Persistence of the entomopathogenic fungus Lecanicillium muscarium Zare & Gams under ambient conditions in the field.

Positive results of laboratory trials, which proofed the effectiveness of the entomopathogenic fungus L. muscarium against endophytic larvae of the horse chestnut leafminer moth Cameraria ohridella DESCHKA et DIMIC, led to outdoor trials. One aspect of these trials was to determine the persistence of the fungus, which was used as commercial product Mycotal (Koppert, NL) and as strain V24 from the section Phytomedicine. In different variants several spore concentrations and the influence of an oil-containing adjuvant (Koppert, NL) were tested. The persistence of the fungus was determined through the number of colony forming units (cfu) after impressing the leaves on agar plates. The fungus could be detected until 14 days past application (dpa), with differences between the variants, despite most unfavourable weather conditions, like above-average of temperature and hours with sunshine as well as low humidity and heavy rainfall. In all variants were found dead and moulding larvae within the mines.

Soil application of Beauveria bassiana to control Ceratitis capitata in semi field conditions.

The Mediterranean fruit fly Ceratitis capitata (Wiedemann) is a highly polyphagous pest of economic importance cultures in Syria, as in many other parts of the world. The potential of the entomopathogenic fungus Beauveria bassiona BALS (VUIL.) strain 412 against adults of Mediterranean fruit fly C. capitata was evaluated in semi field conditions during the summer. Soil (5-7 cm high) was filled into plastic container (27 cm x 32 cm). In one container 75 pupae, two days before emergency, were spread uniformly on the soil. Then the pupae were covered with soil (4-5 cm layer). After that, 30 ml suspension of fungal spores (4 x 10(8) spores/ml) was applied to the soil surface using a dash bottle. This corresponded to a spore density of 1.3 x 10(7) spores/cm2 on soil. Water and food (1:4 yeast, sucrose) were placed in the cages for the emerged flies. The semi-field evaluation of B. bassiana revealed a fly mortality of about 46% compared to 16% in the control. In addition 72% of dead flies were moulded in the treatment. These results indicated that the entomopathogenic fungus B. bassiana was pathogen against the adults of C. capitata not only in the laboratory condition but also under field condition. That means B. bassiana could decrease the offspring of C. capitata. Therefore B. bassiana could be an effective factor to control C. capitata in combination with other control methods, used in IPM program in the field.

Behavioural response of Phytoseiulus persimilisin inert materials for technical application.

A large scale application of the predatory mite Phytoseiulus persimilis Athias-Henriot for use in the biological control of spider mites in the field requires testing the behaviour of Phytoseiulus persimilis in inert materials, like millet pelts and Vermiculite (1-3 mm). In laboratory studies, the distribution of the individuals in such materials, the time of remaining in the material were proved. To examine the abiotic influences on the time of remaining in the material, the dampness of the materials was varied (0%, 5% and 10%). Moreover, the influence of attitude of materials was tested. The time of emigration from the material was noted for each individual. Emigration from all dry materials was completed 15 minutes at the latest after set up of the mites. The increase of dampness had an obvious effect on the time of remaining in the material. In this respect the material millet pelts showed the most favourable effect with 10% dampness. Increasing attitude of material the mobility of predatory mites will be influenced negatively above 75 cm. Up to 50 cm, mites have not a problem to move in the material and the time of remaining can be prolonged considerably.

Effect of the entomopathogenic fungus Lecanicillium muscariumon the predatory mite Phytoseiulus persimilis as a non-target organism.

In biological control, different benefit organisms have to combine for an effective management. If entomopathogenic fungi will be integrated, than it has to be considered also the effect on non-target organisms Like beneficial arthropods. Because of the high importance of predatory mite Phytoseiulus persimilis in biological control it was to determine side effects of Leconicillium muscarium on this species. In two standardised biotests in petri dish and on plants (P. vulgaris) individuals were dipped in suspension or set down on leafs after spraying with L. muscarium at different spore density. Results indicate pathogenicity for the predatory mite in principle. But the dimension of infection risk decrease, all the more conditions approach to practical sequence. Under practical conditions on plants and in practical relevant concentration of 10(6) and 10(7) sp./ml no risk is to expect on the plant.

Susceptibility of Ceratitis capitata Wiedemann (Diptera: Tephritidae) to entomopathogenic fungi.

The Mediterranean fruit fly Ceratitis capitata (Wiedemann) is one of the most serious pest of fruits in Syria and present all year round. This fly is active on different host plants, such as mango, peach, fig, apple, pear, and citrus. The number of generations per year varies with local temperatures and host plant. The objective of this research was: to evaluate the pathogenicity of entomopathogenic fungi on adults of C. capitata under laboratory conditions. Flies for experiments were obtained from a population reared in Laboratory conditions at 25 +/- 2 degrees C, 70 +/- 2% RH, and a photoperiod of 16:8 [L: D] h. Four concentrations (3 x 10(4), 3 x 10(5), 3 x 10(6), 3 x 10(7) conidia/ml) of Beauveria bassiano (Balsamo) and Paecilomyces fumosoroseus (Wize) were tested on adults of C. capitata less than 3 days old. The flies were inoculated with spores by dipping them for 10-15 seconds in 10 ml of conidial suspension or water for control respectively. After that, flies were transferred to plastic cages with diet and water. There were 10 flies per cage and 4 replicates per concentration. Adults of the Mediterranean fruit fly, C. copitata, were high susceptible. In case of B. bassiana 100% of flies were dead at 3 x 10(7) conidia/ml and 82.5% at 3 x 10(6) conidia/ml. For P. fumosoroseus the mortality of flies was 70% at 3 x 10(7) conidia/ml and 62.5% at 3 x 10(7) conidia/ml. However, in low levels of concentration (3 x 10(4) and 3 x 10(5) conidia/ml respectively) only 7.5% and 30% flies died. Mouldiness of the dead flies ranged from 77.5% to 72.5% for the two higher concentrations (3 x 10(7) and 3 x 10(6) conidia/mt) of B. bassiona and 52.5% for P. fumosoroseus at 3 x l0(7) conidia/ml. The fungal mycelium of both entomopathogenic fungi emerged through the soft parts of the exoskeleton, such as the wing bases, legs bases, head and membranous regions of the abdomen. In case of B. bassiana additional the ovipositor was mouldy.

Pathogenicity of entomopathogenic fungi on hibernating pupae of Cameraria ohridella Deschka & Dimic 1986 (Lepidoptera, Gracillariidae). Part 2: Efficacy of entomopathogenic fungi against pupa in her pupal cell.

The naked pupae of chestnut leafminer Cameraria ohridella are susceptible for entomopathogenic fungi Paecilomyces fumosoroseus strain P6; Lecanicillium muscarium strain V24; Metarhizium anisopliae strain M72 and Beauveria bassiana strain B412. Their activity at low temperature is advantageous especially for the use in the winter season. (Richter et al., 2007a). Therefore the possibility of infection should be examined in biotest for pupae in their pupal cells on leaf of chestnut at conditions Like in winter. Efficacy of entomopathogenic fungi is decreased, if pupae are in their pupal cells. But fungi, especially L. muscarium, proved the ability to infect pupae of C. ohridella in their pupal cells. Infected pupae moulded in their pupal cells after application. Infection doesn't come from spores. In semi field trials with L. muscarium 60% of pupae were infected in their pupal cells and died after incubation with mouldiness.

Pathogenicity of entomopathogenic fungi on hibernating pupae of Cameraria ohridella Deschka & Dimic 1986 (Lepidoptera, Gracillariidae). Part 1: Pathogenicity against the naked pupa.

Strains from Paecilomyces fumosoroseus, Lecanicillium muscarium, Metarhizium anisopliae and Beauveria bassiana were examined in standardized Biotest to control the horse-chestnut leaf miner (Cameraria ohridella) in her pupal stage in winter. The fungi were pathogenic against the hibernating pupae of Cameraria ohridella at dose of 1.9 x 10(7) conidia/ml. They were aggressive, led to infection, death and mouldiness of naked pupae. Even at low temperature of 5 degrees C and 12 degrees C. L. muscarium strain V24 showed the highest pathogenicity after 4 weeks against this host, close followed by P. fumosoroseus strain P6. M. anisopliae strain 72 and 8. bassiana strain B412 were also pathogen but after a long-time period. Experiments gave information for general susceptibility of naked pupae of C. ohridella under low temperatures against entomopathogenic fungi. In further examinations it has to be tested, whether fungi can infected, when the pupae stay in their natural surroundings, the pupal cell in the leaf.

Spore adhesion of entomopathogenic fungi to larvae of Frankliniella occidentalis (Pergande, 1895)-(Thysanoptera: Thripidae).

The entomopathogenic fungus Verticillium lecanii proves to be very promising in controlling the population of Western Flower Thrips. Special investigations have been carried out to clear up the mechanisms of spore-adhesion at the insects with fluorescence-microscopy. After direct soil applications we have found a lot of spores/larva while applying low spore-concentrations. The loading with spores after indirect applications was very high as well. The addition of oils to the suspension enhanced the number of spores/insect and reduced the proportion of insects without spores.

Importance of sub optimal temperatures for the virulence of different geographical provenances of entomopathogenic fungus Verticillium lecanii (Zimm.) Viegas.

The virulence of the tested strains was developed from environmental conditions. The strain V24 had a stable virulence at all temperature levels and achieved in relation to the other examined strains the highest mortality of infected insects. The other strains have shown different changes of effectiveness at the sub optimal conditions. Germination of blastospores was temperature depending and correlated in the mostly cases with the virulence.