نشریه پژوهش های کاربردی در گیاه پزشکی
سال چهارم شماره 1 (بهار 1394)

Leaf rust is one of the important wheat diseases which damages its production. Development of resistant varieties is an effective، environmentally friendly and low costly method for reducing disease damage. The aim of this study was to isolate and sequence Lr29 and Lr47 genes transferred to wheat from Agropyron elongatum and Triticum speltoides، respectively، in seven wheat lines with different levels of resistance to leaf rust. Using a specific primer pair، a fragment with length of 396 bp was isolated and sequenced from Lr47 gene in the studied lines having five open reading frames (ORF). The second ORF encoded a protein with length of 37 amino acids which showed 36% homology with wheat agglutinin antimicrobial protein. Alignment of the Lr47 sequence with NCBI data revealed 99% homology with Triticuma estivum sucrose synthase type I gene sequence. Nucleotide diversity of Lr47 gene was 0. 0041 and five single nucleotide polymorphism were identified among the seven lines. Bolani showed a large deletion with length of 48 nucleotide at 3’ non-coding end of the gene which could differentiate this line from the others. The length of isolated fragment from Lr29 gene was 160 bp which showed 91 and 90% similarity with acetyl CoA carboxylase gene from wheat and Aegilop stauschii، respectively. Twenty eight single nucleotide substitutions with nucleotide diversity of 0. 0589 were detected in Lr29 gene. Synonymous/non synonymous substitution ratio in Lr47 and Lr29 gene indicated negative and positive selection in the studied line for these genes، respectively.

Trunk diseases are among the important diseases of almond trees, considered as a potential threat for the almond cultivation and production. Given the incidence of the trunk diseases on almond trees in the orchards of East Azarbaijan province, the identity of fungal species associated with disease symptoms mainly remain unknown. In this study, the fungal species associated with the trunk diseases on almond trees in East Azerbaijan province were characterized using morphological and molecular data. A total number of 115 fungal isolates were recovered from diseased samples showing canker and wood decay and discoloration symptoms. The identity of the fungal species were determined by using both morphological and sequence data of the ITS-rDNA region. The results revealed Collophora hispanica as the dominant species amongst the fungal groups associated with almond trunk diseases in this region with the isolation frequency of 61.73 percent. In addition fungal species including Cytospora chrysosperma, Truncatella angustata, Beauveria bassiana, Acrostalagmus luteoalbus, Quambalaria sp., Clonostachys rosea, Fusarium proliferatum, F. acuminatum, F. torulosum, F. solani, F. avenaceum, F. oxysporum, Paecilomyces variotii, Trichothecium roseum, Phellinus sp. and Phoma sp. were isolated with lower frequencies. All of the species, except, C. chrysosperma, P. variotii, C. rosea, T. roseum and Phellinus sp. represent new records on almond for Iran. Additinaly, T. angustata, F. torulosum, F. proliferatum and Quambalaria sp. are newly reported on almond all over the world. With the identification of fungal species associated with almond tree decline in this region it will be possible to evaluate their pathogenicity on almond and eventually practice suitable management strategies for this complex disease.

In order to identify the species and host range of Erysiphaceae fungi in Ardabil province, infected plant specimens belonged to 47 plant species were collected during 2012-2013 and the species identified according to the new treatment available in taxonomy of this family. Totally, 32 species and 9 genera belonged to Erysiphaceae were identified and described. Among taxa, two species Erysiphe howeana and Neoerysiphe galeopsidis on Oenothera sp. and Ballota nigra were reported for the first time in Iran, respectively. Two species Golovinomyces cf. orontii and Golovinomyces macrocarpus were introduced as powdery mildew agent on Viola tricolor and Tanacetum balsamita in Iran, respectively. Previously these species were reported as Oidium violae and Erysiphe cichoracearum, respectively. Also, 19 species are new for Ardabil province mycoflora. Among 32 identified species in this study, 10 fungal species had infected more than one host plant that Blumeria graminis had the widest range with five host plant species.

Sunn pest Eurygaster integriceps Puton is the most important pest of wheat and barley in Iran. Using biological control agents, within which egg parasitoids are the most promising agents, is an effective tactic of management of this pest. For optimal use of biological control agents, one needs to beware of efficacy of them in different ecological conditions. Regarding priority of the parasitoids in their emergence in wheat fields compared to their host in spring, they are in a high risk of encountering with durations of host absence early season; hence in this study we evaluated the effect of different intervals of host unavailability upon the egg parasitoids in terms of parasitism rate. The parasitic wasp, Trissolcus grandis (Thomson) (Hym., Scelionidae), which is dominant species in Iran wheat fields was chosen for experiments. The wasp specimens were collected from Garamalek and Kujuvar villages, located in west of Tabriz. The experiments were conducted under laboratory conditions (25±1ºC, 50±10% RH and 16L: 8D h photoperiod) with five treatments including a control (complete access of wasps to the hosts), access every other days, every third days, once a week and complete access following a six day prevention period in 15 replications. The results revealed that parasitism rate decreases by increasing unavailability intervals of host. Results showed that a partial compensation was occured in all treatments except young females of T. garndis in the second treatment that the wasp could completely overcome host deficiency of the previous days during first few days of her lifespan.

Early blight is one of the most common and important disease that causes damage to most Solanaceos plants. At the present time, the most practicable way of control of the disease is using fungicides. Due to the importance of alternarios and excessive use of chemical compounds, this study was conducted to evaluate the effectiveness of non-toxic compounds in controlling the disease and comparing them with common fungicides. In this study, the effect of NaHCo3, CaCl2 salts, biological compound of Bacillex, clove oil, Rovral Ts and Dakonil fungicides on growth of fungal species Alternaria solani and A. alternata in vitro and the disease severity of resulting them in greenhouse have been investigated. The results showed that all the compounds inhibited the mycelium growth of two species of fungi in vitro except Daconil. The maximum growth inhibition was done with Rovral Ts and sodium bicarbonate at concentration of 30 ppm and 35 mg/ ml respectively. Greenhouse experiments indicated that tested compounds were effective in the disease severity reduction. Maximum reduction of disease severity in greenhouse due to Rovral Ts, Daconill, sodium bicarbonate, calcium chloride, Bacillex and clove oil were 33/88, 93, 33/92, 93, 33/70 and 74%, respectively.

Characteristics such as lower developmental time, higher fertility and a large body size of natural enemies as biological control agents are important for mass rearing. Menochilus sexmaculatus (Fabricius) (Col.: Coccinellidae) is one of the major predators of pests in the orchards of Iran. The effect of six constant temperatures of 17.5, 20, 22.5, 25, 27.5 and 30 ºC were investigated on the development of the predator by feeding on the Pomegranate green aphid Aphis punicae (Hem.: Aphididae) under laboratory conditions (65 ± 5 RH and 16L: 8D h). The developmental time of M. sexmaculatus were 26.83± 0.61, 19.35 ± 0.23, 16.02 ±0.16, 11.66 ± 0.12, 10.45 ± 0.20 and 13.35 ± 0.33 days on above mentioned temperatures, respectively. The results showed that developmental time decreased with increasing temperature to 27.5 ºC. The lowest mortality was observed at 22.5ºC among the above-mentioned temperatures. The results indicated that there were significant differences for developmental times in different temperatures. Survival rate decreased away from the desirable temperature, 27.5 ºC, in both higher and lower orders. Lower temperature thresholds for eggs, larvae, pupae and adults were 10.69, 12.22, 12.83, 11.55ºC and thermal constants for egg, total larval period, pupa and egg to adult were 32.25, 83.33, 33.33, 166.66 degree-days, respectively, by feeding green pomegranate aphid. The results showed that optimum temperature were 25 to 27.5ºC for the rearing of the lady beetle.

All members of the genus Azospirillum are soil inhabitant and known to be incredibly efficient nitrogen fixers. High populations of these bacteria in the soil are important to increase plant growth. Various factors can affect the natural balance of the soil ecosystem, and reduce soil populations of beneficial bacteria, which indirectly reduces the growth and beauty of the plant. One of the major factors affecting soil microbial populations is agricultural pesticides. This study was conducted to evaluate the effect of five different concentrations of benomyl and paraquat (250-5000 mg/L) at various temperatures (25-45 Ċ) on indigenous bacterial strains of Azospirillum irakense as a nitrogen fixing bacteria in laboratory and glasshouse conditions. Experiment was performed in a factorial design with four replications. The results showed that both pesticides at a concentration of 5000 mg/L are completely lethal to the bacterium and caused complete cessation of growth. At lower concentrations, both pesticides could significantly reduce bacterial population growth but it didn’t stop bacterial growth. In the glasshouse conditions, both pesticides at any concentration could not remove bacteria from soil but significantly reduced the population of bacterium in the soil. A strong correlation was observed between the temperature and inhibitory effects of pesticides and the rate of inhibition was significantly increased with increasing temperature.

In this study, lethal effects of indoxacarb and methoxyfenozide were assessed on Colorado potato beetle. To do the bioassays, potato leaflets were dipped in aqueous suspensions of the insecticides and the larvae were transferred on the leaflets after drying. The results were recorded 24 and 72h after treatment for indoxacarb and methoxyfenozide, respectively. LC50 of methoxyfenozide for the 1st instars was 80.6 mg ai/l and LC50 values for indoxacarb were 4.5, 6.85, 9.42 and 7.28 mg ai/l for 1st, 2nd, 3rd and 4th instars, respectively. LC50 value of methoxyfenozide for 1st instar was relatively high; therefore lethal concenteration was not estimated for next instars. Because of the importance of sublethal effects in insect growth regulators (IGRs) application, the sublethal effects were evaluated for methoxyfenozide by using its LC1 and LC7. First instars were fed on treated leaves for 48 or 96h and then on untreated leaves; and were monitored until adult stage. Fecundity of these adults was evaluated. The number of larvae developed to prepupae and adults was significantly lower in sublethal concentrations of methoxyfenozide compared with control. The treated larvae did not reach next generation. The results indicated that indoxacarb and methoxyfenozide were effective against Colorado potato beetle; and if they perform equally well in the field, they can be suitable candidates for management of this important pest.

In recent years, the use of plant derivatives including essential oils and plant extracts has been taken into consideration as an alternative to chemical pesticides for pest control. In this study, antifeedant activity of purple nutsedge, Cyperus rotundus L. essential oil was investigated against sawtoothed grain beetle, Oryzaephilus surinamensis L. and khapra beetle, Trogoderma granarium Everts by using flour disc method, under laboratory conditions (27±2°C, 65±5% RH and continuous darkness). Results showed that feeding indices were affected by essential oil and the relative growth rate, relative consumption rate and efficacy of conversion of ingested food decreased for both insects with increasing concentration. The efficacy of conversion of ingested food decreased from 7.80% and 6.18% at control to 3.05% and 3.68% at highest concentration for O. surinamensis and T. granarium, respectively. The feeding deterrence index for both insects increased from 32.57% and 39.02% at the lowest concentration to 46.85% and 49.33% at highest concentration, respectively. According to these results, the essential oil affected test insects in two ways; feeding deterrence and post ingestive toxicity. The results demonstrated that C. rotundus essential oil could be used as a probable substitution to chemical pesticides for stored products protection against storage pests.

Residual insecticides have traditionally been used to control the stored cereals, through treating the structure of stores or surface of the commodities. The efficacy of abamectin, permethrin, thiamethoxam, chlorpyrifos and malathion were evaluated against rice weevil, Sitophilus oryzae (L.) via the insecticide-treated surface. Then, persistence of their insecticidal property, their lethality against the starved adults and their effect against the number of F1 adults were investigated. The LC50s of abamectin, permethrin, thiamethoxam, chlorpyrifos and malathion were 1.04, 38.7, 3.56, 0.16 and 0.86 mg ai/l, respectively, based on probit analysis of the 24 hours post-treatment data. Decrement of F1 progenies were between 38 to 87 % (both in low and high concentrations of chlorpyrifos, respectively). In persistence experiments, thiamethoxam (17% reduction of mortality) and malathion (93% reduction of mortality) were the most and least persistent insecticides, respectively. Susceptibility to some concentrations of chlorpyrifos, malathion and thiamethoxam were significantly increased as a result of starving the insects. Efficacy of low concentration of thiamethoxam (1.25 mg ai/l) was increased as consequence of starving the beetles for 14 days (26 to 83%). Our results demonstrated that effectiveness of the residual insecticides can be increased through their appropriate application and sanitation of grain stores.

Seed eater insects are one of the main factors which could damage range plants including legumes (Fabaceae), that cause many difficulties in producing to healthy seeds. In this study, infected seeds of pasture legume plants (Fabaceae) were collected from different regions in East-Azarbayjan province during 2010-2013. Collected seeds were transferred to the laboratory for rearing and identification. Based on the identification of host plants and their seed eaters, a total of 153 legume specimense (belonging to 70 species) were collected across rangelands of which 110 specimense (belonging to 53 species) was positive for seed eating insects. During the survey, in total 18 species belonging to 11 genera of Apionidae weevils were identified as follows:Aspidapion aeneum (Fabricius), Catapion schneideri (Tournier), Catapion sp., Eutrichapion sp., Fremuthiella iranica (Bajtebov & Fremuth), Holotrichapion gracilicolle (Gyllenhal), Ischnopterapion cognatum (Hochhuth), Mesotrichapion subglabrum (Desbrochers), Perapion radiolus (Marsham), Perapion sp., Perapion violaceum (Kirby), Protapion dissimile (Germar), Protapion fulvipes (Geoffroy), Protapion schoenherri (Boheman), Protapion trifolii (L.), Pseudoprotapion elegantulum (Germar), Pseudoprotapion ergenense (Becker), Rhopalapion longirostre (Olivier).

Plodia interpunctella Hubner (Lepidoptera: Pyralidae) is a cosmopolitan species known to infest a wide range of dried plant materials, including legumes and cereals. In this study, after confirmation of the presence of alpha-amylase gene in samples using gene specific primers, total RNA was extracted from fifth instar larvae of P. interpunctella, grown on the five different nutrition regimes including pistachio, white mulatto, plum, wheat and artificial diet (as control). After synthesis of cDNA, change in gene expression was studied with Real-time PCR assay. PCR performance test indicates 99 and 98% amplification efficiency for SiAmy and SiAmyC primers, respectively. Different nutrition regimes caused differential change in the expression of the gene. In comparison with the control, pistachio regime caused 5% increase in the expression of the alpha-amylase gene, wherease 10%, 27% and 60% decreases were observed in the larva grown on plum, wheat and mulatto respectively. Maximum variation in expression of alpha-amylase gene was observed in the larvae fed on mulatto. The results showed that the inhibition of alpha-amylase gene expression varied in the different sources of glucose in larvae fed on different diets and there was a negative correlation between the amount of sugar in the diet and alpha-amylase gene expression.

Ladybird, Coccinella septempunctata (L.) (Col.: Coccinellidae) is a well-known predator which has an effective role in biological control of pests. Biology of different stages and fecundity of C.septempunctata were studied on Macrosiphum rosae under laboratory conditions at three constant temperatures (14, 25 and 31°C), relative humidity of 60 ± 5 % and a photoperiod of 16:8 (L:D) h with 100 repetitions. Therewas no oviposition at 14°C. Lifetime oviposition and mean ovipositon rate were highest at 25°C and zero at 14°C. The average total fecundities of C. septempunctata at 25 and 31°C were 307.46 and 125.8 (eggs / female) and the mean number of eggs per female per day was 24.52 and 10.95 eggs, respectively. The results of the experiment showed that mean developmental periods from egg to pupa were longest at 14°Cand shortest at 31°C. The mean total life span for females and males were 69.32, 67.97 days at 14°C; 53.2, 39.19 days at 25°C and 49.1, 36.52 days at 31°C, respectively. In addition, preimaginal development rates of C. septempunctata were fitted to the regression linear model. Low developmental threshold and thermal constant were estimated to be 9.8°C and 250 day-degrees Celsius, respectively.

West Azerbaijan Province is a mountainous area in the North West of Iran that has a high potential for the production of grains/cereals. The diversity of active aphids species and their coccinellids predators in wheat farms of this province was studied for two years during 2010 and 2011. The present study identified six harmful species of aphids and five species of ladybird beetles being their main enemies at different wheat growth stages and different sampling dates. In 2010, Schizaphis graminun (Rondanii) species was the most frequently found species and was considered as dominant species in the area. The highest species richness of the collected grains/cereals aphids was recorded five species in the early of May in 2010. The highest degree of Shannon diversity index (1.81) was also related to 2nd of May, 2010 and the least amount of the same index (0.65) was found in 1st of July in the same year. In 2011, Metopolophium dirhodum (Walker) species had the most frequency rate and was regarded as the dominant species. The highest species richness of the collected aphids of the grains was observed during the mid-June in 2011. The highest degree of Shannon diversity index (1.25) was related to 15th of April 2011 and the least amount of the same index (0.81) was found in 11th of March in that year.

During 2011 to 2012, different Pome orchards in Isfahan province were surveyed and the samples with fire blight symptoms such as water soaking of infected tissues, necrosis, wilt and tissue necrosis, scorched and in some cases death of the entire tree, were collected. Forty nine bacterial strains were isolated using NA, SNA and EMB media. Based on standard physiological and biochemical tests, the isolates were identified as Erwinia amylovora. In the PCR assayisolates were identified as E. amylovora, based on 1000 bp DNA fragments using A/B specific primers. In rep-PCR assay representative strains produced different fingerprints patterns using REP, ERIC, BOX primers. The results of this study demonstrated that fire blight disease is distributed in Isfahan province and collected E. amylovora strains from various regions of Isfahan province are genotypically homogenous with more than 71% similarity.