Applied Entomology and Phytopathology
Year:2019 | Volume:86 | Issue:2 (107)|Papers Count:10

Using natural plant products has become more important as viable alternatives to control postharvest diseases. The effect of four essential oils of medicine plants including Thymus vulgaris, Cuminum cyminum, Allium sativum and Aloe vera were tested (100, 200, 300, 400ppm) in vitro and in vivo (200, 300, 400 ppm) for their fungal inhibitory percentage and antagonistic properties against Penicillium digitatum. Plant essential oil extracted by hydro distillation using a Clevenger-type, and minimal inhibition concentrations (MIC) was determined using agar dilution method. In vitro inhibitory effects of the plant extracts showed maximum percent inhibition (99. 95%) by thyme extract, which also had the best MIC value against P. digitatum. GC-MS analysis of the thyme oils extract led to the identification of 22 different components which carvacrol (2. 88%), 60. 18% thymol (60. 18%), linalool (4. 22%),
-terpinene (6. 39%) were found to be the main constituents in T. vulgaris. Thyme essential oil inoculated into wounds with the pathogen stimulated the orange to increase production of phenol compound, catalase and peroxidase activity. Thus, different concentrations of the thyme essential oil are effective on controlling the producing agent of the green mold fungus significantly, and induce resistance to orange by effect on defense enzyme.

The pistachio twig borer moth, Kermania pistaciella Amsel (Lep.: Tineidae) is one of the most important pests of pistachio trees in Iran. This study was carried out with the purpose of examining the infestation rate for various cultivars to this pest. The field studies were conducted for the collection of existing pistachio cultivars at three pistachio research stations including Rafsanjan stations 1 and 2 as well as at Kerman station respectively on 38, 25 and 29 pistachio cultivars during 2005 – 2008. The infestation rate was determined with selection of six trees related to each pistachio cultivar, and 50 clusters of each tentative tree were picked up randomly, and also by sampling from the healthy and infected clusters simultaneously at harvesting time in September. The results showed that, the cultivars of Italiaei Rize were the most infested and Lak Sirizei had the least infected clusters of this pest at the station number 1. In station number 2, the cultivars of Shasti and Khanjari Damghan indicated the highest and the least infested clusters of this pest respectively, but the infestation rate for 4 commercial cultivars e. g. Ohadi, Ahmad Aghaei, Kallehghochi and Akbari, had no significant difference. In Kerman station, the highest infestation obtained for cultivar of Karim-Abadi and cultivar of Harati had the least infested clusters. Maximum emergence of matured K. pistaciella occurred since pollination stage until the time of fruit formation on commercial pistachio cultivars. The information obtained from this research can be used for controlling management of this pest.

Tobacco streak virus is one of the most important destructive viruse of crops, and reported as a causal agent of soybean bud blight in different region of world. In this study, the response of soybean cultivars, that were common in the north of Iran, was evaluated to TSV and the possible effect of virus on soybean, under greenhouse conditions. This research was carried out in two way factorial arrangement on a CRD (completely randomized design) with virus isolates (soybean, mungbean and sunflower isolates) and soybean cultivars (Williams, Amir, Katol, Saman, Sari) as treatments in 3 replications. Plants were tested for TSV infection by DAS-ELISA method with specific polyclonal antibody, and polymerase chain reaction (PCR) with specific designed primer. Results showed that viral isolates significantly reduced the plant length, number of nodes, and number of healthy pods. Cultivars had significant effect on growth indices: plant length, number of nodes, number of pod and fresh weight, too. The lowest differences in growth indices and podding in compare of control group observed in Williams cultivar whereas the highest seen in Amir and Katol cultivars. The symptoms caused by soybean isolate were more severe than mungbean and sunflower isolates. Results indicated significant effect of viral isolates and soybean cultivars on podding.

The symptoms of bacterial leaf spot and blight on onion (Allium cepa L. ) plants were observed in Fars (Eghlid) and Kermanshah (Bistoun) provinces with the rate of occurrence varying from 90 to 100% of the plants. In order to isolation and identification of the causal agent, suspicious samples were collected from infected fields. By culturing the samples on nutrient agar medium, 30 bacterial isolates were obtained. Pathogenicity test of the isolates on Allium spp. was performed and their pathogenicity was proved on onion, spring onion and leek. The isolates showed an identical total cell soluble protein pattern in SDS-PAGE. The isolates were similar to Pseudomonas syringae pv. porri based on phenotypic characteristics such as production of fluorescent pigment in KB medium, LOPAT tests, and utilization of different carbon sources. Genomic profiles generated with BOX-PCR placed the isolates into one groups. The results of the amplification and sequencing of the 16S rRNA, gyrB, and rpoD genes showed that the isolates belong to P. syringae pv. porri. This is the first report of the presence of the P. syringae pv. porri in Kermanshah province. Management of the disease seems to be necessary to prevent the disease epidemy.

Potato leaf roll disease is one of the most important and widely distributed viral diseases of potato. Like other plant viruses, the use of resistant cultivars is the most effective control measure of this disease. In this study, the reactions of some potato cultivars and genotypes to Potato leafroll virus (PLRV) were evaluated in a field trial experiment. The experiment conducted as a randomized complete block design with 12 treatments and three replications. Each plot of the experimental design included a planting row of five potato plants of each cultivar/genotype. The experimental plants were then inoculated with the virus by putting 10 PLRV-carrying green peach aphids on each plant. One month after inoculation, the plants were examined for PLRV infection by observing symptoms development and using enzymelinked immunosorbent assay (ELISA) test. The results revealed significant differences between the PLRV-infection rates of the potato cultivars/genotypes tested. The potato genotype 803970/13 with having no infected plant was evaluated as highly resistant to PLRV. The cultivar “ Sante” was resistant, the cultivar “ Lady Rosetta” and the genotype “ 397015/31” were moderately resistant, cultivar “ Diamant” was moderately susceptible and the rest of genotypes or cultivars were found susceptible or highly susceptible. The results also showed a significant correlation (79%) between the infection rates of the test plants based on symptom development and those of the ELISA tests.

Sclerotinia stem rot is a rapeseed important disease in the world and Iran. For measuring disease incidence and severity and determination relationship between them, 240 rapeseed fields were investigated in Mazandaran province during years 2010, 2011, 2015 and 2016, and their disease amounts recorded in weekly surveys. Based on final incidence and severity, there were significant differences (P<0. 01) between regions and years. The highest incidence and severity (34. 02 and 23. 70 percent) was in year 2016 and the lowest of them (12. 85 and 6. 32 percent) in year 2015. Between regions, Galogah and Sari had the highest and lowest disease infection respectively. In order to determine relationship between two mentioned quantities, the related data, were fitted with different mathematical models by linear regression analysis method. Based on statistical analyses such as coefficient of determination (R2) and standard error of estimates, linear allometric and square root models had good fitness with data. The linear model was selected as the final model because of the simplicity and having low computational complexity. Based on slope of linear model equation, there was significant difference (P<0. 01) between four years of investigation. The equation of the model for years 2010 and 2016 was S=0. 72(I)-0. 99 and for years 2011 and 2015 was S=0. 55(I)– 0. 61. Weather conditions had significant effects on disease infection in different years.

In this research, examination of the disease distribution, the physiological relationship between disease agents and its sites and evaluation of cultivars resistance were investigated. The disease agent identified as Zymoseptoria tritici. Distribution map prepared by ArcGIS v. 10. 2 software. The isolates growth tested in different temperature and its relation to their region climatic conditions evaluated. 26 cultivars evaluated in the greenhouse, evaluated. As a result, isolate growth average had correlation with region climatic conditions. In terms of growth, the Nokandeh isolate was the most and the Ramian isolate was lowest. The highest isolates growth was at 15° C and the lowest growth rates were at 10° C. The disease was detected in 8 counties. Ramian and Kurdkoy were identified as the disease contaminated sites. Among the examined cultivars, 4 cultivars such as Falat, Mehrgan, Ghabos, and Roshan were resistant, 14 cultivars such as Shirodi, Morvarid, Moghan, Koohdasht, Gaspar, Aftab, Shahryar, Gonbad, Alamoot, Aflak, Zarin, Karaj-1, Tous, and Azar-2 were moderately resistant and 7 cultivars such as Karim, Dez, Khazar-1, Star, Hamoon, Ofogh, Eram and Tajan were evaluated as susceptible. Rumian isolate had the highest disease severity. Due to the wide distribution of STB, the existence of favorable conditions and identification of disease region center, it is possible to monitor the appearance of infection at February and March and make a broadcast of the disease prevalence. Also, by evaluating of wheat genotypes, introducing and planting the resistant cultivars, it could reduce the disease in the future.

The response of a natural enemy to its host’ densities has been defined as “ functional response” . It has been considered a feasible technique to measure the efficacy of biocontrol agents. We employed the concept to evaluate the functional response of adult female and male of Nesidiocoris tenuis under laboratory conditions by feeding on different densities (1, 2, 4, 8, 16, 32, 64, and 96) of Ephestia kuehniella and Tuta absoluta eggs in 7 replicates. The predators were kept unfed for 24 hours. Then the number of eaten prey was recorded after 24 hours. The results showed type III functional response for all tests based on logistic regression. The attack constants (b) of females and males fed on E. kuehniella and T. absoluta eggs were 0. 0061 ± 0. 0018, 0. 0048 ± 0. 0009, and 0. 0093 ± 0. 0037, 0. 0042 ± 0. 001, respectively. The estimated handling times (Th) for females and males on the respective preys were 0. 3598 ± 0. 0193, 0. 2905 ± 0. 0136, and 0. 9032 ± 0. 0511 and 0. 5859 ± 0. 0303 h. In conclusion, N. tenuis females had shorter handling time, greater attack rate and maximum daily consumption (73. 86 eggs) compared with those of males. Therefore, results strongly support that female predators could be more effective in controlling T. absoluta.

Common bean root rot which is an economically important fungal diseases worldwide. Distribution and relative dominance of the disease was investigated in the farms of the major bean cultivating regions and clima of Lorestan province. The dominant pathogenic fungi were identified based on colony morphology and microscopic characteristics, and then confirmed by molecular technique using
-tubulin and TEF1-
genes. Frequency of fungal isolate and the pathogenicity tests showed that F. solani, with 33. 42 % isolation frequency was the most important causal agent of common bean root and crown rot in Lorestan province followed by F. oxysporum, Macrophomina phaseolina and Rhizoctonia solani with 26. 55, 15. 55 and 7. 73 %, respectively. Frequencies of root rot pathogens distributed across bean farms of Selseleh, Borujerd, Azna, , Doroud and Aligudarz were 24. 57, 18. 64, 16. 58, 15. 20 and 8. 25 %. respectively. The frequency of the pathogen isolated from common bean plants at the early growth, flowering and podding stages was 20. 70, 26. 37 and 52. 92 %, respectively. Based on the climate zone parameter, the highest frequency of fungal agents was belonged to semi-humid temperate climate.

Collembola are the most abundant soil living arthropods found almost everywhere. These small hexapods have remained unknown in many parts of Iran including Lorestan province. In order to study of collembola fauna of this province, soil samples were collected from Khoram-Abad in 2012. The springtails were extracted from collected soil samples by Berlese funnel and were identified after mounting on slides. Seven species belonging to five genera and three families were identified as follows: Family Isotomidae; Isotomodella alticola (Bagnall, 1949); Folsomides parvulus Stach, 1922; Family Tullbergiidae; Metaphorura denisi Simó n Benito, 1985; Family Onychiuridae; Protaphorura gisini (Haybach, 1960); P. fimata (Gisin, 1952); Thalassaphorura zschokkei (Handschin, 1919) and T. encarpata (Denis, 1931). The genus Isotomodella Martynova, 1968 and four species, I. alticola, M. denisi, P. gisini and T. zschokkei, are newly reported from Iran. Furthermore, all species are new records for Lorestan province.