نشریه کنترل بیولوژیک آفات و بیماری های گیاهی
سال دوم شماره 1 (بهار و تابستان 1392)

Root rot disease of broad-bean caused by Fusarium solani is a serious disease of this crop. Due to high cost and difficulty of the disease control, interaction between root nodulating bacteria and Fusarium. solani were evaluated to use for disease management. Broad-bean root nodulating bacteria were isolated and their interaction with F. solani was investigated in culture medium in a completely randomized design with 58 treatments and three replicates. Results showed significant differences among the strains which Rhizobium leguminosarum NSZ3 with 1.93 mm and strain R. leguminosarum NSZ22 with 0.75 mm inhibition zone were the most and less effective respectively. Efficacy of representative strains against root rot disease and some growth factors of broad-bean under green-house condition were investigated in a randomized complete block design with three replicates. Plant growth characteristics including plant dry weight, root length and root dry weight were recorded after 30 days. Results indicated significant differences among the strains which NSZ3 increased plant dry weight by 61% in comparison to control.
Strains NSZ3 and NSZ64 showed the highest effectiveness on root dry weight and increased root weight significantly compared to the control. Strain NSZ3 increased root length by 53% in comparison to the control. Seed dressing by bacterial suspension found to be more effective than soil drench for controlling F. solani. Strategy for selection and application of root-nodulating bacteria with inhibitory against soil-borne pathogens, may promote soil microbial balance, increase the yield, reduce the disease control cost and protect the biological resources and the agricultural environment.

To evaluate the effect of Glomus mosseae and Trichoderma virens, on root knot nematode (Meloidogyne spp.) in tomato plants, a greenhouse experiment was performed in a completely randomized design with seven treatments in four replicates. T. virens was isolated from the wheat fields of Fars province and cultured on PDA medium. G. mosseae provided from the Department of Horticulture, University of Valiasr, Rafsanjan. Pure culture of G. mosseae, was established in pot culture. The individual and mixed effect of both fungi was assessed. The results indicated the positive effect of the mixture of the both fungi (T. virens G. mosseae) on tomato growth as well as the nematode reproduction factors. In this treatment, the number of galls/g of root, compare to 7.28 in control reduced to 0.72, the number of egg masses reduced from 2.76 to 0.39, number of J2s from 3553.5 to 2471.25 and reproduction factor reduced from 2.13 to 1.48. The growth-related factors in tomato plants were improved in treatments G. mosseae and T. virens G. mosseae, as compare to both inoculated with M. javanica and uninoculated controls.

In this research, Bacillus strains efficiency were tested to control root knot nematode, Meloidogyne javanica .One hundred and fifty strains were isolated from tomato rhizosphere. Antagonistic activity of strains on M. javanica was checked in vitro assay. Nematicidal ability of bacterial suspension of 1 × 108 cfu/ml was investigated on nematode egg and larvae with three replication using Random Complete Design. Eight strains which were successful in egg hatch prohibition, larvae mortality and also were positive in enzymatic function were selected for greenhouse experiments. Based on morphological, physiological and biochemical methods, representative isolates are belonged to Bacillus cereus (Bag2.13, N2.2 Md1.8 and Chl.2), B. licheniformis (Ma1.3 and MA1.7) and Bacillus sp. (Bag2.13, MD1.8 and MD6.5). In greenhouse tests, the most effective strains were MD6.5 and Bag2.13 that can control the disease considerably. The results indicated acceptable correlation (-0.524) among bacterial suspension, egg hatch prohibition percentage in lab and gall index in greenhouse. This is the first report of application native Bacillus strains, on tomato root knot nematode control in greenhouse condition.

Tomato Fusarium wilt, caused by Fusarium oxysporum f. sp. lycopersici (FOL), is one of the most important diseases of tomato in Iran and in the whole world. Recently, in order to reduce hazardous effects of chemical pesticides, these days, attempts have been made to use safer methods for controlling plant pathogens. Therefore, using antifungal plant materials has been highly regarded during past several decades. In the current study, essential oils of ten medicinal plants were obtained by hydro- distillation method. Antifungal effects of 50, 100 and 200 µl of essential oils were studied on mycelia growth of (FOL) using a paper disc method on agar medium. Treated samples were kept at 26 ºC and colony diameter was measured and analyzed after 7 days. Experimental treatments (50, 100 and 200 µl of ten essential oils) were arranged in a completely randomized design with three replications. The results of in vitro trials indicated that different concentrations had no significant effects on fungus growth; however, the essential oils of Savory and Eucalyptus showed the strongest inhibitory effects (89.5% and 30.7%, respectively) and the essential oils of Common rue and Felty germander showed the less antifungal activity against FOL in comparison to N-hexane control (p≤0.05). However, Essential oil of Savory had the most inhibitory effects in all three concentrations.

In order to assay the pathogenicity of the entomopathogenic nematode, Heterorhabditis bacteriophora Poinar, 1975 on the indigenous population of common earwig, Forficula auricularia L., several concentrations including 100, 250, 500, 1000, 1500, 2000 and 3000 (IJs/ml of DW) were used in the laboratory conditions. In this experiment, effects of time (F 1, 91= 4.22, P

In this research, the effect of entomopathogenic fungus, Beauveria bassiana (Ascomycota, Hypocreales), on functional response (in laboratory) and reproduction (in microcosm) of parasitoid wasp, Aphidius matricariae Haliday (Hym.: Braconidae) on its host, Myzus persicae (Sulzer) (Hem.: Aphididae) was investigated. Illustrating number of mummified aphids versus initial density of green peach aphid showed type III functional response. The results declared the parasitoid wasp had maximum efficiency to parasite green peach aphid when both wasp and aphid were not exposed to the entomopathogenic fungus. In this case, values of b and Th were 0.1053 and 0.0179, respectively. The previous infection of green peach aphid significantly affected the number of produced mummies and fungus-sporulating cadavers after 16 days. The mean numbers of produced mummies for control, parasitized aphids in 24 and 72 h intervals after fungal infection were 14.33±2.86, 10.66±2.13 and 6.66±1.33, respectively and indicated that relative timing for parasitism and fungal infection was determinant in ultimate result of the competition.

Learning host or prey-related olfactory cues may lead to increase efficiency and foraging capacity of biocontrol agents such as Trichogramma egg parasitoid wasps in nature. The egg parasitoids, Trichogramma species (Hym., Chalcidoidea, Trichogrammatidae), are most commonly and important biocontrol agents that have successfully been utilized against several lepidopteran pests, especially through inundative releases. Worldwide, over 32 million hectares of agriculture and forestry have been treated annually with Trichogramma for controlling various insect pests. Wolbachia is endosymbiotic bacterium induces parthenogenesis in Trichogramma wasps and producing female offspring. This research was conducted to study learning ability of Wolbachia infected T. brassicae to Lemon and Peppermint odors by wind tunnel under controlled conditions. According to obtained results, wasps showed significant difference in responses to conditioned and unconditioned odors. Memory duration of conditioned wasps lasted till 12 hours after conditioning. Odor learning ability recognition of biocontrol agents such as T.brassicae may result in increment of their efficiency in applied biological control programs.

Functional response, as describing the rates of predation in different prey density, and determining the predator efficiency, is important in the regulation of prey populations. The functional response of male and female adult of lady beetle, Hippodamia variegata, was studied at different densities of green peach aphid under laboratory conditions on canola Brassica napus L. (cv. RGS003). Nymphs were used to enhance the accuracy of contemporaries. The experiment was carried out on leaf disk of canola in Petri dish in 15-20 replicates. After 24 hours number of killed prey was recorded. The results showed that male and female of Hippodamia variegata revealed a type II functional response to different density of 2, 4, 8, 16, 32, 64, 80, 128 for female, and 2, 4, 8, 16, 32, 45, 70 for male. The rate of searching efficiency and handling time were assessed as 0.167 h-1 and 0.333 h for male, 0.135 h-1 and 0.193 h for female, respectively. By using an equation with indicator variable, functional responses of adult males and females were compared, it showed that searching efficiency had no significant differences, but comparisons of handling times showed significant differences. Thus it can be concluded that the ability of female predators is greater than the male to control the green peach aphid.