Applied Entomology and Phytopathology
Year:2018 | Volume:86 | Issue:1 (106)|Papers Count:10

The use of plant extracts can consider as an alternative for pesticides, to control post-harvest diseases like apple blue mold. It was efficient method the measuring the enzymes activity involved in plant defense systems to evaluate the disease, but it was expensive method. At present research, the peroxidase activity in treated apple fruits with lavender extracts and pathogen during eight days was investigated. Then, we applied three common models (i. e. multiple linear regression models, neural networks and neuro-fuzzy) to predict the peroxidase activity based on the information of the previous test. The results showed the highest enzyme activity was observed in the infected apples treated with the extract in fifth days, as the days before and it was significant compared to other treatments. The most activity of peroxidase was observed in all treatments except control, was observed on the fifth day. Our constructed models revealed that neuro-fuzzy model had higher performance in the peroxidase activity prediction compared with the other models.

Preliminary studies on nutritional status of 29 commercial Golden Delicious orchards infected to Cytospora canker disease, showed defficiecy of potassium and calcium and excess of nitrogen in most of infected orchard. In this regard, an orchard’ s trials was conducted to determine the effects of balanced potassium, nitrogen and calcium elements on prevention of incidence and development of Cytospora canker disease of 27 years apple Golden Delicious cultivar during 2014-15 in the commercial orchard at Semirom, Iran. Eighteen treatments (nitrogen and potassium at 3 levels and calcium at 2 levels) were designed in a factorial complete randomized block design with three replications. The results showed that deviation from optimum percentage index of nitrogen, potassium and calcium is proper option for predicting the occurrence and development of Cytospora canker disease of apple trees. Deficiency or excess of any nutrient caused imbalances in other elements and influenced the severity of the disease extensivily. The highest percentage area under disease progress curve occurred in most of the treatments, that nitrogen rate was less or more than the optimal amount. Combined application of nitrogen and potassium in most of the treatments significantly reduced the predisposing effects of high nitrogen application. The impact of calcium on reducing disease was lower than nitrogen and potassium. This results of this study showed that, balance utility of nutrients such as nitrogen, potassium in soils of Semirom area orchards and spraying of calcium based on recommended manual reduced Cytospora canker disease at 83. 79 percent.

Tolerance to diseases is, the plant's ability to produce good yield even when the plant is infected by pathogen. In fact tolerant plants are susceptible to the pathogen but not destroyed by pathogens and generally little damage is caused on the plant. In this study, the tolerance of 20 wheat genotypes was evaluated against leaf rust. The effect of leaf rust on yield was evaluated in severe disease (stress) conditions and in protected from disease conditions (the controls) in Ahvaz area. The mean percentage of yield reduction caused by leaf rust was 25. 2% over all genotypes. The range of yield loss was varied from 7 to 46 percent. The lowest yield loss due to the leaf rust, ranged from 6 to 16% in Shirodei, Aflak, Sirvan, Shiraz, Inia and Ofogh cultivars indicating their highest yield stability to leaf rust. Based on these data, the highest yield loss ranged from 30 to 50% in Bolany, Neyshabur, Toos, Alvand, Roshan, Star, Shahriar and Veerynak cultivars with the lowest yield stability. The cultivars Kavir, Shahriar, Roshan, Toos, Veerynak, Bahar, Bolany, Alvand and Ofogh were susceptible to leaf rust. Ofogh and Bahar with 16. 52% and 21. 8% yield loss respectively, were the most tolerant cultivars of this group.

The Long-eared Owl Asio otus (Linnaeus, 1758) (Aves: Strigidae) was previously considered as a rare bird species in Iran but its population has increased in recent years. Raptors, in particular owls regurgitate undigested remains in the form of cylinder called pellet. In this study, 744 pellets were collected from Karaj, Esfahan and Hamedan areas. After collection of pellets and transferring them to the laboratory, they were cleaned, numbered, measured and weighed. Then, these pellets were wetted by alcohol. Pellets were dissected and skulls and other animal remains were extracted, labeled and identified. In total, rodents were present in 551 pellets (74. 06%), birds in 211 pellets (28. 36%), Insectivora in 20 pellets (2. 69%) and insects in 13 pellets (1. 75%). Among 583 rodent prey items identified, 231 items were from the genus Mus (39. 62%), 152 items from Microtus (26. 07%), 133 items from Cricetulus (22. 81%), 47 items from Meriones (8. 06%) but less item numbers were from the genera Rattus, Nesokia and Rhombomys (2. 40%, 0. 69% and 0. 34%, respectively). The dominant prey in Karaj was Microtus (54. 37%), in Hamedan was Mus (43. 80%) and in Esfahan was Cricetulus (35. 15%). Because the Long-eared Owl can inhabit in agricultural ecosystems and near human settlements, it can be recruited to control rodents in agricultural fields.

Root-knot nematodes (Meloidogyne spp. ) are obligate plant parasites distributed worldwide. The genus almost parasitize about 3500 species of different vascular plants. The gram-positive bacteria of the genus Streptomyces have nematicide trait. The effects of millet and grain substrates on the sporulation of Streptomyces carpaticus UTS49, antagonistic ability on Meloidogyne javanica, the growth of tomato seeding and colonization of the rhizosphere were studied. As a result, the antagonists were able to control of root-knot nematode in vitro. Mass production of antagonists conducted with the cheap materials. The result indicated that the best substrate for S. carpaticus was wheat grain. This substrate showed high biocontrol ability against nematode with 71% mortality of the second stage juveniles (J2), reduction of 22/33% of eggs hatching, strong ability of colonization and growth-promotion on tomato. Wheat grain-Streptomyces had a positive effect on shoots and root growth of tomato.

Fig mosaic emaravirus (FMV) is considered as one of the main causal agents of Fig Mosaic Disease complex (FMD). In order to detection and identification of FMV in different regions of Iran and better understanding of the phylogenetic relationships between isolates, a number of 54 symptomatic fig leaves with chlorosis and mosaic symptoms were collected from different fig-growing areas in the center, north and south of Iran. Primary detection for all collected samples performed by DAS-ELISA using polyclonal AP-conjugated antibody which was raised against nucleocapsid protein of FMV positive samples in DAS-ELISA were checked by RT-PCR using NP gene specific primers. The amplified fragments of 14 isolates were cloned and sequenced. DAS-ELISA results indicated to a 55. 5%FMV infection of collected isolates. Phylogenetic analysis on the basis of nucleotide sequences categorized the isolates in two main groups in which isolates from the center and northern regions of Iran placed in a separate subgroup beside other isolates from other countries which their complete coding sequences were available in GenBank of NCBI whereas the isolates from south of Fars province (Estahban and Jahrum districts) clustered in a separate phylogenetic group distinct from other Iranian and the world isolates which may show that genetic makeup of FMV may be affected by geographical isolation. A significant correlation between symptoms severity and phylogenetic groups observed that may put forward the probability of having a new viral strains in Fars province.

Yellowing is one of the most prevalent symptoms in chickpea fields, worldwide and Iran. Faba bean necrotic yellows virus (FBNYV, genus Nanovirus, family Nanoviridae) is associated with the yellowing symptoms in the chickpea fields. During the survey of the Lorestan and Kermanshah provinces in May 2015-2016, chickpea plants showing yellowing symptoms were collected and total DNAs were extracted. The samples were checked for nanovirus infection by PCR, using nanovirus-specific degenerate primers. Total DNA preparations from the nanovirus-positive samples were used for RCA, using
29 polymerase and restriction endonuclease Aat II digests yielding products of ~1kb corresponding to linearized nanovirus DNA components. FBNYV genomic components were amplified using RCA products and specific primers of eight different U1, M, N, C, S, R, U2, and U4 components. The amplified fragments were purified and sequenced. Nucleotide sequences of the eight different components of three Iranian isolates of FBNYV (Lor-28, Lor-1, and Ker-21) were compared with FBNYV sequences in GenBank. Sequence comparison indicated that Iranian isolates of FBNYV are most similar to Azerbaijan isolates of FBNYV: FBNYV-[AZ; 12], and FBNYV-[AZ; 13. 5]. Phylogenetic analyses of nucleotide and deduced amino acid sequences of DNA-S, C, and U1 revealed that Iranian FBNYV isolates clustered with Azerbaijan isolate FBNYV-[AZ; 12 ](group II), while DNA-R, DNA-M, DNA-N, DNA-U2, and DNA-U4 clustered with FBNYV-[AZ; 13. 5], (group I). Considering the genomic differences between two Azerbaijan isolates, which can be expected among Iranian isolates. These results may provide evidence of the reassortment occurrence among Iranian and Azerbaijan FBNYV isolates.

Foraging natural enemies rely on semiochemicals from a plant-host complex for recognition and acceptance of host, thus, key compounds that mediate behavioral response of parasitoids must be identified. We studied the choice time and olfactory responses of Habrobracon hebetor (Hymenoptera: Braconidae) females to the host odors, the Carob moth Ectomyelois ceratoniae, pomegranate fruit and extracted hexane associated with them performed by passing a stream of air in a Y-shaped olfactomete. The treatments were last instar larvae of carob moth, its faeces, infested pomegranate and pomegranate with mechanical damages. The results showed that H. hebetor preferred carob moth larvae and its faeces. There was significant difference of parasitoids choice time between pomegranate with mechanical damages and other treatment. The results of extracted hexane odor indicated that, the odors spread from the larvae, its faeces and infectrd pomegranate exhibited significant differences in wasp attraction, comparewith the clean air. Based on the results and complementary information on detection of the effective attractants of the parasitoid wasps, the efficacy of the wasp can be increased in the field.

In this study, the nanoemulsion containing Mentha longifolia essential oil was produced by using high-pressure homogenization method and its fumigant toxicity was compared with ordinary M. longifolia essential oil on different stages of Ephestia kuehniella. Experimental conditions were as follows; 27± 1 ° C, 70± 5% relative humidity in total darkness. Concentrations of 111. 1-1111. 1 and 62. 9-92. 6 μ l/l air of oil have been used to control larva and eggs, respectively. Nanoemulsion concentrations were studied at 122. 2-1111. 1 μ l/l air for larvicide experiment and 81. 4-114. 8 μ l/l air for ovicidal stage. PT50 value at 1111. 1 μ l/l air as a larvicide for nanoemulsion and oil was estimated about 15. 18 and 3. 69 days, respectively. This value, at 92. 6 μ l/l air on egg was 14. 44 and 2. 58 days, respectively. The relative median potency parameter (RMP) showed that there was significant difference between PT50 values of essential oil and its nanoemulsion on both of the two stages of pest. Results showed that nanoemulsion containing M. longifolia oil can release slow properties lead to durability of fumigant toxicity of oil in the long term. Therefore, this new formulation could be considered as a new and ecofriendly biopesticide in pest control.

One of the major damage of sunn pest, Eurygaster integriceps, is its destructive effects on the quality of wheat grains, which is known as sunn pest kernel damaged. Nymphs and adult of the bugs inject salivary glands enzymes by piercing-sucking mouthparts into the grains, which degrade glutens, reduce dough and bread wheat quality. Grain damage percentage is calculated by the both numerical and weighing methods. In this research, an experiment was conducted to compare the relationship between these two methods. We measured 225 damaged wheat grain samples delivered from Arak (n = 30 × 3), Ghazvin (n = 20× 3) and Lorestan (n = 25× 3). A digital scale with 0. 1 mg precision was used to weigh kernels. For these samples, the number and weight of damaged and undamaged grains were recorded. In general, undamaged kernels with an average weight of 34 mg were heavier than damaged ones with average weight of 30 mg. Although, there was a significant difference between the numerical and the weight values, a significant positive correlation (r = 0. 98; P <0. 0001) was detected between the two methods. By using the equation y = 0. 8374x + 0. 02, where x and y are the numerical and weight values, respectively, we are able to convert values from a given method to another one. However, the weighing method is advantageous in terms of simplicity and speed.