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Entomology and Pathology of Lebanese Forests

Dr. Dany El-Obeid

2016

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Forest and Insects

1. Importance of insects in forest ecosystem

2. Major Lepidopterous defoliators of lebanese forests

3. The case of Cephalcia tannourinensis

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1- Importance of Insects in

Forest Ecosystems

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Ecosystem

• An ecosystem is a natural unit consisting of all plants, animals and microorganisms in an area functioning together with all the non living physical factors of the environment.

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• Communities of living things: plants, animals, microbes, etc

• Non-living things: rocks, soils, gasses, etc

• all the elements forming this ecosystem interact and are interdependent.

• Organisms are surviving continuously by natural selection, reproduction and dispersal behavior.

Ecosystems consist of…

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Ecosystem examples

Desert Coral reef

Human ecosystem Rainforest 6

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Forest ecosystem

• Forest is an ecosystem in which trees predominate.

• They create a special microclimate.

• They consist of large and small trees, shrubs, herbaceous plants and cryptogams.

• They are a habitat of millions of species.

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• Forest ecosystem consist of diverse and complex processes and interactions between each trophic level.

• A main process is the energy transformation.

• Solar energy is transformed into chemical energy by photosynthesis and it flows through the ecosystem via a food web. Some energy is always lost in each transfer from a higher trophic level via respiration and as heat.

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• The transformation of energy in an ecosystem starts with the input of energy from the sun:

- trees and green plants are “primary producers”

capture the sun’s energy and light for photosynthesis.

- herbivores are “primary consumers” they consume plant products and acquire their energy.

- carnivores are “secondary consumers” they eat the herbivores. - detritivores are “decomposers” they feed on droppings and carcasses.

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Importance of insects

• Forest ecosystems harbor a very large diversity of insect species.

• This abundance and diversity make insects play a major role in the functioning of the forest ecosystem.

• The importance of insects in forest ecosystems depends on their abundance, biomass, consumption behavior and interaction with other organisms.

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• Major roles of insects:

1. Insects may affect the ecological successions and evolution

of ecosystems by:

- modifying the intensity of competition between plant species.

- eliminating certain species.

Eastern tent caterpillar attacking and reducing the number of prunus sp. 12

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2. Insects may affect the population dynamics in forests by consuming a proportion of flowers, fruits and seeds

jeopardizing the regeneration of trees.

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3. Insects may have a mutualistic relationship/interaction with forest trees

Both the insect and the host tree receive a benefit from this interaction

Pollination of trees by insects

Trees produce nectar as a food source for insects

Insects transport pollen to other trees.

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4. Insects have a major role in the decomposition of organic matter and in the carbon recycling process.

In a balanced forest ecosystem, many insects speed up the death and

decomposition of injured, weak or aging trees.

Insects participate in the forest's renewal, which is part of the natural succession process in forest ecosystems.

Decomposition is the last stage in the ecological cycle, when basic elements return to the soil or to the atmosphere and are once again available to plants.

Forest litter

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5. Insect pests may kill trees or slow their growth significantly in the case of an outbreak.

Type of damages: deterioration in the useful quality of wood ex: longhorn beetle

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Loss of production due to reduced growth of trees as a result of repeated defoliation.

Defoliation lowers a tree’s resistance and reduces photosynthesis and the development of reproductive organs which may impair regeneration.

Many defoliating insect species exist in forests in Lebanon:

- Thaumetopoea wilkinsoni (pine processionary moth)

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Damage by gypsy moth

- Lymantria dispar (gypsy moth)

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Insects can be vectors of viruses or pathogenic fungi.

1. Vector of viruses:

Elm phloem necrosis, which is a viral infection, is transmitted by the bites of the leaf hopper Scaphoideus luteolus.

White-banded elm leafhopper

Symptoms 20

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2. Vector of pathogenic fungus:

The sap beetles, nitidulid beetles, which live on sap exudations, propagate spores of the fungus Ceratocystis fagacearum causing the oak wilt disease.

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6. Some insect species may play a very crucial and vital role concerning the control or limitation of certain other severe insect pest of forest trees.

Insects as predators and parasites 1- Predators:

will consume many pest insects during their development

are generally larger and faster than prey

male and female of the immatures and adults can be predators

have a broad host range

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2- Parasites:

have an immature life stage that

develops on or within a single insect host ultimately killing the host

only the female searches for host

specialized in choice of host

adult parasites are free-living

most beneficial insect parasites are

wasps or flies.

Endoparasites

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Trichopoda pennipes (fly) eggs on squash bug host.

Ectoparasites

Parasitic eggs on head of caterpillar 24

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Major Lepidopterous

Insect Pests of Forests

in Lebanon

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Outline

1. Distribution of forests in Lebanon.

2. Major Lepidopterous insect pests of pine trees in Lebanon.

3. Major Lepidopterous insect pests of cedar trees in Lebanon.

4. Major Lepidopterous insect pests of oak trees in Lebanon.

5. Management practices

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Distribution of Forests in Lebanon

• According to FAO, the statistical values of 2005 are:

• Forests are estimated to cover 13.3 % of Lebanon.

• The majority of the forest area is covered with oak trees and which make up 60 % of the total forest area (40 000 ha).

• Pine trees cover 17 000 ha of the total forest area and only 5 400 ha are covered with the type of pine trees which give fruit bodies on which some rural communities depend on for income.

• The cedar forests only make up 2.5 % of the total forest area which consists of an area of 2 000 ha.

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• Cedars: • Dichelia cedricola ( the cedar shoot moth) • Thaumetopoea libanotica (cedar processionary moth).

• Pines: • Thaumetopoea wilkinsoni/pityocompa (pine processionary moth). • Rhyacionia buolina ( pine shoot moth).

• Oaks: • Lymantria dispar (gypsy moth).

Major Lepidopterous Insect Pests

of

Forest in Lebanon

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Classification

• All the Lepidopterous insect pests mentioned belong to:

• Kingdom: Animalia.

• Phylum: Arthropoda.

• Class: Insecta. • Order: Lepidoptera.

• These pests belong to different families, genus and species.

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The Pine Processionary Moth

Thaumetopoea

wilkinsoni/pityocompa

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The Pine Processionary Moth

• Classification:

• Family: Notodontidae

• Genus: Thaumetopoea

• Species: wilkinsoni/pityocompa

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The Pine Processionary Moth

Description:

• The larvae in the first instar is greenish in color.

• At L2, the larvae becomes darker in color and it adopts its definitive appearance starting L3.

• The larvae is a 30 to 40 cm caterpillar, dark brown in color with reddish line on the back.

• Its body is covered with irritant hairs. • The adult insect is a grayish moth with

2 parallel dark bands. 32

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The Pine Processionary Moth

• Life cycle:

• The emergence will take place at night

during which the male and female will mate.

• Adult moth usually lay their eggs on pine needles starting from the bottom, working their way up.

• The hatching or blossoming of these eggs will take place 5 to 6 weeks after the laying.

• The larval stage consists of 5 instars (L1…L5)

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The Pine Processionary Moth

• The L1 and L2 caterpillars will start attacking pine needles.

• Mutation and change in color will take place for each larval instar.

• At the third larval instar, the caterpillars will form a nest in which they will remain all the winter season.

• At the beginning of spring, the caterpillars will get out of the nest.

• At L3, the hairs will appear on the caterpillar’s body.

• The L3, L4 and L5 will continue mutating and attacking branches and needles.

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The Pine Processionary Moth

• At the end of L5 stage, the caterpillars will move in “procession” to search for a soft and warm soil to settle in for pupation.

• The pupae usually emerges at the beginning of summer but it can also remain in the soil up to 1, 2 or 3 years.

• The emergence is influenced by the altitude and temperature.

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The Pine Processionary Moth

• Damage:

• The pine processionary moth is an important defoliator of Lebanese forest trees. • It causes: - Defoliation of forest trees. - Death of forest trees. - Weakening of forest trees which make them more susceptible to secondary infections

and attacks of other pests. - Deformation of branches. - Irritation and severe allergic reaction in humans and animals.

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The Pine Shoot Moth

Rhyacionia buoliana

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The Pine Shoot Moth

• Classification:

• Family: Tortricidae.

• Genus: Rhyacionia

• Species: buoliana.

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The Pine Shoot Moth

• Description:

• Larvae are pale yellow-brown to brown and have black head capsules and thoracic shields.

• Adults are a medium sized moth: - light orange-red forewings with irregular silvery spots.

- gray hindwings.

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The Pine Shoot Moth

• Life Cycle:

• The pine shoot moth has 5 larval instars. • This pest overwinters as a partially grown

caterpillars, at the L3 stage, in silk-lined cavities eaten into pine buds.

• When the conditions are suitable, around the month of April, the caterpillar will leave the silk cavities and resume feeding on pine shoots.

• The larvae finishes its development approximately at the end of May (L4 and L5) by feeding on new shoots and buds.

• The next stage is the formation of a pupal cell made within a bored shoot. 41

The Pine Shoot Moth

• After 3 weeks, an adult moth emerges.

• After a short period, the adult male and female will mate and the eggs will be laid at the needle base and on the bark of new and old shoots of forest trees.

• 10 days later, a small caterpillar will appear and starts burrowing into the needle bases (L1 and L2)

• At the end of the summer, the caterpillar will tunnel into a newly formed pine bud and form a web coating at the entrance hole stop all activities, remain dormant till the next spring.

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The Pine Shoot Moth

• Damage:

• The young larvae can kill pine needles and small buds which do not expand in spring.

• The intermediate larvae can kill buds when preparing for their overwintering stage.

• The mature larvae causes the most extensive and serious damages:

- kills larger developing buds which curl and form a permanent crook.

- kills elongating shoots which wilt and turn brown.

- heavy infestations result in rounded trees with very stunted growth and deformed branches and shoots.

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The Cedar Processionary Moth

Thaumetopoea linbanotica

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The Cedar Processionary Moth

• Classification:

• Family: Notodontidae.

• Genus: Thaumetopoea.

• Species: libanotica.

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The Cedar Processionary Moth

• Description:

• The mature larvae has very long hairs

on the dorsal part with a grayish

body. • The adults of the cedar processionary

moth are smaller in size than the pine processionary moth.

• Their hindwings are white in color and they are lighter in color than the pine processionary moth.

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The Cedar Processionary Moth

• Life Cycle:

• The overwintering stage of this pest is in the form of eggs.

• The cedar moth doesn’t form a nest at any stage of its life cycle.

• The eggs are laid on the branches, not on the needles.

• At the beginning of spring, the L1 emerges and the 4 remaining instars will follow.

• At the end of the spring season, the L5 will enter the soil for their pupal stage.

• The adults will emerge when the right conditions are present (e.g. temperature)

• Mating will occur in the first night after emergence.

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The Cedar Processionary Moth

• Damage:

• As for the damage of the cedar processionary moth, it can be visible and serious only if the insect is present in a very high number which is not the case in Lebanon.

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The Cedar Shoot Moth

Dichelia cedricola

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The Cedar Shoot Moth

• Classification:

• Family: Tortricidae

• Genus: Dichelia

• Species: cedricola

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The Cedar Shoot Moth

Description:

• At the L1, L2 and L3 stages, the larvae is

light in color.

• At the last 2 stages in its larval period, the caterpillar becomes greenish in color.

• As an adult, the male and female are very similar in shape and color, but the female has usually a larger abdomen.

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The Cedar Shoot Moth

• Life Cycle:

• Adults of Dichelia cedricola emerge at the beginning of summer, around the month of June.

• The eggs are deposited on the needles. • This pest has 5 larval instars. • L1 and L2 penetrate into needles for

feeding and then they attack cedar buds. • The caterpillar spends the winter in its L3

stage between 3 to 4 joined needles. • In spring, L4 and L5 will continue their

feeding on needles causing great damages.

• The caterpillar will change to a pupae before the month of June and will settle between the cedar needles.

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The Cedar Shoot Moth

• Damage:

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The Gypsy Moth

Lymantria dispar

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The Gypsy Moth

• Classification:

• Family: Lymantriidae.

• Genus: Lymantria.

• Species: dispar.

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The Gypsy Moth

• Description:

• Newly hatched larvae are black with long hairs.

• Older larvae also have long hairs, and five pairs of blue spots and six pairs of brick-red spots along their back.

• The adult female gypsy moth is white with dark wing markings.

• The adult male is olive-brown with dark wing markings.

• The female has a heavy body and rarely flies, despite well-developed wings.

• Although the male is a powerful flier, he has much smaller body and wings than the female.

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The Gypsy Moth

• Life cycle:

• The overwintering stage of the gypsy moth is in the form of egg masses laid on the underside of branches, in tree trunks, under dead barks...

• Newly hatched larvae emerge in the beginning of spring warming.

• They do not build nests, they hang from leaves and branches by their own silk thread which enables them to be carried by wind and ensure their spread.

• The male has 5 larval instars while the female has 6 which is needed for the nutrient demanding process of producing eggs.

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The Gypsy Moth

• At the beginning of the summer, the caterpillar sheds its last larval skin to form a pupae.

• After approximately 2 weeks, the adult moth will emerge, ready to mate. • The females will give off strong sex pheromones to attract males which have very

broad, feathery antennas capable of detecting these pheromones from considerable distances.

• Males are very strong fliers and are capable of mating with several females. • The only function of adult moths is to mate and lay eggs, they do not feed.

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The Gypsy Moth

• Damage:

• The caterpillar is the damaging stage of the gypsy moth. • The larvae eats tremendous amounts of leaves causing

serious damages and defoliation. • The defoliated trees are very susceptible to diseases and

other attacks by insects. • Consistent defoliation over several years can lead to tree

stress and death. • The gypsy moth has a wide host range and a great capacity

to increase in number.

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Management Practices

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Management Practices

Mechanical method:

In the case of the pine processionary moth, a method would be:

- removing the nests during winter season ( should be careful to be protected from any contact with the irritant hairs).

This method is used in some regions like Aley where the municipality cuts

off the nests to reduce the number of Thaumetopea. In the case of the gypsy moth, a mechanical method would be: - removing any pupae found in shoots, on leaves, in tree bark… The mechanical method can only be applicable and useful in small

peripheries or areas with young forest trees of low heights and with low population density.

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Management Practices

Chemical method:

- Insect Growth Regulator: an effective and used method in Lebanon is the application of diflubenzuron

(IGR). It can act on the different larval stages and prevent them from mutating.

- Mating disruption: males detect the sex pheromones emitted by females using receptors on their

antennas. Mating disruption consists of preventing males from finding the females for mating by disrupting the male’s receptor with pheromone powder (this method is not used in Lebanon, forest areas are small)

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Management Practices

• Lure and kill:

• mixing sex or aggregating pheromones with insecticides placed in

containers. Consequently increasing the efficiency of chemical control and reducing environmental pollution.

• Pheromones can also be placed on a metal platform with sticky material to trap the moth.

• But this method is used more as a monitoring method rather than a control method.

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Management Practices

• Biological control:

• Bacillus thuringiensis: The best time to spray with Bt is just after egg hatch.

The young larvae are much more susceptible to Bt than older and larger ones.

This is the only biological control method used in Lebanon. It has achieved satisfactory results.

• Entomophaga maimaiga:

when infected with this fungus, the gypsy moth larvae die hanging vertically from tree trunks with prolegs extended laterally (this method is not used in Lebanon).

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Management Practices

Female adult of Blepharipa pratensis

parasitizing a a gypsy moth caterpillar. This is a parasitoids used as a biological control but not in Lebanon.

Calosoma beetle is an important biological control, it is a predator mainly on Thaumetopea and the gypsy moth, it is present naturally in forests in Lebanon.

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Monitoring Tools of Cephalcia

tannourinensis and Entomofauna of

Lebanese Cedar

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OUTLINE

Studies on Cephalcia tannourinensis Chevin

Life cycle and behavior

Population dynamics and Monitoring (UNEP Project)

Management Program

Pheromones (UNEP Project)

Diapause

Natural enemies

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Geographic Distribution of Cedrus

genus in the Mediterranean region 71

Tannourine

Maaser El Shouf

Barouk

Ain Zhalta

Bsharry

Kammouaa

Suwayssi

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1998-1999

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1998-1999

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1998-1999

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Emergency Situation

- Cedars are

dying!

- What to do?

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What is causing the cedar decline???

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Cephalcia tannourinensis Chevin 80

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Cephalcia tannourinensis Chevin 81

April July June May

August ……. ……. ……. …….. January Feb. March

Life cycle of the cedar

web spinning sawfly 82

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Insect Growth Regulator:

Diflubenzuron,

environmentally friendly

Year 2000

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2001, 2002 and 2004

Lebanese Army Helicopter

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Conclusions

• Outbreak was due to the change of temperature when the larvae penetrate the soil where an increase of 0.5oC above 12oC can lead to the development of annual year diapausing individuals.

• What happened since 1994 was a gradual increase of the average temperature which lead to the outbreak situation in 1998-2000 which was suppressed by the use of insecticides. The outbreak would persist if no measures were taken and the return to outbreak situation is not to exclude with the prevailing climatic factors.

• Whether the temperature change or global warming is due to the Earth changing rotational axis or to environmental pollution the result is the same

• an increase of the temperature is the cause of the outbreak of the webspinning sawfly.

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1999 88

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Population Dynamics &

Management Program

Information about insect population could be

a very useful component of stand dynamics

because they affect stands in a number of

ways.

Two aspects: Distribution and Abundance

AUB, FAO, MoA, LU 90

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Monitoring Techniques

• Soil Prepupae Sampling

• Yellow Sticky Traps

• Malaise Traps

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40 x 40 cm sample

Depth up to 50 cm

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• Soil Prepupae sampling

– Accurate method but costly in time and labor

• Yellow Sticky Trap

– When population is very low it does not, catches were not correlated with soil Prepupae sampling

– Very easy method to use

• Malaise trap

– Not recommended

Traps Efficiency

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Nov.02 Nov.03 Nov.04

pronymph

eonymph

Tannourine 1998-2004

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pronymph

eonymph

Hadath El Jebbeh 1998-2004

Control areas

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Pheromones

Why looking for pheromones?

No pheromones for any Cephalcia genus

have been yet identified

Preliminary Results indicate an Attraction

Analysis confirms the results

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Females produce pheromones

Males are always found swarming around females

Males are attracted by traps containing virgin females

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2 4 6 8 10 12 14 16 18 20 22 min

1

2

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males

females

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Pheromone Monitoring

• Put the pheromone traps starting mid april

• Hang the trap at 2m height inside the tree canopy

• Always select a tree which is not exposed to wind

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Diapause

Prolonged state of arrested development

Cephalcia tannourinensis passes the diapause as a prepupae

Prepupae are divided into two groups

Those that have a diapause extended over several years

Those with a diapause of several months

Factors influencing the diapuase

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Natural Enemies

Ant Species

Beauveria sp. detected By Allard

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