Journal of Applied Research in Plant Protection
Year:2019 | Volume:7 | Issue:4 |Papers Count:7

Macrolophus pygmaeus Rambur is an most omnivorous predator which has considered in integrated pest management programs, especially for greenhouse pest management. In this study, biological properties and life table statistics of M. pygmaeus by feeding on Artemia urmiana Gunther cysts and Ephestia kuehniella Zeller eggs were studied under laboratory conditions (25± 1° C, 65± 5 % relative humidity and 16: 8h L: D photoperiod) with 60 replications. The pods of green bean Phaseoulus vulgaris L. served as oviposition substrate and the moisture source. Developmental time of nymphal stages which fed by of E. kuehniella eggs and Artemia cysts were 17. 04± 0. 11, 18. 06± 0. 18 d for males and 17. 31± 0. 09, 18. 17± 0. 15 d for females respectively and were significantly different as well as intrinsic rate of increase (rm) was 0. 080± 0. 005 and 0. 064± 0. 006 d– 1 respectively. Also, net reproductive rate (R0) was 18. 12± 2. 97 and 10. 70± 2. 43 eggs/individual on those food regims respectively. Furthermore, mean generation time (T) was estimated as 35. 93± 0. 33 and 36. 66± 0. 53 d respectively. Meanwhile, the reproductive parameters on flour moth larvae have been significantly higher than Artemia cyst. The results showed that feeding on E. kuehniella reduces nymphal period, while increases productivity and longevity of adults. According to the present findings, E. kuehniella is more suitable prey for rearing of this predator, but in absence of access to E. kuehniella, rearing on Artemia cysts is also possible.

Bacterial canker disease of stone fruit trees is one of the most important diseases in the world. In recent years, increasing of stone fruits canker disease symptoms as well as oozing and blast has been observed in some area in East Azerbaijan province of Iran. Fluorescent Pseudomonas syringae pv. syringae (Pss) strains were isolated from apricot trees which showed infected bud, bloom, branch and stem. The isolated strains were characterized based on their morphological, physiological and biochemical properties especially LOPAT and GATTa tests. Host preference was not observed among the tested strains and they showed pathogenicity on apricot green-cut twigs and green been pods with different disease severity. A 725-bp fragment of the syrB gene which is required for synthesis of syringomycin was amplified using specific primers in all strains. The tested strains inhibited the Geotrichum candidum mycelial growth with significant differences by toxin production. Using specific designed INAF/INAR primers, the inaZ gene was partially amplified and different range of ice nucleation activity was detected in all Pss strains. Constructing dendrograms using Bayesian inference showed genetic diversity among strains based on partial sequencing of 16S rRNA, rpoD and inaZ genes. These results showed that there are diversity among the causal agent strains of apricot canker disease based on both pathogenicity, toxin production and ice nucleation activity phenotypes and genetics.

Nucleopolyhedro virus (NPV) has an important role in pest management programs. Because of many advantages such as selective effect on larvae of insect pest, no undesirable effects on environment and non-target organisms and also compatibility with other pest management tactics. In this research, the virulence of a native isolate was evaluated on the larvae of cotton bollworm, Helicoverpa armigera Hü bner and diamond back moth, Plutella xylostella at 27± 2 oC, 65± 5% RH and 16L: 8D photoperiod. Based on the results, 50% lethal concentration (LC50) of virus on the 2nd larval instars of H. armigera and P. xylostella were determined as 9. 2×103 OB/ ml-1and 3. 8×104 OB/ml-1, respectively. Also results (LC50 – values), showed that NPV was more virulent on H. armigera than on the P. xylostella. Values obtained for 50% lethal time (LT50) of NPV were almost similar 5 and 4. 8 days post treatment for H. armigera and P. xylostella, respectively.

Leaf curl is a serious disease on peaches and nectarines. Planting of resistant varieties is one of the best ways to prevent and control this disease. In this research, 17 peach and nectarine cultivars were evaluated for susceptibility to the causative agent of peach leaf curl. The results of the evaluations in the first year indicated that, the highest disease severity was related to the Caldesi 2000 and July Alberta cultivars, based on the reaction type of cultivars, they were placed in the sensitive group (S). Then, Red Skin, Baby Gold, Springtime and Antonia cultivars had the highest disease severity and all of them were classified as semi-resistant (MR) cultivars. In contrast, Amesdan, Redhaven, Springcrest and Fayette respectively had the lowest severity of the disease, and all were highly resistant (HR). In the second year of evaluation, Springtime and Caldesi2000 cultivars had the highest rate of disease severity and according to the reaction type of cultivars, both of them classified, highly susceptible (HS). Then July Alberta and Baby Gold cultivars were susceptible to disease (S). In contrast, Amesdan, Redhaven and Robine cultivars had the lowest severity of disease and according to the type of cultivars reaction were classified highly resistant (HR). Therefore, according to the results of two years evaluation, it can be said that the cultivars Caldesi2000, Springcrest, then July Alberta and Baby Gold are the most susceptible and Amesdan and Redhaven are the highest resistance to the peach leaf curl disease.

Anagasta kuehniella Zeller (Lepidoptera: Pyralidae) causes the quality loss of the bread by feeding on flour. Disruption in insect’ s digestive enzymes through transgenic plants, expressing enzyme inhibitors, is a methods of pest control. So, the aim of the current study was to investigate the inhibitory effects of proteinaceous extracts of two varieties of wheat (Sivand, Sardari) and Triticale against activity of digestive α-amylase of fourth (L4) and fifth (L5) instars larvae of A. kuehniella. Ammonium sulfate (70%) was used to extract proteins from seeds. The optimal temperature and pH of α-amylase activity was found 40° C and 10, respectively. The results showed that the highest dose of proteinaceous extracts of Sivand and Sardari (13 μ g ml-1 protein) and Triticale (16 μ g ml-1 protein) reduced the enzyme activity, 73. 08%, 71. 07% and 65. 88% of L5 and 58. 16%, 42. 14% and 50. 25% of L4, respectively. The lowest dose of proteinaceous extracts of Sivand and Sardari (0. 812 μ g ml-1 protein) and Triticale (1 μ g ml-1 protein) inhibited the enzyme activity, 19. 93%, 17. 8% and 25. 26% of L5 and 11. 78%, 12. 81% and 10. 09% of L4, respectively. In the gel electrophoresis of enzyme without usage of inhibitors, one band was observed. At the highest dose of extracts, in the L5, amylase band disappeared and in the L4, waned band clearly. Band resolution was increased by reducing inhibitor dose. It was concluded that Sivand, Sardari and Triticale proteinaceous extracts can be used for management of A. kuehniella.

In this research, the effect of Trichoderma harzianum and T. atroviride against P. lingam was investigated in the laboratory and greenhouse conditions. Laboratory tests were followed as dual cultures and testing of the fungal volatile compounds. In the greenhouse, the antagonistic effects of the isolates were tested through treating rapeseed seeds and rapeseed above-ground parts with the spore suspension of the isolates in 106 spore per ml. The experiments were conducted in complete randomized design with four replications. Percent of plant mortality and disease severity were assessed. Both isolates showed antagonistic activities against the fungal phytopathogen. The two isolates T. harzianum and T. atroviride could inhibit the growth of the pathogen by 58. 6 and 71. 4 respectively in dual culture. In volatile compound phase, percent of growth inhibition were 15-21% and 31-39% in 120 and 240 hours after culture. In greenhouse experiments, antagonistic species could significantly (P<0. 01) reduce disease severity compared to control. The greenhouse results revealed that in the seed treatment experiment, Trichoderma isolates decreased the rapeseed blackleg to 42. 5 and 47. 5℅ , respectively after two weeks. Treating the above-ground parts with isolates T. harzianum and T. atroviride were significantly decreased the disease rate to 63. 13 and 78. 79℅ , respectively. So both Trichoderma species can biologically inhibit canola black leg, but T. atroviride was for the first time more effective than another one.

Root knot nematodes (Meloidogyne spp. ) are one of the most important plant parasitic nematodes that cause damage to most agricultural crops. In this study, the effect of the arbuscular mycorrhizal fungus (AMF) Funneliformis mosseae on root knot nematode M. incognita on two cucumber cultivars; tolerant and susceptible was investigated. This experiment was conducted in a completely randomized design with four treatments and four replications. The results showed that adding mycorrhizal fungus one month before inoculation of nematode caused a significant decrease in nematode pathogenicity factors (number of galls, number of eggs, eggs per egg mass and number of second stage juveniles) in both tolerant and susceptible cultivars (cv). Although the pathogenicity of the nematode in tolerant cultivars was lower than that of susceptible cvs, inoculation of susceptible roots with mycorrhizal fungus significantly reduced the pathogenicity of the nematode. The reproductive factor decreased in mycorrhizal plants in tolerant and susceptible cultivars in 50 and 66. 6%, respectively. The presence of mycorrhizal in tolerant and sensitive cultivar reduced 64 and 63. 3% of the second larval population in the soil, respectively. Also, the comparison of the mean number, size and area of giant cells and the number and diameter of the nucleus in 2 cvs showed a significant difference between the plants with or without mycorrhizal fungus. Since mycorrhizal fungus reduces the pathogenicity of the root knot nematode and increases the resistance of the cv susceptible to nematode, it can be considered as an option for biologic control of the root knot nematode.