No abstract

The laboratory bioassays showed the frozen stored Rhynchophorus polyhedrosis virus (FSRPV) and newly extracted one from died red palm weevil, Rhychophorus ferrugineus (oliv.) (RPW) collected from the field. The FSRPV was stored for 18 months under -4 o C. The newly extracted Rhynchophorus polyhedrosis virus (NERPV) was used for contamination of laboratory reared larvae of RPW at different ages in comparison of the pathogenicity between FSRPV and NERPV. The infected larvae were bioassayed and LC 50 and LT 50 values were determined. The range of LC 50 for NERPV was from 2.6x10 7 to 4.0x10 7 Polyhedra Inclusion Bodies (PIBs) /100 g diet, while the LC 50 for FSRPV ranged between 3.3 to 3.8x10 7 PIBs/100 g diet. The range of LT 50 for NERPV was from 2.4 to 24.3 days while it was from 3.2 to 25.9 days for FSRPS.

Laboratory and greenhouse experiments were conducted to investigate the efficacy of a biological control agent (Trichoderma harzianum) against the soil-borne plant pathogen (Fusarium oxysporum f. sp. lycopersici) as compared with a traditional fungicide (Vitavax ® -200). Results indicated that T. harzianum was more effective than Vitavax ® -200 for radial growth inhibition. Through seedling dip and soil application, Vitavax ® -200 was more effective than T. harzianum where it recorded the least wilt incidence comparing to untreated control, but it gave a shorter height of tomato plant than T. Harzianum with significant differences between them. Also, application of T. harzianum as antagonistic agent significantly increased the plant height and increased fruit yield/plant without significant differences with Vitavax ® when compared with untreated control.

The present study was performed during a periodical interval of nine months in (2014) at Alexandria Governorate, Egypt. Whereas, a laboratory trial was carried out to inspect the field collected dead adult land snails ofThebapisana (693 individuals). The inspection revealed that 19.0 % of these collected snails were infected with three pathogenic; bacteria; Bacillus theuringiensis (B.t.) (2.7%), B. cereus (0.1 %), and Brevibacterium sp. (10.1%) in addition to a polyhedrosis virus (2.7 %). Moreover, the made laboratory evaluation showed that the assessed daily cumulative mortality of snails as well as LC 50 (Concentration of active ingredient responsible for killing 50% of the examined number animals) value of B.t post 13 days of snail treatment was (7.3x10 8 Visible spore (VS)/ml), while these determined values for Brevibacteriumsp. and polyhedrosis virus(P.V) were (7.6 x 10 8 VSs/ml) and (3.3 x 10 6 Polyhedral Inclusion Bodies (P.I.Bs) /ml) after four and 16 days, respectively. The LT 50 (Time in days, needed to kill 50% of the exposed pest) for Brevibacterium sp. ranged from 9.8 to 16.3 days for the different tested concentrations. The LT 50 of lower concentration of polyhedrosis virus was much prolonged up to (10.6 days) compared to that of the highest concentration (1.5-day). Also, the LT 50 values of B.t ranged from 10.2 to 17.5 day for the lowest and highest tested concentrations .The ease and simplicity of the followed bioassay procedures, and the reliability of the method described, as shown by the statistical evaluation of the obtained data, justify the use of the adopted method in the present study.