Temperature-dependent life table studies were performed to evaluate the direct effects of rising temperatures (20, 22.5, 25, 30, 35, 37.5, and 40 °C ± 0.5) on Helicoverpa armigera (Hübner) (Lep: Noctuidae). The results indicated that H. armigera could successfully survive and reproduce at all temperatures tested except at 37.5 and 40 °C (at 37.5 °C, no adults emerged, and at 40 °C, no eggs hatched). However, a significant difference was observed among the mean life table parameters of H. armigera at survived temperatures. The constant temperatures of 22.5 and 25 °C were considered the optimum degree of eggs laid by females of H. armigera. The intrinsic rate of rise (r) at the specified temperatures ranged from 0.080 day−1 at 35 °C to 0.145 day−1 at 22.5 °C. In addition, the value of the net reproductive rate (R0) of H. armigera at the different temperatures tested varied from 9.22 offspring at 35 °C to 501.01 offspring at 22.5 °C. Furthermore, the values of the gross reproductive rate (GRR) were significantly different at the tested temperatures, and the lowest and highest values of this parameter were obtained at 35 °C (42.18 offspring) and 22.5 °C (1056.44 offspring), respectively. Immature mortality increased with increasing temperature. The results obtained in the present study may provide insight into predicting population dynamics and the efficacy of the subsequent management programs for this pest.
Potyviruses cause severe diseases in different crops around the world. During March and April 2018, 90 basil and 21 weed samples were collected from basil fields in the eastern provinces of Iran. The total RNA of samples was extracted, and RT-PCR was performed using degenerative primers of potyviruses. Sequence analysis showed that positive samples were most closely related to Turnip mosaic virus (TuMV) or Bean yellow mosaic virus (BCMV). Subsequently, specific primers of TuMV were used to amplify a 980 bp amplicon in a sample of Ocimum basilicum and Malva sylvestris. Furthermore, a 950 bp amplicon was also detected in six samples of O. basilicum when specific BYMV primers were used for the PCR assay. All amplified PCR products were cloned and sequenced. According to CP-based phylogenetic analysis, two Iranian isolates of TuMV were placed in the Asian BR group. Five Iranian isolates of BYMV were classified in the broad bean group, and another isolate was placed in the general group. The homology matrix also showed that an isolate from India had the least nucleotide identity (80%) with the Iranian isolate, while among the Iranian isolate, SIB9 was very close to the Japanese isolate (98%). According to recombination analysis, three Iranian isolates of BYMV were recombinant. Sequence analysis of the TuMV isolate (SIB1) showed that it shared 99% nucleotide identity with the Chinese isolate. This survey is the first report of two potyviruses, including TuMV and BYMV, infecting O. basilicum in Iran.
Wheat stem rust, caused by the biotrophic pathogen Puccinia graminis f. sp. tritici (Pgt), is an important disease worldwide. To overcome host immunity, Pgt secretes several effectors, including AvrSr35 and AvrSr50. These effectors are recognized by resistant cultivars carrying corresponding receptors, resulting in incompatible reactions. In this study, we assessed the resistance of Sr35- and Sr50-carrying wheat monogenic lines to 30 Pgt isolates through inoculation with urediospores of pure isolates. Virulence analyses were evaluated for resistant IF 0-2 and susceptible 3-4 reactions and revealed that Pgt20-6 and Pgt20-12 isolates showed increased virulence on the Sr50-carrying line. The presence of AvrSr35 and AvrSr50 genes was assessed in the genome of all isolates through PCR. Visualization of amplified fragments on agarose gel confirmed the presence of AvrSr35 and AvrSr50 genes in the genome of all 30 isolates. Despite the presence of Avr genes in all isolates, the lack of active recognition for two isolates on the Sr50-carrying line suggested point mutations in their sequence. Sequencing analysis of AvrSr50 confirmed an A178T mutation unique to these two virulent isolates. Homology modeling based on the solved crystal structure of AvrSr50 showed a nonsynonymous mutation at the protein surface that may be involved in the interaction with Sr50 to escape from recognition. This study showed the constant genetic change of fungus and recalled the necessity of continuously monitoring the fungal population to take appropriate strategies in wheat breeding programs.
Meloidogyne javanica and Ralstonia solanacearum are the highly specialized soil-born plant parasites with economic importance causing root-knot and bacterial wilt diseases in tomatoes, respectively. The occurrence and intensity of the bacterial wilt escalated in the presence of root-knot nematodes and R. solanacearum concurrently detected in different vegetable crops. Sampling and preparation of leaf extract were done to investigate the activity of catalase (CAT), superoxide dismutase (SOD), and peroxidase (POX) enzymes at 24, 48, 72, and 120 hours post-inoculation (hpi) of tomato plants with R. solanacearum and M. javanica. The enzyme activity was measured at each time interval. The CAT and SOD enzymes exhibited maximum activity levels at 120 and 48 hpi in the nematode treatment, respectively. Meanwhile, the levels of POX enzyme peaked at 48 and 72 hpi in the nematode and nematode-bacterium treatments, respectively. Pathogen stress eventually led to a decrease in the SOD and POX enzymes 120 hours after inoculation and a significant increase in CAT during nematode-bacterium treatment. The results revealed apparent enzyme activity variations in tomato plants infected with both pathogens at different time intervals after inoculation.
Root-knot nematode has a widespread distribution and has caused significant damage, as in some cases, led to complete crop loss. Environment-friendly and safe methods are essential for the replacement of chemical nematicides. In the present study, the lethal effect of aqueous extracts from eucalyptus (Eucalyptus camaldulensis) and chinaberry (Melia azedarach), which are locally available plants, on second-stage juveniles (J2) of the root-knot nematode, Meloidogyne javanica was investigated under laboratory conditions. For this purpose, concentrations of 1000 to 7000 ppm were evaluated on 100 numbers of J2 at two different time intervals, two four days, using a factorial experiment (concentrations of 1000 to 7000 and times of two and four days after extract exposure) within a completely randomized design with three replications. The median lethal concentrations (LC50) for each extract were calculated. The results of this study indicate a significant correlation between the increased mortality rate of juveniles and the concentration and exposure period. The highest concentration exhibited the best results after four days, with mortality rates of 73% and 68% for M. azedarach and E. camaldulensis compared to the control, respectively. The probit analysis revealed that LC50 values were 5044 and 5694 ppm for chinaberry and eucalyptus, respectively. No significant changes were recorded in the internal organs of the dead larvae, except for the contraction in parts of the intestine and their straight standing. In general, plant extracts present a promising method for managing M. javanica.
Using pheromone traps is one of the standard methods to control the mango fruit fly, Bactrocera zonata (Saunders) (Diptera: Tephritidae). The lower efficiency of traps has made it inevitable to consider more efficient methods of controlling this pest. This study investigated the effect of integrated control treatments. The experiment was a randomized block design with split plots, including four main treatments, four sub-treatments, and five replications to control this pest. Using the pheromone traps alone (two types of traps: McPhail and Delta with two different dispensers: chipboard sheets (neopan chipboard sheets) and glass tubes), the combination of traps and shade-spraying, the combination of traps, and trunk spraying by poisonous bait (a mixture of insecticide and hydrolyzed protein), and finally the combination of traps, shade-spraying, and trunk spraying were compared. The results indicated that applying traps alone was the least effective, and the combination of shade-spraying, trunk spraying, and pheromone traps was the most effective treatment for controlling the pest. Concerning the pheromone traps and dispensers, the McPhail trap was more effective than the delta trap, and the chipboard dispenser was more effective than the glass tubes regarding the number of pest individuals captured and, consequently, the rate of damage reduced. According to the present study’s findings, combining different control measures with pheromone traps, replacing delta traps with McPhail ones, and chipboard dispensers with glass tubes would lead to appropriate control of B. zonata.
Anthracnose, a leaf disease caused by Colletotrichum species, is a major threat to ornamental plants worldwide. This study aimed to identify the causal agent of anthracnose affecting Ficus benjamina plants in greenhouses around Amol, Mazandaran Province, northern Iran. Fungal isolation from infected leaves revealed a Colletotrichum species, which was confirmed as C. karstii through morphological, cultural characteristics, and partial β-tubulin gene sequencing. Pathogenicity tests fulfilled Koch's postulates by reproducing anthracnose symptoms on inoculated F. benjamina plants. This study establishes C. karstii as the first reported causal agent of anthracnose on F. benjamina in Iran, contributing to a better understanding of C. karstii impact on Iranian ornamental plants.
The genetic diversity of Trichoderma species isolated from pistachio soils in Kerman Province was investigated. A total of 131 isolates were obtained and identified at the species level by analyzing their morphological characters. Eighty-seven isolates were identified as Trichoderma harzianum and forty-four isolates as Trichoderma aureoviride. The sequences of their ribosomal RNA (rRNA) gene internal transcribed spacers (ITS), were determined and used as phylogenetic markers. The complete ITS nucleotide sequences of 17 selected isolates of T. harzianum and T. aureroviride were determined. Minimal rDNA-ITS sequence variation was observed, and molecular informative differences between T. harzianum and T. aureroviride were not found in phylogenetic analysis.. RAPD-PCR using the four random primers, OPA4, OPA3, A-5, and Pr3, was evaluated as a technique to separate and differentiate these two species. The four primers produced DNA bands for the 16 Trichoderma isolates, of which 81 (95.3%) were polymorphic, and four (4.7%) were monomorphic. The RAPD data was computed into a similarity matrix using the NTSYS computer program. The genetic similarity coefficient between pairwise isolates varied from 0.50 to 0.98 based on an unweighted paired group method of arithmetic average (UPGMA) cluster analysis. The results showed that all isolates were grouped into two main clades. In agreement with observation, data from morphological characteristics resulting in RAPD-PCR banding patterns revealed it was easier to identify and differentiate T. harzianum and T. aureroviride isolates. The RAPD-PCR technique was practical and efficient for routine high-resolution diversity studies for the two species.
Plastic mulches on the soil surface can impact the population and activity of soil microorganisms, such as Aspergillus species, by altering the temperature and humidity of the soil. In the present study, the effects of white and black mulches were examined on the population of Aspergillus flavus-clade in the soils of two pistachio orchards (35-year-old Fandoghi cultivar) with a surface drip irrigation system in Rafsanjan (Kerman Province, Iran). The experiment was performed as a randomized complete block design with three replications. The population of A. flavus-clade in the soil was measured monthly using the serial dilution method and SPDA culture medium. Identification and toxigenic isolates were screened using a coconut agar medium. The results indicated that white and black plastic mulches decreased the population density of A. flavus-clade in all sampling months except for December in the two pistachio orchards. In garden No. 1, the population of A. flavus-clade decreased 64 and 46 percent in August compared to the control in black and white mulches, respectively. However, in garden No. 2, this reduction was 48 and 35% in black and white mulches, respectively. Additionally, in plastic mulches, mainly black mulch, the population of toxigenic isolates exhibited a significant decrease in the soil compared to the control, especially during hot months. It is concluded that using plastic mulches, mainly black mulches, can reduce the population of A. flavus-clade in pistachio orchard soils and minimize contamination of pistachios with Aspergillus and aflatoxin.
Considering the low risk of botanical pesticides for humans and the environment, and their broad-spectrum pest control capabilities, it seems beneficial and necessary to consider these compounds in integrated pest management. Different plant parts produce different amounts of secondary metabolites that can have insecticidal properties. Therefore, by evaluating the effectiveness of substances extracted from different parts of plants, it is possible to open a window to identify important effective substances. This study investigated the insecticidal activity of Melia azedarach L. extracts (flowers, fruit growth stages, and leaves) against Aphis fabae Scopoli using different solvents (polar protic, dipolar aprotic, and non-polar). The highest mortality percentage among methanolic extracts was found in the flower extract (77.74±5.75%), in n-hexane extracts it was in the ripe fruit extract (76.18±4.09%), and in acetonic extracts it was in the flower extract (66.48±5.91%). Results indicated that all three plant parts' methanolic extracts showed the most potent insecticidal effects.
Acarapis mites are one of the world’s most important honey bee pests. A polymerase chain reaction (PCR) was used to amplify the mitochondrial cytochrome oxidase I gene to investigate the infestation of Iranian honey bee Apis mellifera meda populations with Acarapis species. From 2020 to 2022, bee workers were collected from apiaries across nine country provinces. The PCR assays were performed with four primer sets, and Acarapis-positive samples were sequenced to identify species. Acarapis woodi showed the highest infection rate, while A. dorsalis was less, and no infection with A. externus was observed. Different sets of primers were used in this investigation. Two primer sets showed different results: the prevalence of A. woodi ranged from 58.33 to 75% with primer set ACR2 and 25 to 50% with primer set ACR1. This is the first report on the existence of Acarapis mites in Iranian A. mellifera based on molecular techniques.
During the survey of mango (Mangifera indica, Anacardiaceae) trees in Sistan and Baluchestan, Hormozgan, and Kerman Provinces, the occurrence of leaf spot diseases was observed. Symptomatic samples were collected and subsequently transferred to the laboratory for the purpose of isolating the causal agents. After surface sterilization of selected leaf tissues, small leaf pieces were transferred to potato dextrose agar (PDA). In order to achieve purification, single spore or hyphal tip methods were used. Based on morphological criteria and analyzing data from the ITS-rDNA and glyceraldehyde 3-phosphate dehydrogenase (gpd) gene regions, 118 isolates belonging to Alternaria alternata, Curvularia hawiiensis, and Exserohilum rostratum species were identified. Pathogenicity test was carried out by using detached leaf assay on leaf pieces of mango. After seven days, necrotic lesions were observed on inoculated leaves and fungal isolates were re-isolated and identified to confirm Koch's postulates. To the best of our knowledge, this study is the first report of C. hawaiiensis and E. rostratum as the causal agents of leaf spot on mango trees in Iran.
The spread of weed resistance to herbicides threatens both Iranian and global agriculture. In 2019, a study was conducted to ascertain the resistance of Vaccaria spp. to conventional herbicides used in wheat fields. The study employed a completely randomized design, which included five treatments and five replications. The 25 biotypes were collected from 16 cities across five provinces through a national call. To assess the resistance of these biotypes, herbicide treatments, including iodosulfuron + mesosulfuron (Atlantis), tribenuron-methyl (Granstar), 2,4-D + MCPA (U46 Combi-Fluid), bromoxynil + MCPA (Bromicide MA), and iodosulfuron + mesosulfuron + diflufenican (Othello), were applied at the recommended dose per hectare according to the Moss and Adkins evaluation method. Subsequently, a population distribution map was created using ArcGIS Pro software, categorizing biotypes into three groups: resistant, developed resistant, and sensitive to herbicides. The results indicated that seven biotypes (28%) were resistant to Granstar herbicide, two biotypes (8%) to Atlantis herbicide, and one biotype (4%) was resistant to Othello herbicide. Additionally, three biotypes (12%) were classified in the developed resistant group for Granstar herbicide, one biotype (4%) for Atlantis herbicide, and two biotypes (8%) for Othello herbicide. Notably, based on the evaluation criteria of Adkins and Moss, all collected biotypes were sensitive to the two herbicides, U46 Cambi Floyd and Bromicid MA.
Members of the genus Fusarium are considered highly destructive pathogens of common beans (Phaseolus vulgaris). This study aimed to identify the causal agent of the disease, confirm its pathogenicity following Koch’s postulates, and investigate the extracellular enzymes of F. solani. After conducting a field survey on common bean plants in Khorasan Razavi Province in August and September of 2021 and 2022 and isolating fungi, the isolates were identified as F. solani f. sp. phaseoli based on morphological traits and molecular analysis of the internal transcribed spacer region. Pathogenicity tests revealed the isolates causing symptoms such as yellowing, rotting, and wilting on common bean seedlings (cv. Derakhshan). Moreover, extracellular destructive enzymes, including pectinase and cellulase, were quantitatively assessed. The isolates exhibited cellulase activity more quickly and at higher levels than pectinase. Our findings indicated that the enzymes are key in inducing disease symptoms in the host plant.
Alfalfa mosaic virus (AMV, Alfamovirus AMV) is the type species of the genus in the family Bromoviridae and is transmitted in non-persistent manner by aphids. Based on the previous studies, four Iranian AMV isolates collected in Khuzestan Province phylogenetically were clustered into a distinctive group. One out of the four isolates (Kh.Be.A) was selected for further studies. This isolate was biologically characterized by inoculating a range of test plants from Solanaceae, Fabaceae and Chenopodiaceae families. Among inoculated plants, AMV induced symptoms on Nicotian glutinosa L., N. debneyii L., Datura maxima L. and D. stramonium L.. In molecular studies, the total length of the P2 gene of AMV was amplified using three specific primer pairs in the RT-PCR test and sequenced to be 2418 nucleotides. Sequence comparison of the P2 gene with counterpart sequences available in the GenBank showed that the AMV isolates are classified into three groups. Members of each group were divided into two subgroups, A and B. Group IIA comprise Iranian isolates together with two Australian isolates (LC485016.1 and MK913781.1). Sequence comparison of the P2 gene of the Kh.Be.A isolate with those of the two isolates- shared 96.8 and 95% nucleotide and 96.6 and 93.7% amino acid sequence identities, respectively. According to the result of this study, phylogenetic analysis based on the P2 gene indicates three main groups of AMV isolates occurring in different countries and plant hosts.
During a survey, a severe canker disease outbreak affecting Eucalyptus camaldulensis was found in various parts of Hormozgan Province, the south of Iran. The disease symptoms manifested through dark brown necrotic lesions, extensive cankers, longitudinal trunk cracks, wood discoloration, twig dieback, gummosis, and death. The disease incidence in the studied regions was 81%. This study aimed to characterize the disease, ascertain its etiological agent, and validate its pathogenicity using Koch’s postulates. Fungal isolations from symptomatic tissues yielded colonies consistent with a Paecilomyces sp., subsequently identified as P. maximus based on morphological traits and molecular analysis of the internal transcribed spacer nrDNA region and β-tubulin (tub2) gene. Pathogenicity tests demonstrated lesion development on healthy branches inoculated with mycelium plugs from P. maximus, confirming the association between the fungus and observed symptoms. Small brown lesions appeared on the inoculated branches during 15 to 18 days, proving that the fungus is the cause of the disease. P. maximus was only re-isolated from the inoculated symptomatic tissue. Notably, this study represents the first documentation of P. maximus causing canker disease on eucalyptus trees in Iran and globally.
The increase in scientific expeditions has led to the revelation of moth biodiversity across Iran. This research presents new country and provincial species records for two widespread moth families, Noctuidae and Erebidae. The genus Anumeta Walker, 1858 (Toxocampinae subfamily) has a Palearctic distribution range of 25 species. It now represents the Erebidae family with one additional species, Anumeta dentistrigata (Staudinger, 1877), found in Iran. The external and genital characters of this species are presented, along with information on its distribution, bionomics, and illustrations of the adult and female genitalia. Eight noctuid and erebid species with new provincial records are introduced, and their distribution, bionomics, and remarks, where necessary, are given. Further thorough investigations are needed to explore Iran's rich and yet not wholly known biodiversity, as highlighted by this investigation and previous contributions reporting new records from less explored regions in southern Iran.
