Journal of Applied Research in Plant Protection
Year:2017 | Volume:6 | Issue:3 |Papers Count:12

For assessing the lethal effects of abamectin and propargite on Moghan Population of Tetranychus urticae and persistence of their lethal effects on the bean plants, adult mites were treated in separated experiments. Leaf disks of bean plant were prepared and leaf dipping method was used for bioassays. Five concentrations of each acaricide were provided and 20 adult mites were used for each concentration in each replication and the experiment was replicated three times for each acaricide component. Unit of replication was a Petri dish including a bean leaf piece (2 cm ×2 cm) treated with acaricide concentration with ventilated lid which lined with water soaked cotton and 20 mites were placed on the leaf piece. Mite mortality was recorded 48 h post treatment. For evaluating the persistence of lethal effects of the acaricides on bean plants against T. urticae, bean plants were sprayed with concentration of twentieth of recommended field dose of each acaricide component, separately. Leaf disks were prepared from treated plants in different time intervals including 1, 3, 7, 10 and 21 days after treatments. 20 adult mites were transferred on each of the leaf disks and their mortality was recorded 48 h post transfer. The experiment was repeated three times and distilled water was used as control. Probit analysis of lethal experiment data revealed that LC20, LC50 and LC90 values were 0. 108, 0. 417 and 3. 26 ppm for abamectin and 0. 657, 2. 26 and 14. 90 ppm of commercial material for propargite, respectively. Evaluating the persistence of lethal effects of the acaricides on the bean plants revealed that mite mortality was 100% at 1 day after plant spraying for abamectin which decreased to 55. 62% in 21 days after spraying. While, mite mortality was 81% in 1 day after plant spraying for propargite which decrease to 0% in 21 days after spraying.

In the present study, Integrated and separate application of Trichoderma harzianum i2375 and vermicompost on the control of root-knot nematode Meloidogyne javanica was examined under greenhouse conditions on tomato. Root-knot nematode and fungal isolate identified using morphological characters. In the green house experiment, effects of integrated and separate application of vermicompost and T. harzianum i2375 on tomato plants growth factors and nematode population, in two independent of 90 and 120 days in spring season were tested. Results indicated that integrated application of both the agents not only controlled the target nematode but also enhanced growth parameters of the host plant including fresh weight and length of tomato upper portion which shows the ability of integrated application of these two bio-agents. The number of galls in the application of the integrated treatment was the least and the nematode population in the green-house conditions was up to 78. 6% with the use of integrated Trichoderma and vermicompost, which was significant in comparison with the control at 5% level. Kind of the treatment with reference to the nematode percentage control indicates key role of using of the fungal isolate along with the vermicompost in reducing nematode infection and population indices.

Fusarium wilt of cantaloupe caused by Fusarium oxysporum f. sp. melonis (Fom) is an important disease in the Iran and world. To find resistance source of melon, 18 landraces, collected from different parts if Iran, were evaluated against race 1. 2 of fom in greenhouse experiment in a randomized complete block design with three replication in seed and plant improvement institute The root of seedlings in 1-2 true leaves stage were in 50ml spore suspension of Fusarium oxysporum f. sp. melonis with 106 concentration for 1-2 minute and were returned to trays. Between these landraces, Shadegani as most susceptible landrace and Samsuri as susceptible landrace and Suski as semi resistant landrace and Isablle as resistant landrace were selected for biochemical studies of peroxidase, poly phenol oxidase, catalase, superoxidase and the roots phenolic compounds. Root samples were taken in zero, two, four, six and eight days after inoculation, and used for study of changes enzymes activities and the total phenolic contents. Based on the results obtained, there is a significant difference in the activity of peroxidase, polyphenol oxidase, catalase and superoxide dismutase on different days and the maximum activity was recorded in the fourth and sixth day and the highest and lowest enzyme activity were in Isablle and Shadegani, respectively. Changes phenolic compounds in fourth, sixth and eighth were significant differences each other. Before infection (0 day) the greatest amount of phenolic compounds was recorded in Shadegani (very susceptible landrace), while the spread of disease agent the highest amount obtained on the fourth day after inoculation in Isablle landrace. In this study, the activity of peroxidase, polyphenol oxidase, catalase, superoxide dismutase and phenolics content increased as five factor in the interaction melon landraces with fusarium wilt.

Verticillium wilt is one of the most devastating diseases on cotton. This study aimed to evaluate the effect of three types of composts (derived from municipal waste [MW], crop residues [CR], or animal husbandry silage [AS]) on development of cotton Verticillium wilt under controlled conditions. Experiments were carried out as factorial randomized complete block design with 4 replications. To inoculate Verticillium dahlia, its microsclerotia were mixed in the proportions of 5 and 10 per gram of soil. Each compost type was also mixed, in the proportion of 35% (w/w) with the soil before planting. The data of plant wilting index showed that the composts reduced the disease severity and increased fresh weight of plant foliage. The results indicated that the CR and AS composts caused a significant reduction of wilting. MW compost, however, didn’ t cause significant wilting reduction compared to the control. The fresh weight of plant foliage significantly increased following application of all composts. Number of fungus microsclerotia showed a significant reduction in the soils treated with composts. In vitro studies indicated slowdown of fungi growth in culture media containing extract of the CR compost. Analysis revealed no significant differences between CR and AS composts in reducing index of wilting, and the final number of microsclerotia in the soil and also in increasing of foliage fresh weight of host plant. Based on these findings, two composts of CR and AS are useful to reduce the damage of Verticillium wilt of cotton, as a part of integrated disease management, and necessitate more investigations.

Trichoderma species have a global distribution, representing dominant mycobiota of soils in different regions. Even though Trichoderma species exhibit strong saprophytic potential, they possess significant epiphytic phase and can penetrate internal tissues of plants without causing any harm to host plant. In recent years, substantial attention has been paid on the identification and interaction of endophytic Trichoderma species with plant hosts. However, there is a huge paucity of knowledge on biodiversity of endophytic Trichoderma species in Iran. The present study was aimed to characterize endophytic Trichoderma species from oak trees in Arasbaran forests. For this purpose, during August-September 2014, samples from twig and trunk of oak trees were collected in the Hatam-baig (Meshgin-Shahr) and the Kaleibar regions. A total number of 23 Trichoderma isolates were recovered from sampled areas. Trichoderma isolates were characterized based on morphological data and sequence data of ITS-rDNA region as Trichoderma atroviride, T. citrinoviride, T. harzianum, T. longibrachiatum and T. polysporum. In a phylogeny inferred based on sequence data of ITS-rDNA region, Trichoderma spp were clustered with the representative sequence of the type strain for each of the species with high bootstrap support. All five species are newly recorded from Arasbaran forests and black oak (Quercus macranthera) is reported as new host for these species. With the identification of these species, it will be possible to evaluate their efficacy in control of plant pathogens and promotion of plant growth.

Rhizomania disease is one of the world's most important sugar beet diseases. The disease causal agent is Beet necrotic yellow vein virus. This disease is widespread. In this study, impact of rhizomania on sugar beet yield and qualitative characters consisting of root yield, sugar content, sugar yield, sugar extraction coefficient and amount of non-sugar impurities of root (sodium, potassium, and amino nitrogen) were investigated. For this purpose, 12 monogerm sugar beet cultivars including six commercial cultivars resistant to rhizomania, three tolerant cultivars, and three susceptible cultivars to the disease were planted in a randomized complete block design with three replicate in rhizomania non-infested and infested fields. This study was carried out in two years at Fars Agricultural and Natural Resource Research and Education Center (Zarqan). Results showed that rhizomania reduced the sugar yield by imposing a negative effect on root yield and sugar content. The average decrease in sugar yield in infected treatments, for commercial resistant, tolerant, and susceptible cultivars was 25, 54, and 90%, respectively. Under rhizomania infection conditions, sodium content of all cultivars increased, on average by 165%, but their amino nitrogen content showed an average with 43% reduction. The presence of rhizomania symptoms in resistant cultivars and yield reduction under infection conditions showed that Rz1 gene can not cause the full resistance to the disease.

The melon aphid, Aphis gossypii Glover (Hemiptera: Aphididae), is one of the most important pests causes damage to vegetable both in fields and greenhouses. The biological characteristics related to the efficiency of natural enemies are considered as quality control indices for preliminary screening, prior to release of biological control agents. In this study some biological characters including parasitism rate, emergence rate, and sex ratio of a sexual strain of the parasitoid wasp, Lysiphlebus fabarum (Marshall), was evaluated for individuals that were reared on different stages of A. gossypii. Furthermore, important factors related to offspring fitness (body length, developmental time, fecundity, and longevity) were surveyed. Results revealed that, L. fabarum could successfully parasitize all the nymphal instars of the melon aphid. With the exception of egg size, all other characteristics were significantly affected by host stage. Wasps emerged from the second and third instars had higher fitness than the other stages. Conseuently, L. fabarum may be considered as an effective biological control agent of the melon aphid, although these results need to be confirmed by further field and greenhouse studies.

Cucumber mosaic virus (CMV) is one of the most important infectious plant viruses in Iran. For evaluating infection phenotypes of different isolates 342 samples of cucurbitaceous and tomato plants were collected from different locations in the northwest region of Iran in 2012. After screening by enzyme-linked immune sorbent assay (ELISA), 91 CMV-infected samples were identified. Eight representative CMV isolates whose phylogenetic positions had been determined were selected and compared for their pathological features in zucchini (Cucurbita pepo cv. Ps) plants. According to the determined disease indexes, the isolates were placed in two main groups. Also, evaluation of 2b (viral suppressor of RNA silencing) and CP expression with semi-quantitative RT-PCR showed different concentration of the isolates in test plants. The subgroup IB members from Iran induced more severe symptoms on the inoculated indicator test plants compared to the isolates in subgroup IA. Thus, there seemed to be a correlation between subgroup affiliation and biological properties of the CMV isolates from Iran.

Septoria leaf blotch (STB) disease, caused by Zymoseptoria tritici, is one of the most important diseases of wheat in all over the world and Iran. Genetic resistance is the most important and economical strategy to control this disease. Continuous monitoring of the fungus populations is indispensable to study the efficiency of Stb resistant genes. In this study, virulence pattern of five different isolates on differential cultivars of wheat with resistance genes and the effectiveness of these genes against isolates were studied at seedling stage under greenhouse conditions. The results showed that BK94 and BK56 were the most and the least virulent isolates on differential cultivars, respectively. M3 and Arina were resistant to all isolates. TE9111, Riband and Flame were resistant to three, two and two isolates, respectively. The other differential cultivars were susceptible against the tested isolates. Among the Stb genes, Stb15, Stb16 and Stb17 were the most effective resistance genes to all isolates, therefore they can be used as resistance sources to STB in breeding programs in Iran.

Herbicides are widely used in various fields, but the mechanism of all possible interactions between herbicides and plant have hot been well understood yet. Charcoal rot, caused by Macrophomina phaseolina, is one of the most important diseases of soybean. Imazethapyr, trifluralin and metribuzin herbicides are used as soil-applied herbicides in soybean. Experiment arranged as factorial in Completely Randomised Design (CRD) with 6 replications in a laboratory condition in order to study of zero to 7000 mg. l-1 concentrations of imazethapyr, trifluralin and metribuzin herbicides in Potato Dextrose Agar on medium culture phaseolina mycelium growth rate. Fungus disc was placed on the center of 9 cm petri dishes and mycelium growth was measured daily. Growth rate of mycelium was fitted using four parameters logistics dose-response equation. Results showed that different doses of herbicides have significant effect on fungal growth rate. Trifluralin at 4320 and 5760 ppm, imazethapyr at 2300 and 7000 ppm and metribuzin at 5000 and 7000 ppm concentrations completely ceased the growth of fungus. Imazethapyr showed the most inhibitory effects on M. phaseolina isolates in the PDA medium culture followed by metribuzin and trifluralin.

Feeding of adults of stored-product moths in the genus Ephestia from water and sugar solutions as well as quantity and quality of larval diets would affect many biological properties of adults. In this study, effects of feeding of larvae from dietary glycerol, and male and female adult access to water were evaluated in the Mediterranean flour moth, Ephestia kuehniella Zeller. Larvae were reared on two different diets: wheat germ + brewer’ s yeast + glycerol (10: 1: 2), and wheat germ + brewer’ s yeast (10: 1). Some adults were allowed to drink water for two days before mating and some others had no access to water. Larval feeding from dietary glycerol, if male and female adults had no access to water, had a significant effect on female longevity, but access to water either by one or two sexes made the effect non-significant. Drinking water by the two sexes, depending on feeding of larvae from glycerol-containing or glycerol-free diets, decreased female longevity significantly and non-significantly, respectively. Presence of glycerol in larval diet had a significant effect on longevity of male adults but in contrast with females, access of male adults to water did not compensate the negative effect of glycerol-free diet. Females obtained from larval glycerol diets showed higher fecundity. Drinking water or not by one sex altered the effect of water access on fecundity by other sex. Feeding from dietary glycerol increased the percentage eggs hatched, and mating of males and females with or without access to water showed different effects on egg hatchability. In general, presence of glycerol in larval diet and drinking water by adults increased the adults' longevity and fecundity, and percentage eggs hatched was affected by larval dietary glycerol and male adult access to water.

Wheat streak mosaic virus, a member of the genus Tritimovirus in the family Potyiviridae, is a destructive pathogen of cereals. In this research, NIa-Pro as one of the most important proteinase of WSMV was analyzed. For this purpose, 116 wheat symptomatic samples were collected from North Khorasan, South Khorasan and West Azarbayjan provinces and tested by ELISA. Ten ELISA positive samples were propagated by mechanical inoculation on wheat and were tested by RT-PCR using specific primers that were amplified a 732 bp fragment of full length NIa-Pro coding region in all of the 10 samples. Then, two isolates from Iran, according to their geographical properties, were selected, cloned and sequenced. In the phylogenetic analysis, two distinct groups were separated. The isolates from iran were placed in Group I and subgroup IB close to isolate from America (NC-001886). Iranian isolates formed a sub group separate from previously reported isolates from Iran (Saadat shahr) and Europe. Analysis of cleavage sites in NIa-Pro of the isolates from iran, showed that all of them were conserved in comparison to the isolates previously recorded in GenBank but some substitutions were observed at NIa-Pro motifs. AETT residues at position 121-124 were replaced by GKSH, alanine residue was replaced by Threonin at position 154 and Glutamin alanine at position 208. This research is the first analysis of NIa-pro in isolates of WSMV from Iran.