مهندس فرشته صالحی

The efficiency of natural enemies as the key factor in the success of biological control programs, depends on different elements including the quality of their herbivore hosts. Similarly, it may be influenced by nutritional status and genetic differences of host plants in turn. This study was undertaken to determine the parasitism efficiency of Trichogramma principium (Sugonjaev & Sorokina) on the eggs of Helicoverpa armigera (Hübner) reared on different nitrogen fertilized tomato plant cultivars. All experiments were established in a growth chamber under 25 ± 1°C temperature, 60 ± 5% RH, 16:8 h. (L:D) conditions. Treatments included six tomato cultivars (Kingston, Riogrand, Earlyurbana, Redston, Superstrain-B and Primoearly) with four N levels (0, 2.1, 3.0, 3.9 g/ pot, Nitrogen as Urea 46%), in 5 replications. The value of the net parasitism rate (C0) of T. principium varied from 13.42±1.00 to 23.39± 2.59 hosts on the eggs of H. armigera reared on En0, and SBn+, respectively. The transformation rate from host population to parasitoid offspring (Qp) on all treatments was close to 1 (C0 ≅ R0). The finite parasitism rate (ω) which is used to determine the efficiency of a parasitoid, estimated as 0.1525 (min.) and 0.3164 (max.) hosts parasitoid-1 day-1 on the hosts reared on Earlyurbana and Superstrain-B, respectively. In general, T. principium had higher parasitism capacity on the hosts reared on Superstrain-B, Kingston and Riogrand with highest N levels, which were more suitable for parasitoid. This study showed that parasitism capacity of parasitoid was influenced by the host plant cultivar as well as positively correlated with the host plant nitrogen contenets.

Tourism is a general term in the holy Quran and includes some words like “Seyr”, “Safar”, “Siahaht”, “Nafr”, “Shoqah”, “Hijrah” and etc. This research attempts to clarify those terms that are related to tourism. The lexical and Quranic usage of the term tourism is studied first, and then the related words are evaluated in lexical, exegetical and Quranic domains. This approach, through finding the new teachings of the Quran, results in recognition of the fact that its teachings are systematic.

Aggregation response of the predatory bug Orius niger (Wolff) at different densities (5, 10, 20, 30, 40 and 50) of the second instar nymphs of Thrips tabaci Lind. was examined on a cucumber leaf disc as a patch. The number of predatory bugs and their allocated time per patch was recorded. The index (µ), in Hassell & May, at all densities of the predator (1, 2, 4, 8, 16 and 32) appeared greater than zero and, was indicative of its tendency to aggregate in the patches where a higher density of prey occurred. The percentage time spent by the predatory bug at different patch densities of T. tabaci showed that it allocated more time in patches with higher densities of prey.