Iranian Journal of Plant Protection Science
Year:2020 | Volume:51 | Issue:1|Papers Count:12

The carob moth Ectomyelois ceratoniae (Zeller) is a serious pest on carob, pomegranate, dates, citrus, and almond worldwide, and causes considerable losses in pomegranate orchards in Iran. Venturia canescens is one of the larval parasitoids of this pest that is known as the parasitoid of some stored products, too. The present study assessed the biological and demographic parameters of two populations of V. canescens (Hym.: Ichneumonidae) that were collected from pomegranate orchards, and stored products in storages. The each of two populations collected was developed on fifth instar larvae of Ephestia kuehniella as the host under laboratory conditions at 25 ± 1° C, 65 ± 5% RH, and a photoperiod of 16: 8 h (L: D). Life table data were analyzed using age-stage, two-sex life table theory. The developmental time of parasitoid wasps of orchards, and stored product populations were 22. 37 and 24. 73 days and the values of the oviposition period were 9. 33 and 8. 66 days, respectively. The life expectancy values were recorded 15. 07 and 18. 85 days, respectively. The intrinsic rate of increase (rm) were 0. 168 and 0. 153(day-1), the finite rates of increase (λ ) were 1. 183 and 1. 185 (day-1), the net reproductive rates (R0) were 78. 67 and 75. 93 (offspring/individual) and the mean generation times (T) were 25. 97 and 28. 23 days, respectively in above-mentioned populations. This study suggests that the orchard-originated population may have higher performance than the population of the stored product regarding the life table parameters. Complementary research to study biology and behavior of two populations needed.

Dubas bug Ommatissus lybicus de Bergevin, a sucking pest of the date palm, reduces the fruit's quality and marketability. The chemical application using tractor lance sprayers is the conventional control method against the pest in Iran. However, the foliage application utilized by high pressure increases the amount of drift, spray volume, and environmental contamination. Utilizing the Unmanned Aerial Vehicle (UAV) sprayer against the Dubas bug could reduce the mentioned disadvantages of the conventional sprayers. In this research, three different treatments were applied to control the pest using an RCBD statistical design in four replications at the Farashband area of Fars Province, Iran. Results showed the spray volume of tractor lance and UAV sprayers was 1100 and 28. 9 L ha-1, the run-off rate of the sprayers was 42. 6 and 11. 02%, respectively. The spraying coverage of the above sprayers was 2. 7 and 0. 8 ha per hour, respectively. There wasn't any significant difference between UAV and tractor lance sprayers in efficacy on 3 days after treatment but the effectiveness of UAV sprayer was significantly more than the tractor lance sprayer on 7 days after treatment. The spray quality coefficient in the UAV sprayer was 1. 35. The energy consumption of the tractor lance sprayer was 44. 4 times higher than that of the UAV sprayer. The spraying costs per hectare using the tractor lance sprayer were 1. 26 times of the UAV sprayer. Finally, in terms of technically and economically, the use of the UAV sprayer can be suitable in comparison with the tractor lance sprayer.

This research was conducted to identify endophytic bacteria over five years old citrus trees in the east of Guilan province. A total of 63 endophytic bacteria were isolated from symptomless leaves of Citrus aurantium, Citrus sinensis, Citrus sinensis var. thomson, Citrus unshiu, Citrus limon, Fortunella margarita, and Citrus medica. Isolates were grouped based on colony type and color. Then, morphological and biochemical characteristics of the six isolates were assessed as the candidate of different groups. According to molecular studies and phylogenetic analyses of the 16S rRNA region, these isolates were identified as Bacillus megaterium, Bacillus cereus, Arthrobacter agilis, Acinetobacter junii, and Pseudomonas azotoformans species. Among them, three species including A. agilis, A. junii, and P. azotoformans are reported as citrus endophytic bacteria from Iran and the world for the first time. Morphological, biochemical, molecular, and phylogenetical analyses are able to differentiate the genus and species of the endophyte isolates.

Fruits dropping, the lesser moth (Batrachedra amydraula Meyrick), spider mite (Oligonychus afrasiaticus McGregor), Date bunch fading, and Date palm inflorescence rot diseases (Mauginiella scaettae Cavara) are important injurious factors of the date palm. This research was carried out in the Abadan region from 2005 to 2014 to study the effects of temperature and humidity stresses on injury severity and simulation of date palm damages prediction model. Four different date palm orchards from four villages were selected and sampled monthly for the percentage of the date fruit damage until harvest. Climatic data were obtained from the Abadan meteorology station. Multivariate regression, thermal, and humidity models were used to design the system. Results showed that fruits dropping, the lesser moth, spider mite, Date bunch fading, and Khamedje diseases damages reached maximum at the months of April, June, July, September, and April, which coincided with the phenological stage of the Hababok, Kimri, Khark, turning Khark into Rotab, and Hababok, respectively. The damage of these factors started at temperature 21. 4, 21, 26. 7, 30. 2, and 21. 4 oC and relative humidity 14. 7, 20, 14. 7, 21. 3, and 27. 9 gradually increased to 40. 9, 36, 50, 50, and 37. 6 ° C, respectively. Forecasting model of damage factors has been significant at levels of 1, 5, 5, 5, and 5 percent, respectively. All of the forecasting models had a coefficient higher than 0. 7 and the detection error less than 25 percent. Among the meteorological indices, relative humidity and rainfall had the most influence on the variations in the severities of damages.

Faba Bean (Vicia faba) is an important legume among cultivated plants and the Alternaria leaf spot is a serious disease that causes broad damages and yield loss in Golestan and Mazandaran provinces. In the current research, sampling was carried out from Mazandaran and Golestan provinces. Morphological and molecular surveys of the obtained isolates showed that they belonged to A. alternata species. To evaluate the resistance of nine Faba Bean cultivars against the Alternaria leaf spot, area under disease progress curve (AUDPC) was calculated in the greenhouse condition. Also, the variation of some resistance related enzymes between resistant and susceptible lines was tested at different time intervals after inoculation. Statistical analysis showed a significant difference between cultivars (P≤ 0. 05). The Otono cultivar with the highest AUDPC and Zereshki cultivar with the least AUDPC were suggested as susceptible and resistant cultivars, respectively. The ANOVA of antioxidant enzymes showed positive effects on CAT, APX, and GPX levels after inoculation (P≤ 0. 01). Increasing the concentration of enzymes in incompatible interaction (Zereshki resistant cultivar) was greater than that of compatible interaction (Otono susceptible cultivar), indicates the role of these enzymes in activating plant defense responses in Faba Bean to interact with the pathogen and induce resistance. In general, the results showed that Zereshki cultivar with a low level of AUDPC and high expression of antioxidant enzymes has high potential to be used in breeding programs for resistance to Alternaria leaf spot.

Utilizing essential oils (EOs) as natural antifungal agents and alternatives for chemical fungicides has increased attention. In this study, chemical components and antifungal activity of Cinnamomum zeylanicum (CEO), Zataria multiflora (ZEO), and Satureja khuzestanica (SEO) plant essential oils (EOs) were identified to assess their effect in terms of concentration and exposure time on controlling Penicillium expansum. Also, modeling and optimizing antifungal properties of these EOs via response surface methodology (RSM). The main components of three EOs detected by GC-MS analysis were Cinnamaldehyde (80. 82%) for CEO, Thymol (32. 68%), Carvacrol (30. 57%), p-Cymene (8. 94), and γ-Terpinene (5. 96%) for ZEO and Carvacrol (38. 43%), γ-Terpinene (21. 89%), p-Cymene (16. 55%), and α-Terpinene (5. 76%) for SEO. Antifungal index (AI) in all EOs increased against the increment of concentration, but the effect of time was vice versa and over time, the AI decreased in all EOs. Moreover, based on the optimization results, it was determined that CEO and SEO had the highest and lowest inhibitory effects on growth of Penicillium expansum at the concentrations of 288. 633 and 590. 841 μ L. L-1 and time of 108. 607 and 238. 549 h, respectively, Furthermore, results of this study showed that the response surface method can be applied to modeling and optimizing the antifungal activity of these EOs as a suitable and accurate method.

Oak dieback is one of the most important diseases that presently affects the Zagros oak forests (Northwest to Southeast of Iran). The presence of Paecilomyces formosus, Biscogniauxia mediterranea, and Neoscytalidium novaehollandiae associated with oak trees that show dieback and declining symptoms in the forests of Kermanshah province and the molecular and pathogenic characteristics of these pathogenic isolates were investigated. In the molecular analysis using blast search tools, all three pathogens showed homology of 100% with the species mentioned in the GenBank. Pathogenicity tests revealed that all isolates of these three pathogens were capable of producing cankers on detached branches and inoculated seedlings of oak trees. Our results showed that all three species obtained from oak trees could produce cankers on excised branches of other trees. In comparison with pathogenicity on two-year-old seedlings under drought stress, there was a significant difference between the three species in terms of the rate of disease progression, so that B. mediterranea caused symptoms on seedlings inoculated under drought stress in a shorter time. Paecilomyces formosus caused symptoms in a longer period on the inoculated seedlings than the other two species. After inoculation, all cankers that extended upward and downward from the point of inoculation were evident on stems of all inoculated seedlings. Re-isolation was performed, and isolates were compared to original cultures providing evidence for fulfilling Koch’ s postulates. Investigation of the effect of temperature on the radial growth of pathogenic species showed that all three species are thermophilic fungi, which may be related to warming and drought.

Grape powdery mildew (GPM), caused by plant pathogenic fungus Erysiphe necator, is the most widespread disease of the grapevine worldwide, including Iran. Temporal analysis of disease epidemics was carried out by evaluating GPM in 30 vineyards in three cities of the Sistan region, including Zabol, Zahak, and Hamoon during 2017 and 2018. Field survey of vineyards to record disease incidence (I) and severity (S) was started from plant growth onset to harvest time, in a weekly program. Disease progress curves (DPCs) were evaluated by mathematical growth models including linear, monomolecular, logistic, log-logistic, and Gompertz, and their goodness of fit determined based on statistics such as the coefficient of determination (R2), adjusted R2 (aR2), and the standard error of estimates (SEE). Results showed that in total two years, for three variables of disease including disease incidence, leaf disease severity, and fruit disease severity, the monomolecular model was fitted with 100, 100, and 98. 33% of the studied epidemics, respectively. Means R2 of this model for three disease variables were calculated 91. 64%, 89. 60%, and 90. 27%, respectively, and this model was selected as the most appropriate for describing GPM progress in the Sistan region for the two studied years. Also, in a total of two years rates of increase (rm) per unit of disease in the vineyards for three disease variables were 0. 016, 0. 004, and 0. 005, respectively. This research is conducted for the first time in the region of Sistan and Iran.

Grapevine downy mildew caused by Plasmopara viticola is the most important factor in decreasing grape production in temperate and rainy regions. To investigate the disease progression curve in vineyards of North Khorasan province during two years of 2018 and 2019, scoring of the target vineyards was carried out each week on a regular schedule from mid-April at the bud swelling time from the vineyard. The incidence rate and severity of the disease in 80 vineyards from four counties of Bojnourd, Maneh and Samolghan, Shirvan, and Farouj were calculated. Linear regression was fitted to disease time progression curves with five population growth models as exponential, monomolecular, logistic, log-logistic, and gompertz models. The model fitness was determined based on statistics as coefficient of determination (R2), standard error of estimates (SEE) and adjusted coefficient of determination (Ra2). The results showed that exponential, monomolecular, logistic, log-logistic, and Gompertz models were fitted with 5, 27. 5, 12. 5, 17. 5, and 37. 5% of the disease in the studied gardens, respectively. Accordingly, Gompertz model with 96. 76% coefficient of determination was selected as the most suitable model to describe disease progression in North Khorasan province. Rates of increase (rG) per unit of disease in each vineyard was 0. 005 to 0. 048 (with an average of 0. 026). This is the first report of a study of the progression curve of grapevine downy mildew in Iran.

In this study, the fumigant toxicity of four essential oils, including eucalyptus leaf, eucalyptus flower, rosemary leaf, and mint leaf, was determined on the eggs (with less than 24 h) and the life span of the cowpea weevil (Callosobruchus maculatus). Results showed fumigant toxicity of these essential oils on the eggs in a dose-dependent manner showing the higher embryo mortality and the lesser hatching rate. Mint essential oil had the highest toxicity against the eggs with the 3. 3% of eggs hatchability. Mint essential oil also increased the larval duration from 23. 6 days in control to 27 days; however, the essential oils of eucalyptus leaf, eucalyptus flower, and rosemary showed no significant change in the larval duration as the survived embryos could complete larval stages in the equal time (statistically) with control. The use of herbal essential oils, especially mint essential oil, is very effective in controlling the cowpea weevil at the egg stage, and those may be a good substitute for common pesticides in warehouses.

In order to study the Bipolaris and Curvularia species associated with corn, sorghum and sugarcane, sampeling were performed from different regions of Iran (including Alborz, Ardabil, Fars, Gilan, Golestan, Khuzestan, Mazandaran and Zanjan provinces) during the summer of 2011 and 2012. Fungal species were identified based on morphological features and molecular data of ITS regions of ribosomal DNA. Eleven species including Viz. Bipolaris cynodontis (48 isolates), B. sorghicola (16 isolates), B. maydis (17 isolates), B. sorokiniana (seven isolates), B. bicolor (four isolates) and B. oryzae (two isolates), Curvularia spicifera (19 isolates), C. papendorfii (ten isolates), C. ellisii (two isolates), and C. hawaiiensis (one isolate) were identified. Pathogenicity test of the species were performed on four to six leaf stage of corn, sorghum and sugarcane seedlings. Finally, pathogenicity of B. maydis, B. sorokiniana and B. oryzae on corn and B. sorghicola on sorghum seedlings were confirmed. This is the first report of occurrence and pathogenicity of B. sorokiniana and B. oryzae on corn leaves in Iran.

Bean yellow mosaic virus, a species of the genus Potivirus, has a wide host range and a broad geographical distribution. BYMV causes high annual economic damage in various legumes such as faba beans in Iran. In this study, 13 BYMV isolates were collected from faba bean fields of different provinces of Iran (Sistan and Baluchestan, Hormozgan, Kerman, Khuzestan, Fars, Lorestan, Ilam, Hamadan, Ghazvin, Zanjan, Ardabil, East Azerbaijan). The coat protein (CP) region of the collected isolates was sequenced and then compared with the CP sequence of 178 isolates available in GenBank. The selected Iranian sequences showed 86-99% nucleotide sequence identities with other BYMV isolates. Phylogenetic relationships based on CP nucleotide sequences were estimated using the Maximum Likelihood method, after removing all recombinant sequences. Accordingly, all isolates excluding three isolates, AI38, PAC-1, BYMV-W were placed in eight monophyletic groups. Iranian isolates were located in two distinct groups, along with broadbean, lentil, bean, gladiolus and sunflower isolates from Japan, Australia, Iraq and Spain. According to the results there is no significant relation among clustering of BYMV isolates based on phylogenetic analysis of CP sequences and original host and country. The CP structure analysis of Iranian isolates and other selected isolates from GenBank revealed conservation of the C-terminus and the central region of the coat protein and the variation of the N-terminus.