مجله دانش گیاه پزشکی ایران
سال پنجاه و سوم شماره 2 (پاییز و زمستان 1401)

 Myzus persicae (Sulzer) is one of the severe pests of Capsicum annuum L.Hippodamia variegata (Goeze), is an important predator in both the larval and adult stages. In this study, effect of foliar application of micronutrient fertilizers included iron, zinc, copper and manganese were investigated on the activity of antioxidant enzymes, amount of antioxidant non-enzymatic compounds and storage-macromolecules (protein, glycogen and triglyceride) of the third and fourth instar larvae of H. variegata fed on M. persicae. Results showed that the higher amount of protein, glycogen and triglyceride of the third and the fourth instar larvae of H. variegata were obtained on micronutrient fertilizers. The activity of antioxidant enzymes (catalase, superoxide dismutase, peroxidase, ascorbate-peroxidase and glucose-6-phosphate dehydrogenase) and the amount of non-enzymatic compounds (malondialdehyde and thiol) significantly decerased in the third and the fourth instar larvae of H. variegata on the micronutrient treatments compared to control. The increase of superoxide dismutase activity can indicate the occurrence of oxidative stress in the body of the third and the fourth instar larvae of predator H. variegata could be assigned to the accumulation of H2O2 in the body of M. persicae under the influence of the defensive secondary metabolites, which led to increase the activity of catalase and peroxidase. Thus, use of biological control agents along to use of micronutrients fertilizers in the integrated management programs of M. persicae could be effective by increasing of the amount of storage macromolecules and decreasing oxidative conditions, which can affect the vital processes of the predator.

Bitter apple (Citrullus colocynthis), camelthorn (Alhagi sp.), cordia (Cordia myxa), dill (Anethum graveolens), eucalyptus (Eucalyptus sp.), licorice (Glycyrrhiza glabra), plantain (Plantago sp.), and rosemary (Rosmarinus officinalis) are medicinal plants distributed in different parts of Khuzestan province. These plants could be host to many pathogenic and non-pathogenic fungi. In this study, 30 samples from medicinal plants showing leaf spot, stem canker and stem necrosis were collected during 2019-2020, and in which 23 isolates of six species in the family Didymellaceae were identified. Molphological characteristics were studied on potato – dextrose - agar (PDA). For molecular study, partial regions of tub2 gene were amplified using appropriate primers and sequenced. Based on molecular phylogeny in combination with morphology, the isolates were identified as follow: Allophoma labilis, Didymella glomerata, Epicoccum italicum, Neodidymelliopsis farokhinejad, Nothophoma raii and Xenodidymella glycyrrhizicola. In our knowledge, this is the first report of above species on surveyed hosts and first record of both E. italicum and N. raii for mycobiota of Iran.

Barley yellow dwarf disease is one of the most prevalent and economically important virus disease of cereals. Barley yellow dwarf virus, BYDV belongs to the family Luteoviridae is causal agent of barely yellow dwarf disease which can result up to 80% yield reduction in wheat. BYDV is present in most regions of Iran. For detection and study on distribution of BYDV, wheat and barley plants showing yellows and dwarfing symptoms were collected from fields of Malayer, Nahavand and Tuyserkan during growing season of 2020-2021. The samples were checked for BYDV infection using indirect-ELISA. The results showed presence of BYDV in most samples. Positive reactions to BYDV antibody in 80% of the Malayer samples, 90% of the Nahavand samples and 80% of the Tuyserkan samples were recorded. Also, total RNA extraction and RT-PCR were performed using specific BYDV-PAV primers; the most prevalent strain of BYDV in most regions of Iran. To verify the results, a sample with symptoms from Tuyserkan selected for sequencing. The BYDV isolate of Tuyserkan had 97% of homology with BYDV isolates were reported from Kahnouj, Karaj, Yazd and Arak, while it showed the least similarity with other Iranian isolates (about 85%).

The Safflower Carthamus with the scientific name tinctorius Carthamus L. belongs to the composite family and has antioxidant activity.Antifungal activity of silver nanoparticles synthesized by Safflower Carthamus extract was investigated against bean root rot disease caused by Fusarium solani in laboratory, greenhouse and field conditions.The synthesis of silver nanoparticles was evaluated by spectroscopic analysis (UV.Vis), Fourier transform infrared (FTIR), X-ray diffraction (XRD) and transmission electron microscopy (TEM).Factor disease severity were investigated in each pinto bean (Phaseolus vulgaris L.) plant.The results of the formation of silver nanoparticles were confirmed by changing the color of the silver nitrate solution to dark brown after adding the extract to the silver nitrate solution. The existence of the absorption maximum by UV-Vis analysis in the range of 415 nm is a proof of the synthesis of nanoparticles.Transmission electron microscopy showed the shape of nanoparticles to be spherical. XRD analysis showed the average size of nanoparticles to be 20 nanometers.In laboratory conditions, using the technique of mixing with the culture medium, the minimum growth inhibitory concentration (MIC) on the mycelial growth rate of the fungus was 200 ppm. PPM was evaluated by impregnating bean seeds with nanoparticles. The results of analysis of variance showed that the interaction effect between the concentration of different nanoparticles and the effect of the disease-causing fungus on the measured indicators is significant.

The lesser grain borer, Rhyzopertha dominica F. is an important pest of the stored products, which causes severe economic damage on grain. Regarding necesity of using alternative methods to chemical insecticides, in the present study the lethal and sublethal effects of the essential oils of Ajwain (Carum copticum L.) and fennel (Foeniculum vulgare Mill) along with diatomaceous earth were evaluated against R. dominica. The chemical compositions of the essential oils were determined by gas chromatography-mass spectrometry. The major components of Ajwain were phenol, benzene, and γ-terpinene and those of the fennel were propanal, trans-anethole, γ-terpinene, benzene, and cyclohexene. The toxicity of fennel essential oil (LC50 = 103.83 µl/l air) against the adults of R. dominica was higher than Ajwain essential oil (LC50 = 167.46 µl/l air). The LC50 for the diatomaceous earth was obtained 0.052 g/kg. Results of the experiment of sublethal effects (LC30) showed that males and females’ longevity and the fecundity of females were significantly lowest in the combination of Ajwain essential oil along with diatomaceous earth. Furthermore, the net reproductive rate (R0), intrinsic rate of natural increase (rm), and finite rate of increase (λ) of the pest, in both the combination of Ajwain essential oil along with diatomaceous earth and fennel essential oil along with diatomaceous earth were significantly lower (P < 0.05) than other treatments. The results of this study indicated that the essential oils of each of these plants in combination with diatomaceous earth can be used in the management programs of R. dominica.

Carob moth, Ectomyelois ceratoniae Zeller (Lep.: Pyralidae) is an economic pest, polyphagous, and globally distributed that attacks many crops throughout field and storage times. Developmental time of incubation period, larval period, pupal period, and overall immature stages of the carob moth were recorded in temperatures ranging from 10 to 35 °C under laboratory conditions. According to results outputs, temperature affected significantly developmental time of the carob moth at 1% significance level and increasing temperature lead to decreasing developmental time. Degree-Day and Ikemoto-Takai linear models were used to describe temperature-dependent development of the carob moth in this research. Although both of the linear models had shown an acceptable fitting to the experimental data, due to better statistical criteria, estimation of the Ikemoto-Takai linear model was considered as thermal indices of the pest. Estimated values for thermal requirement of incubation period, total larval period, pupal period and overall immature stages of the carob moth were 46.19, 577.73, 167.44 and 831.00 degree-days, respectively. Moreover, the values of the lower temperature threshold for the mentioned developmental stages were 11.29, 4.29, 4.55 and 4.83°C, respectively, using Ikemoto-Takai linear model.

Verticillium wilt is one of the important diseases that causes economic damage to pistachio trees. Arbuscular mycorrhizae in addition to improvement of plant growth, can increase tolerance to plant pathogens. In this research, the effect of mixture of three species of arbuscular mycorrhizal fungi, Funneliformis mosseae, Rhizophagus irregularis and Claroideoglomus etunicatum was evaluated on Verticillium wilt of pistachio rootstocks Ahmad Aghaei and Badami Zarand (susceptible and resistant to Verticillium dahliae, respectively). Arbuscular mycorrhizae (AM) inoculation was done at the time of sowing pistachio seeds and pathogen (Vd) inoculated after 52 days using amended inoculum on sand-barley flour-distilled water substrate. The experiment was performed as factorial in completely randomized design with 5 replications in greenhouse conditions. The results showed that the inoculation of AM increases shoot and root dry weight, stem height and diameter, leaf area, concentration of nutrients, proline, soluble sugars, chlorophyll comparison with the control and inoculated plants with the pathogen. In AM+Vd treatment, the presence of the pathogen only in Ahmad Aghaei rootstock caused a decrease in the colonization percentage of arbuscular mycorrhizal fungi comparison with the AM treatment. At the end of the experiment, the pathogenicity index in the Vd treatment was 3.9 and 1.9 in Ahmad Aghaei and Badami Zarand rootstocks respectively but in the AM+Vd treatment it reached to 3.6 and 1.1, which showed a significant decrease in disease severity. It is concluded that inoculation of AM by improving the growth, nutritional and biochemical characteristics can increase resistance of pistachio seedlings to Verticillium wilt.

Diapause is a physiological adaptation that allows an organism to survive adverse environmental conditions. Sunn pest, Eurygaster integriceps (Heteroptera: Scutelleridae), is a key pest of wheat and barley and univoltine species and its life cycle has two different phases, reproductive phase, and adult stage diapause. In this study, the gene expression patterns of Hexamerin storage protein were evaluated by quantitative Real-Time PCR assay in diapause and non-diapause female insects, in the Sunn pest’s fat body. The Hexamerin gene expression in diapausing females of sunn pest was 6.4 times higher than in non-diapausing females. The results of subcellular localization and signal peptide prediction suggested that the protein was categorized as an extracellular protein. According to phylogenetic analysis and multiple alignment analysis of the Sunn pest’s Hexamerin amino acid sequence and other bugs belonging to the Hemiptera order, the amino acid sequence was placed at clade belonging to the Hemiptera order (with 100 bootstrap number) and revealed high similarity and closeness to brown marmorated stink bug, Halyomorpha halys Hexamerin gene amino acid sequence (identity 62.6%). Identifying the Hexamerin gene as a reliable biochemical indicator for Sunn pest diapause can be a proper and valuable candidate for further studies at the cellular and molecular levels in this pest.

Common pistachio psylla, is a native pest in pistachio orchards of Iran. In this research, the LC50 and LC90 values of Movento, Sivanto, Starkel and Diabon pesticides were obtained on the nymphs of this pest in laboratory conditions. Then it was used against the pest in field conditions along with water spray treatment and potassium silicate liquid fertilizer. Finally, the mortality of nymphs was calculated 3, 7, 14 and 21 days after spraying. The field data were statistically analyzed as a factorial experiment based on a randomized complete block design in three replications with two factors of treatment and effect time. The values of LC50 and LC90 of insecticides in bioassay tests are respectively for Movento 500.78 and 1933.88, for Diabon 7259.57 and19839.41, for Sivanto 59.85 and 193.16 and for Starkel 7.19 and 36.96 µl/l were estimated. The results of the field test showed that the highest pest mortality on the third day after spraying were related to Diabon, Starkel, Sivanto insecticides, potassium silicate fertilizer, water spray and Movento pesticide, respectively equal to 81.33, 70.66., 57.33, 56.00, 48.00 and 45.66%. On the 14th day, the mortality rate in Movento treatment reached 84% and was significantly higher than other treatments. Therefore, the toxicity and durability of Diabon and Movento are more than other treatments. Based on the results of this research, Diabon pesticide, potassium silicate fertilizer and water spray due to its compatibility with the environment and Movento insecticide due to its durability It is suitable to control this pest.

Plants resistance against pests is one of the methods of replacing chemical pesticide that can keep the pest population below the economic injury level. Soil symbiotic bacteria can be useful factors in increasing the resistance of plants against herbivorous insects. The two treatments investigated in this research included the bean plant treated with bacteria and the bean plant without bacteria treatment as a control. The Vicia faba L. and black bean aphid were grown in a growth chamber at 25±4 0C, %50±5 RH and a photopriod of 14L: 10D hours. Then, 5 ml of bacterial suspension was added into the soil of sown mugs with a sterile syringe. These experiments on the effect of two treatments on faba bean showed that different treatments have a significant differences effect on the biological properties of black bean aphid. The highest developmental time (19.78±0.20 days) and the lowest fertility rate were occurred on P. polymyxa. There were significant differences between different treatments in terms of inherent rate of population increase (P≤0.5). The highest rate was occurred in control treatment (0.42±0.01 day-1) and the lowest in combination P. polymyxa (0.23±0.001 day-1). The life expectancy of black bean aphids, which was grown on P. polymyxa treated, was significantly lower than control. According to the results, it can be stated that faba bean plant treated can be effective in reducing the population of the aphids of the bean.

Crown and root rot is one of the important diseases of citrus trees in Iran. Various methods, including biological control, have been proposed to control this disease. Trichoderma species are widely present in all soils and plant materials. In this study, 27 Trichoderma strains were used for biological control of Phytophthora citrophthora. Measurement of cellulase enzyme and beta 1-3 glucanase produced by Trichoderma spp. was done using the dinitrosalicylic acid method. The results showed that the highest values are related to T. harzianum CT-763 and T. virens CT-9715 strains with 2 µmol/ml enzyme activity. Macroscopic and microscopic examinations of the dualculture of different Trichoderma strains with the pathogen, the inhibitory effect of volatile and non-volatile metabolites on mycelial growth of the pathogen were done. All Trichoderma strains and their volatile and non-volatile compounds inhibited on pathogen mycelia growth. The highest percentage of inhibition dualculture tests was caused by T. virens CT-9715. The highest inhibitory effect was determined for T. afroharzianum CT-891, T. aureoviridis CT-936, T. atroviride CT-865 with 100% and T. afroharzianum CT-55 with 50% in the non-volatile and volatile compounds assay, respectively. In microscopic examination of mycoparasitism effect of Trichoderma spp. and P. citrophthora, it was found that T. harzianum (CT-566, CT-862, CT-634, CT-873), T. afroharzianum CT-55 and T. aureoviridis CT-936, destroyed the mycelium of pathogen by a process such as twisting and lysis. For application of these successful local strains as biopesticide, it is necessary to perform additional studies on their biocontrol effects on Phytophthora in natural conditions.