Objective: Marine fungi play an important role in human and animal health, leading compounds to new drug discoveries and prospects for their bioactivity potential. Materials and Methods: Paecilomyces WE3-F was isolated from marine sediment (Red Sea, Shalateen, Egypt). Fungal isolate was screened for their antagonistic activity against four Gram-positive (Bacillus cereus, Lesteria monocytogenes, Micrococcus luteus and Staphylococcu aureus) and four Gram-negative (Aeromonas hydrophila, Flavobacteruim sp, Pseudomonas aeruginosa and Vibrio cholera,) pathogenic bacteria. Paecilomyces WE3-F was identified using 18S rRNA technology. Seven factors were chosen to be screened for bioactivity using the Placket Burman experimental design: sucrose, yeast extract, Na NO3, temperature, initial pH, inoculum size, and incubation period. Results: Among conditional factors, acidic pH and 1.5 ml inoculum size favored the bioactive metabolites. Furthermore, a number of solvents have been experimented for the extraction of the bioactive metabolite(s). Dichloromethane (DCM) crude extract from the fermentation broth of a marine Paecilomyces WE3-F showed the highest activity with averages of 26 and 24 mm against G-ve and G+ve, respectively. Under optimal culture conditions, the maximum extractable compound concentration in a 10-L culture medium reached 83.4 mg/L. Based on data obtained by thin layer chromatogram (TLC), gas chromatography -mass spectrum (GC-MS) and Fourier Transform Infrared (FTIR) the major compound, betulin was structurally identified. Conclusions:The isolated marine Paecilomyces WE3-F, therefore, showed the ability to produce a betulin yield after optimal operating conditions for antibacterial potential.

The kairomonal effect of hexane extract of the larvae of Ostrinia nubilalis and Sesamia cretica on Bracon breuicornis adults was evaluated through olfactometer tests. The parasitoid males showed no definite response to any kairomone. Females were attracted to the kairomone of S. cretica more than to that of 0. nubilalis. Highly significant effect of the sex pheromone of 0. nubilalis on the females of B. breuicornis was recorded. Kairomones (hexane extracts of larvae) varied in their effect on the released B. brevicornis parasitoids. The kairomone of S. cretica increased the parasitisation from 7.74 to 17.05%, while the kairomones of 0. nubilalis and of Spodoptera littoralis were not significantly effective. Spraying molasses solution (10%) on the corn stalks before releasing B. brevicornis parasitoids increased the rate of parasitism from 7.74 to 28.21%. The concentration of 5% gave insignificant increase in the parasitisation rate.

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Twenty components of the essential oil encountered in the oil glands of 3 citrus species with different degrees of susceptibility to infestation with the red scale Aonidiella aurantii Maskel. have been identified through GLC. Citrus species with higher hydrocarbons content are more susceptible, while those with higher alcoholic terpenes content are more resistant to insect infestation. The behavioural response of the crawlers of this scale insect to the individual components of the essential oil support to a great extent this view, where the crawlers were attracted to the hydrocarbons and but they avoided or showed no obvious response to the acoholic terpenes. The correlation between this insect species and citrus trees has been discussed. Zusammenfassung Komponenten des Öls von drei Citrus‐Arten in Beziehung zum Schildlausbefall Es wurden 20 Komponenten des von den Öldrüsen dreier Citrus‐Arten produzierten Öls mit unterschiedlicher Wirkung auf den Befall durch die Rote Schildlaus, Aonidiella aurantii Mask. identifiziert. Citrus‐Arten mit höherem Hydrocarbon‐Gehalt zeigten sich empfindlicher, solche mit höherem Gehalt an alkoholischen Terpenen dagegen resistenter gegen den Schildlausbefall. Das Verhalten der Schildlauslarven gegenüber den einzelen Komponenten des Öls wies in dieselbe Richtung: die Larven wurden von den Hydrocarbonen, nicht jedoch von den alkoholischen Terpenen angezogen. Die Beziehungen zwischen der Schildlaus und den Citrus‐Bäumen werden erörtert.

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