by the agronomists in collaboration with the experts on
good practices related to herbicide applications, training of growers on weed management techniques
and tools, with the aim to minimize the environmental footprint. The latest was assessed by either the
IAP Method or from analyses of soil samples for the determination of residues of the active substance
glyphosate (the dominant active substance used in all areas) and its metabolite AMPA. Indicatively, 45
different weed species were identified in Peza Region, 42 in Merambello and 93 in Chora Trifilias.
Weed species have developed resistance to glyphosate
Long history of sole glyphosate application, without any other integrated management methods, has
made significant changes in the weed flora in olive orchards in the region of Chora Trifilias. Species
of the horseweed family (Conyza canadensis and C. bonariensis) have been the most frequent weed
species that developed resistance to glyphosate in various parts of the world, including Greece. In
order to document resistance, 54 seed samples of those species were collected from specific sites
with a known history of weed control methods. Raised plants in the greenhouse and laboratory, were
subjected to: a) dose-response experiments; b) biochemical screening test (measurement of shikimate);
and c) molecular studies. It is documented that in a significant number of locations, populations of
the above weed species have developed resistance to glyphosate. In addition, in a field experiment, it
was sown that at twice the label recommended (720 g a.i. per ha) glyphosate rate, horseweed species
were resistant to this a.s. Local farmers and consultants were trained by experts for adopting more
sustainable weed management strategies.
Pesticide residues
The implementation of the SAGE10 project included analysis of groundwater and surface soil samples
for determination of pesticide residues and assessment of the environmental impact to the target areas
from these contaminants.
Sixty-nine (69) groundwater samples fromthe three regionswere collected between 2011 and 2013.
In addition, 175 samples of surface soil were collected from selected parcels of Chora Trifilias
Plant
Protection:
Pest and Weed
management
Soil beneficial arthropods and spiders
in Chora Trifylias, Peza and Merambello
in 2012.
Application of glyphosate in Chora Trifylias
Collembola 76 είδη
Opiliones 10 είδη
Chilopoda 6 είδη
Staphylinidae 12 είδη
Carabidae 100 είδη
Araneae 208 είδη
CHORA TRIFILIAS
PEZA CRETE
MERAMBELLO CRETE
Collembola 579 είδη
Opiliones 44 είδη
Chilopoda 28 είδη
Staphylinidae 65 είδη
Carabidae 68 είδη
Araneae 266 είδη
Collembola 134 είδη
Opiliones 8 είδη
Chilopoda 13 είδη
Staphylinidae 20 είδη
Carabidae 36 είδη
Araneae 120 είδη
