نشریه پژوهش های کاربردی در گیاه پزشکی
سال دوازدهم شماره 3 (پاییز 1402)

Mountains of Shahiyoon and Salandkooh (Dezful, Khuzestan), Kabirkooh (Abdanan, Ilam) and ZazoMahroo (Aligoodarz, Lorestan) constitute small parts of the Zagrosian forests in Iran. During 2020-2022, 50 symptomatic samples from forest trees including Acer sp., Amygdalus scoparia, Crataegus sp., Pistacia atlantica, Quercus brantii and Ziziphus sp., showing leaf blight, leaf spot, fruit rot, decline and dieback, were collected. Totally, 153 fungal isolates were obtained on potato–dextrose–agar medium (PDA), of which 17 were identified at species level based on combination of morphological characteristics and sequence data of marker genes. Morphological characteristics and growth rate were evaluated on oat -meal - agar (OA) and PDA. The ITS-rDNA region (in some isolates) and part of the tub2 (in all isolates) and rpb2 (in some isolates) genes were amplified and sequenced. The obtained sequences were compared using BLASTn search algorithm in NCBI database and their phylogenetic analyses were performed based on single or multiple genomic regions. Accordingly, the isolates were identified as follow: Chaetomium anastomosans, C. ascotrichoides, C. subglobosum, Didymella pomorum, D. prolaticolla, and Paramicrosphaeropsis iranica. Based on literature, this is the first record of C. anastomosans, C. subglobosum and D. prolaticolla for the mycobiota of Iran. In addition, new hosts for C. anastomosans (P. atlantica, Q. brantii and Crataegus sp.), C. ascotrichoides (Acer sp.), C. subglobosum (Q. brantii) and P. iranica (A. scoparia and P. atlantica) are reported.

Septoria tritici blotch (STB) disease caused by the fungal pathogen Zymoseptoria tritici, is one of the most devastating wheat diseases in high rainfall areas. Study on virulence factors and genetic dynamics of the pathogen population in disease hot spots is assumed as main actions towards effective and durable genetic resistance in breeding programs for STB resistance, which could be achieved by monitoring virulence on differential wheat genotypes within STB trap nurseries. In order to monitor virulence factors of the fungal pathogen Z. tritici as well as efficacy of Stb genes to pathogen populations, response of 26 international differential wheat genotypes was evaluated under natural infection condition of trap nurseries in STB hot spots of Moghan, Dezful and Gorgan during three consecutive years of 2019-2021 based on 00-99 double digit scale. Furthermore, seedling reaction of differentials to Z. tritici isolates was investigated under greenhouse condition. The results showed that virulence pattern of pathogen populations was differed in all three locations as well as the three years of study. Based on the seedling and adult plant results, the highest virulent Z. tritici population was observed in Moghan and then in Dezful, whereas the pathogen dominated in Gorgan displayed the lowest virulence among the populations. Results of this research showed that various combinations of Stb resistance genes carried by the differential genotypes M3 (Stb16q & Stb17), KM 7 (Stb16 (S23)), Cs synthetic (Stb5), Kavkaz-K4500 (Stb6, Stb7, Stb10 & Stb12), Flame (Stb6), 3HD-138 (Stb18 (S25-winter type)), Oasis (Stb1), TE 9111 (Stb6, Stb7 & Stb11), Veranopolis (Stb2 & Stb6), Tadinia (Stb4 & Stb6) and KM 41 (Stb17 (S24)) could be used for producing wheat cultivars effectively resistant to Z. tritici populations in studied locations within breeding programs.

This study was carried out to determine the resistance and relative fitness of susceptible and resistant mustard biotypes collected from wheat fields of the Gilane-gharb region in Kermanshah province. Weeds had a long history of exposure to common broadleaf herbicides during the last five years. The herbicides studied included thribenurone methyl (Granstar) and 2,4-D+ MCPA. The result of preliminary studies identified one biotype had multiple resistance to both herbicides Granstar and 2,4-D+ MCPA and one biotype had resistance to Granstar only. Fitness studies were performed in two parts in the greenhouse. In the first part, plant dry matter, leaf area and plant height change of resistant and susceptible biotypes were compared under no competition with wheat condition and in the second part, the growth of susceptible and resistant biotypes of wild mustard weed in competition with wheat. Dry weight and height were measured in both plants. According to the results, the susceptible biotype was superior to the resistance biotypes in terms of the studied traits under no competition with wheat and susceptible biotype had higher dry weight, height, and leaf area rather than the resistant biotypes. Similarly, the susceptible biotype was superior to resistant biotypes in terms of growth under competition condition and, wheat had less growth in competition with susceptible biotype rather than resistant ones. Overall, the results of this study indicated that the emergence of resistance reduced the fitness of resistant wild mustard compared to the sensitive biotype.

To provide suitable models for predicting the temporal progress of barley leaf stripe disease caused by Pyrenophora graminea, epidemiological studies were conducted in 2019-2021. The temporal progress of disease was examined in five cultivars (Zehak, Nimroz, Auxin, Nowruz and Izeh) of barley in a randomized complete block design with four replications at Golestan Research Station in Khuzestan Province. Well-known epidemiological models such as Monomolecular, Logistics, Log-logistics, Gampertz and Weibel were used to assess the disease progress. The results showed that, in all cultivars, the log-logistic model is the most proper model in describing disease progress. In order to determine crop loss caused by barley stripe disease, 1000-kernel weight, yield and area under disease progress curve (AUDPC) during the growing season were measured. The results showed that the integral model using AUDPC as an independent variable and the loss percentage as a dependent variable in the Nowruz cultivar (L=33.241+0.0002AUDPC) can justify 50% of AUDPC changes against crop loss. In the multivariate model, disease severity at different stages was considered as an independent variable and yield was considered as a dependent variable. This model had high efficiency in estimating the amount of yield. The results also showed that disease severity in the early stages of disease symptoms and after heading is more important than other phenological stages in yield estimation. This multivariate model (Y = 4836.17 – 38.51X1- 33.78X7+ 16.83X28- 26.56X35) could explain more than 90% of changes in disease severity versus crop yield.

Fusarium head blight is one of the most important fungal diseases of small grains throughout world, which not only reduces the yield, but also causes quality losses through the production of various mycotoxins. The aim of this study was to isolate and identify the Fusarium head blight disease agents and to evaluate the effect of seeds infection by different isolates of Fusarium and deoxynivalenol compound on the traits related to seed germination. In order to identify wheat seed-derived Fusarium causing this disease from the fields of Zanjan, Markazi, Tehran, Alborz, Hamedan, Fars, Sistan and Baluchestan, Kermanshah and Khuzestan provinces were sampled according to the International Seed Testing Association (ISTA) rules. Then, the ability of trichothecene prodcution and the presence of genes involved in deoxynivalenol trichothecene biosynthesis and the level of deoxynivalenol production on rice medium were evaluated by High-performance liquid chromatography (HPLC). A total of 15 isolates were identified based on morphological and molecular characteristics as F. graminearum (12 isolates) and F. culmorum (3 isolates). The results showed that only 40% of the isolates had ability to produce trichothecene, and the levels of deoxynivalenol production was in the range of 1650-3500 μg.kg-1. The results of the standard germination test showed that seed treatment with different isolates of Fusarium affected the germination and seed vigor indices and reduced the seed quality and seedling health. The findings of this research provide new perspectives on the effect of the level of deoxynivalenol secreted by Fusarium on the quality characteristics of seeds and the rate of disease progress.

The Mediterranean flour moth, Ephestia kuehniella is widely used in rearing parasitoids and predators. Therefore, it’s nutritional and immunity indicators and its defense potential against pathogenes are important. Therefore, in this research, the effect of a standard diet including a mixture of wheat flour (68%), wheat bran (29%) and yeast (2%) as well as the combination with four types of vitamins A, C, E and D3 (1%) on the nutritional and safety index for pathogenes were evaluated. In this research, by measuring the blood cells of second, third and fourth instar larvae fed with different diet, the sensitivity of third instar larvae to different concentrations of Bacillus thuringiensis, Beauveria bassiana and Nucleopolyhedrovirus (NPV) was obtained by LC50 and LT50 values. In the evaluation of nutritional index on third instar larvae of Mediterranean flour moth, the highest relative growth rate, relative consumption rate, efficiency of conversion of eaten food and efficiency of conversion of digested food were observed in larvae fed in standard diet with vitamin C. Also, the LC50 and LT50 values resulting from the effect of different concentrations of B. bassiana, B. thuringiensis and NPV virus on the third instar larvae of the Mediterranean flour moth showed that the least effect was on the larvae fed on the standard food dietincluding vitamin C followed by vitamin D3. Therefore, in the reproduction and rearing of this host in the production of biological agents, it is recommended to use food supplements containing vitamin C and D3.

In order to evaluate the effectiveness of chemical control in the management of Fusarium diseases of corn, the present study was conducted using eight fungicides including Carboxin-Tiram (Vitavax -Tiram, 75% WP) as reference fungicide, Difenoconazole (Dividend DS 3%), Tebuconazole (Raxil DS 2%), Azoxy-strobin + Difenoconazole (Ortiva Top SC 32.5%), Trifloxystrobin (Flint WG50%), Protioconazole + Tebuconazole (Lamardur FS40%), Fludioxonyl + Metallaxyl M (Maxim XL FS) and Azoxystrobin + Metalaxyl M (Uniform SE 44.6 %) in three phases: laboratory, growth chamber and field. According to the results, all fungicides used in this research showed significant performance and effectiveness in control of Fusarium corn diseases compared to check in most of the traits evaluated, and application of them recommended as seed treatment before planting. In laboratory, Maxim and Raxil were considered as the most effective fungicides comparing the reference fungicide, Carboxin-Tiram. The most effective fungicides in growth chamber were Maxim, Lamardor, Ortivatop and Dividend, each of which showed higher efficiency than the reference fungicide in one or more traits. In field investigations in Golestan province, Maxim, Uniform and Ortivatop (with 93.9, 91.4 and 88.2% of check, respectively), in Ardabil province Maxim and Lamardor (with 51.5 and 41.7 % of check, respectively) and in Mazandaran province, Lamardor and Raxil (with 54.4% and 43.5% of check, respectively) were more effective compared with the infected control and showed better efficiency than the reference fungicide in most traits.

The greater wax moth, Galleria mellonella is one of the most important pests of beehives in Iran and the world. Which leads to the death of weak honey bee colonies. Also, this insect is an important laboratory host for the isolation and mass production of the entomopathogenic fungi and nematodes. In this research, the effect of pollens of different plants including poppy, wild rapeseed, rapeseed and apple in artificial diet, were evaluated on some physiological and biological parameters of this insect. The highest amount of the last instar larval gut protein was recorded in the diet containing poppy pollen (20.22 mg/ml) and no significant difference was observed between the other treatments. The highest relative activity of digestive alpha-amylase and pectinase in the last instar larval gut was related to the diets containing poppy pollen (100 %), and the lowest relative enzymes activity was recorded in the diet containing rapeseed pollen (51.12 and 76.35 %, respectively). Larvae fed with the diet containing poppy pollen and the resulting pupae had a higher weight than the other diets (325 and 175 mg, respectively). The highest percentage of larval survival and pupation was related to the diets containing poppy (77.5 and 77.5 %), apple (62.5 and 70 %), rapeseed (52.5 and 47.5 %) and wild rapeseed (47.5 and 30 %) pollens, respectively. However, there was no significant difference in the percentage of adult emergence in different diets. Consequently, the diets containing rapeseed and wild rapeseed pollens compared to poppy and apple, are not suitable diets for rearing G. mellonella and it is better to use poppy pollen in the preparation of artificial diet for the mass rearing of this insect.