Journal of Applied Research in Plant Protection
Year:2019 | Volume:8 | Issue:3|Papers Count:8

Pomegranate aphid, Aphis punicae (Hom., Aphididae) is one of the most important pests of pomegranate in Iran. In this study, seasonal population dynamics of this aphid was studied in Sirvan city, Ilam province. For this purpose, sampling was performed bi-weekly in an experimental orchard, 1 hectare area, during two years (2016-2017). Also, Taylor power law and Iwao's patchiness were used to determine spatial distribution of the pest on pomegranate shrub. Green's model was used to develop a fixed-precision sequential sampling plan of the pest on pomegranate shrub. Results showed that pomegranate aphid has one generation and the pest occurred during spring (May to June) on pomegranate shrub in Sirvan city. Population peak of the aphid was observed in end of May. Spatial distribution of the pest was aggregative. Optimum sample sizes varied from 375-488 and 135-175 shoots according to the pest density at precision levels of 0. 1 and 0. 25, respectively.

In order to evaluate the effect of Fusarium verticillioides on seed yield, catalase (CAT) activity on polyacrylamide gel and quantum yield of maize line, a factorial experiment based on randomized complete block design with five replications during 2017 growing season at the Payame Noor University, Mamaghan branch was performed. The experimental factors were two maize lines (B73 and MO17) and two levels of F. verticillioides (control and fusarium contamination). The results indicated that Fusarium verticillioides reduced seed yield, but enhanced CAT acivity in two maize lines. Further more, minimum fluorescence (Fo) in MO17 decreased, and increased in B73. Water splitting complex at donor side of PSII (FV/Fo) in B73 was increased, but was decreased in MO17. The level of maximum fluorescence (FM) in both line decreased. The energy necessary for closing reaction centers in PSII (Sm) and number of the QA reduction during fluorescence from Fo until FM (N) in MO17 were increased, but were decreased in B73. The results of this study revealed++ using from the chlorophyll a fluorescence can be a rapid and non-destructive method for evaluation of the maize reactions to injures caused by fusarium fungi infections.

Elm is one of the most important ornamental trees and is used extensively in design of urban green space. Dieback and canker disease of elm has been widespread in Tabriz green space and other cities in province in recent years. In order to identify the factors involved in dieback and canker of elm trees in Tabriz city, symptomatic and healthy samples were taken and 208 fungal isolates from 64 plant samples were purified. Identification of species was carried out using morphological and sequence data of the ITS or TEF regions for some species. In this study, 16 species of fungi including, Ophiostoma novo-ulmi, Fusarium solani, F. proliferatum, F. tricinctum, Pestalotiopsis brassicae, Cytospora rhodophila, C. chrysosperma, Didymella glomerata, Chaetomium globosum, Ch. rectanguare, Clonostachys rosea, Seimatosporium lichenicola, Coniolariella macrothecia, Pleurostomophora ochracea, Sordaria sp. and Geosmithia sp were isolated from sapwood and wood parts of trunk and main branches with vascular discoloration and healthy trees. Among the identified isolates, Fusarium and Chaetomium were the most abundant taxa. Chaetomium globosum, Ch. rectangulare, F. proliferatum, S. lichenicola, P. brassicae, Co. macrothecia, Pl. ochracea, C. rhodophila, Geosmithia sp., Cl. rosea and D. glomerata are new reports on elm host worldwide.

Population density and spatial distribution pattern of Tetraneura ulmi (L. ) (Hemiptera: Pemphigidae) galls on elm, Ulmus densa Litv. were determined in Miandoab, West Azerbaijan during 2015-2016. 20 samples from every four cardinal directions in lower one third part of crown were randomly selected from each tree per sampling dates. One leaf was selected as a sampling unit. One data set including 200 leaves collected from 10 trees. Results showed that population density of aphid galls in the south of tree, was significantly higher than other directions. The spatial distribution pattern of aphid galls using Taylor's method, index of dispersion and Lloyd's mean crowding was regular. Moreover, there was no significant relationship using linear regression between the temperature and relative humidity with the number of galls. Correlation between length and width of galls with number of aphids was calculated. There was significant positive correlation between number of aphids and the length / width of galls.

In this study, the efficiency of different traps including window trap and colored pan traps (white, yellow, red, purple and blue ones) to capture members of the order Coleoptera was assessed in the two rangeland and farmland habitats of the Saral Agricultural Station of Kordestan province. During the study, a total of 18509 individuals from 19 families of the Coleoptera were collected using the different traps. The results showed that the rarefaction curve of window trap had the most coordination and estimation with total rarefaction curve. There was significant difference (α =5%) among the traps in value of Shannon-Wiener index (P=0, df=5, F=37. 07) and Simpson index (P=0, df=5, F=10. 87) in rangeland area. While window trap had higher mean Shannon-Wiener and Simpson indexes (0. 9± 0. 06 Bit and 5. 8± 1. 1 respectively) than colored pan traps. In farmland area, there also was significant difference (α =5%) among the traps in value of Shannon-Wiener (P=0, df=5, F=16. 84) and Simpson indexes (P=0, df=5, F=9. 18) in, while window trap and white pan traps had highest mean Shannon-Wiener index (0. 9± 0. 02 Bit and 0. 8± 0. 08 Bit respectively) and Simpson index (6. 1± 0. 5 and 5. 6± 1. 5 respectively).

Egg parasitoids are the most important natural enemies of Sunn pest, Eurygaster integriceps Puton (Hem.: Scutelleridae), which play important role in the control of this pest. Among its parasitoids, Trissolcus grandis (Thomson) (Hymenoptera: Platygastridae) is the most widely distributed and prevalent species, which used in this research, to determine the effect of light intensity and photoperiod on life history and population growth parameters. At the first part of this study, effect of three light intensities, (5331, 1412. 5 and 706 Lux) was studied at 26 ± 1˚ C, 50± 10% RH and 16: 8 (L: D) photoperiod. Significant differences were observed in all stable population growth parameters except net reproductive rate (R0). Total fecundity also showed significant differences among the light intensity treatments. Moreover, effect of four photoperiod regimes, 10: 14, darkness, 12: 12 and 14: 10 h (light: darkness) were studied at constant laboratory conditions. Significant differences were observed among all parameters as they were classified within two groups (10: 14 and darkness in a group compared to 12: 12 and 14: 10 h in the other one). Significant differences were also observed among the treatments of the other parameters including developmental time, total fecundity and sex ratio. Overall, light intensity and photoperiod had limited although significant effects on the most biostatistics of T. grandis. It seems that T. grandis is able to successfully develop, survive and reproduce under a wide range of light regimes.

Stripe (yellow) rust caused by Puccinia striiformis f. sp. tritici, is one of the most devastating disease of bread wheat (Triticum aestivum) in the world. This rust disease represents a constant threat to wheat production in several countries in Central and Western Asia (CWA). A wide range of virulent yellow rust pathotypes is evolving in this region causing the breakdown of widely utilized sources of resistance in wheat. Hence, the knowledge of effective resistance genes in the region will enable breeders to target those useful genes in their breeding programs. In order to determine of effective resistance genes in Ardabil, northwest of Iran, virulence patterns of wheat yellow rust were studied from 2015 to 2016 under the field conditions by planting of differential sets and isogenic lines. Seedling reaction was also evaluated under field conditions in 2010. Results showed that yellow rust resistance genes Yr3V, Yr3a, Yr4a, Yr4, Yr5, Yr10, Yr15, Yr16, YrCV, YrSD, YrND were effective and the race-nonspecific resistance genes YrA3, YrA4, Yr18 and Yr29 and genes in cultivars; Parula and Pavon 76 were partial effective during the study period. Virulence was observed for genotypes having resistance genes Yr2, Yr6, Yr7, Yr9, Yr17, Yr20, Yr21, Yr22, Yr23, Yr24, Yr25, Yr26, Yr27, YrSU, and YrA, and therefore, they were ineffective. Cluster analysis of genotypes based on the seedling and adult plant reactions, showed considerable diversity among the wheat cultivars/lines studied. The Genes found effective against yellow rust under natural conditions may be deployed singly or in combinations with durable resistance genes to develop high yield resistant wheat cultivars in wheat growing areas that yellow rust races have the same virulence pattern to the prevalent race/s of Ardabil.

Hamedan is one of the pioneer provinces of Iran in the cultivation of green-house grown crops, especially cucumber. Frequent pesticide applications to control the pests in greenhouses have raised public anxiety concerning the pesticide residue in green-house products. The present report is the results of an investigation done on pesticide residue levels in green-house grown cucumber in Hamedan province. In this study 39 cucumber samples were collected from green-houses across the province. The residue levels of nine pesticides (dichlorvos, malathion, diazinon, pirimicarb, chlorpyrifos, imidacloprid, bromopropylate, tetradifon and metalaxyl) in each sample were determined, using Gas Chromatography-Mass Spectrometry (GC-MS) or High Performance Liquid Chromatography (HPLC) analytical methods. The results indicated that no sample was completely free of residues of all tested pesticides. In 37. 5% of the samples, the pesticide residue levels were higher than the maximum residue levels (MRLs). The residues of bromopropylate, tetradifon and pirimicarb were not higher than the MRLs in any sample. The average residues of diazinon, chlorpyrifos, dichlorvos and malathion in the samples were higher than their corresponding MRLs. The ratios of the mean residue to MRL (mean/MRL) for these four pesticides were 9. 54, 4. 84, 3. 74 and 1. 93, respectively. This is the first report on pesticide residue levels in green-house grown cucumber in Hamedan province.