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Culture filtrates (CF) of two species of the nematophagous fungi, Arthrobotrys oligospora and Arthrobotrys conoidesat three concentrations (25%, 50% and 100%) of stock, were tested on the mortality of second stage juveniles (J2) and egg hatching rate of Meloidogyne incognita and Meloidogyne javanica. Results showed that the percent juvenile mortality was directly proportional to concentration of the filtrates. Egg hatching rate of these nematodes was inversely affected by increasing concentrations. Also CFs had various impacts on the mortality of J2 and egg hatching rate. In case of M. incognita maximum J2 mortality (28.98%) occurred after 24 hours of exposure to A. conoides filtrate at concentration of 100%. The minimum toxicity (12.5% J2 mortality) was recorded for A. oligospora at 25% filtrate concentration. At the same time, the highest rate of J2 mortality of M. javanica (19.18%) belonged to the 100% concentration of A. conoides, while minimum toxicity belonged to 25% concentration of A. oligospora causing 9.09% mortality. Maximum egg hatching rate for M. incognita (30.75%) belonged to control and minimum hatching rate (1.25%) belonged to 100% concentration of A. conoides. The highest hatching rate of M. javanica (36.25%)belonged to control and minimum hatching rate (1.25%) occurred at 100% concentration of A. conoides.

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Plant quality in herbivores’ diet may affect the performance of both herbivore and its parasitoids. In the present research, parasitism capacity of Diadegma semiclausum (Hellen) on Plutella xylostella (L.) reared on different genetically manipulated Brassica plants including the canola’s progenitor (Brassica rapa L.), two cultivated canola cultivars (Cultivar-Opera and Cultivar-RGS₀₀₃), one hybrid (Hybrid-Hyula₄₀₁), one gamma mutated (Mutant-RGS₀₀₃), and one transgenic (Transgenic-PF) genotype was determined. All experiments were carried out in a growth chamber at 25±1˚C, 65±5% RH, and a photoperiod of 16:8 (L: D) hour. The value of the net parasitism rate (C₀) of D. semiclausum was 14.94, 20.12, 14.95, 12.20, 13.94, and 12.55 hosts on B. rapa, Cultivar-Opera, Cultivar-RGS₀₀₃, Hybrid-Hyula₄₀₁, Mutant-RGS₀₀₃, and Transgenic-PF, respectively. The transformation rate from host population to parasitoid offspring (Q_p) on all genotypes was close to 1 (C₀ R₀). Moreover, the value of the finite parasitism rate  was 0.271, 0.285, 0.277, 0.202, 0.205, and 0.202 host parasitoid^-1 day^-1 on the above-mentioned genotypes, respectively. The finite parasitism rate considers the finite rate of increase, the stable age-stage distribution, and the age-stage specific parasitism rate; therefore, this parameter could be used to assess the efficiency of a parasitoid. In conclusion, D. semiclausum had higher parasitism capacity on canola’s progenitor and the cultivated genotypes which were more suitable for parasitoid’s host based on secondary metabolites concentration.