PLANT PROTECTION JOURNAL
Year:2011 | Volume:2 | Issue:4 (8)|Papers Count:12

In order to find alternatives for conventional pesticides, the fumigant toxicity and ovipositional deterrency of essential oils of summer savory, pennyroyal mint, ostokhodus and rosemary were tested against adults of cowpea beetle Callosobruchus maculatesF. (Col.: Bruchidae). The experiment was conducted using a completely randomized design with six concentrations and five replications. Experiment was carried out at 30±2oC and 60±5% R. H. under dark condition. Concentration of 560 ml/lair essential oils of summer savory, pennyroyal mint, ostokhodus and rosemary caused 95.78, 87.78, 57.33 and 65.11% mortality of adults, respectively. LC50 values of essential oils of summer savory, pennyroyal mint, ostokhodus and rosemary were found to be 69, 106, 322 and 205 ml/l on adults, respectively. Essential oils of all tested plants, showed significant reduction of ovipositional rate of cowpea beetle. The highest concentration (190 ml/lair) of essential oils of summer savory, pennyroyal mint, ostokhodus and rosemary caused 83.22, 92.45, 62.34 and 73.24% ovipositional deterrency, respectively. Essential oils of summer savory and pennyroyal mint showed the highest control on cowpea beetele. Therefore they could be recommended as safe pesticides for control of storage pests.

In a 3-year investigation on french bean fields, samples with mosaic, mottling and yellowing symptoms were collected from French bean fields in various regions of Isfahan province. The symptoms resulted from inoculating samples to test plants and serological tests, indicated that the samples infected to Bean common mosaic virus(BCMV), Cucumber mosaic virus (CMV), Alfalfa mosaic virus(AMV) and Beet curly top virus (BCTV). Frequency of the viruses was determined through sample collecting from 2-8 leaf till flowering stages it was indicated that 121BCMV was the prevalent virus in all French bean fields.Infection rate to BCMV in 2-4 leaf stage was 0.41-2.31% and in flowering stage was 3.7-23.16%. Infection of bean fields to CMV and AMV in 2-4 leaf stage were 0 and 0.17% and in flowering stage were 2.74 and 8.92%, respectively. In seed transmission test, 1.34% and 0.02% were infected to BCMV CMV respectively, and infection to AMV was not observed in the seedlings emerged from fied collected bean seeds.

During 2006-2009 canker symptom and blast in pear (Pyrus communis) and apple (Malus communis) trees were observed in several orchards. The symptoms partly resembled to fire blight disease caused by Erwinia amylovora, except for the absence of gum exudation the affected tissues. A gram-negative, rod-shaped and aerobic bacterium was consistently isolated from affected tissues. All colonies produced levan on SNA (Sucrose nutrient Agar). Fluorescent pigment was produced on King, s B medium. Strains were catalase positive, oxidase and arginine dihydrolase negaative and did not rot potato tuber slices. They showed negative reaction for starch and esculin hydrolysis, production of acetoin, indole and H2S. Six strains produced syringomycin and a hypersensitive reaction in tobacco and geranium. Froctuse, glucose, galactose, sucrose, mannose, mannitol, glycerol, citrate, fumarate, succinate and lactate used as carbon sources. No strain utilized maltose, inulin, starch, dextrin, oxalate, formate or benzoate. Based on these and additional characteristics, the strains were identified aspseudomonas syringaepv syringae. Pathogenicity tests on twings and seedlings of a local cultivar of pear was performed by two strains. This is the first report of apple blast occurence in Iran.

Beauveria bassiana (Balsamo) is an entomopathogenic fungus one of Oryzaephilus surinamensisL.. In this study effects of sublethal doses of pathogen on reproductive potential, the amount of oviposition and the percentage of egg hatching of sawtooth beetles were investigated in terms of feeding on three Dates cultivars including Sayer, Zahedi and Deiri long in vitro condition. Adults were treated by 5 sublethal doses including 102, 5×102, 103, 5×103 and 104 Spores in ml and compared by control. Then, the sublethal doses of reduced reproductive potential of each cultivar were calculated by using Log-Probit analysis method.The tested doses of pathogen had decreasing effects on fertility index. The synergist of fungal pathogen and cultivars on reduce fertility rates were gradually by the increasing pathogen doses. Minimum and maximum sublethal doses for reducing the 50 percent amount of oviposition were showed in population grew on Zahedi and Deiri cultivars and equivalent to 1.497×103 and 4.963×103 spores/ml respectively. Minimum and maximum sulethal doses for reduction 50 percent egg hatching were showed in population grew on the Zahedi and Sayer cultivars and, equivalent to 6.316×103 and 8.28×103 spores/ml respectively. The results of this study showed that the fungus B. bassiana had a significant effect in reducing the reproduction potentials. The pathogen ability to reduce the reproduction potentials was in addition depended on the fungi dose and Date cultivars that feeding by the pest.

Early blight is an important and ubiquitous disease which attacks many herbaceous plants Specially Solanaceae family. Already this disease threaten the potato fields In Iran. The experiments were conducted in order to study the effects of rovral, Chlrotalonil, Mancozeb fungicides in 1 ppm against flint in 1, 2, 5, 10 ppm on different culture media, including PDA and CMA for two species Alternaria alternata & Alternaria solani. The result indicated that, all of tested fungicides could prevent the growth of two species with the various levels, as far as the growth rates are concerned. Also flint fungicide in various concentrations, 1, 2, 5, 10, 20, 50, 100, 200, 500 and 1000 ppm indicated that it could effectively inhibit the growth of two fungal species, as the dosages are increased, indicating the reductions in the growth correspondingly. The highest inhibitions were flint 500 and 1000 ppm and the lowest in flint 1 ppm. This fungicides had a very significant effects on the sporulation of A. alternate, indicated that, with the increased in fungicides concentrations, the sporogenesis decreased, in which the highest sporulation was in Mancozeb treatment and the lowest was in flint with 1000 ppm Also, the results indicated, that the fungicides had effective reductions on the dry and wet mycelial growth weights on zapeks culture media, where the highest wet weights were observed in Mancozeb fungicide, and the lowest was in flint, 1000 ppm.

In recent years, plane trees showed a highly infestation to a species of clearwing moth in Isfahan. Studies on determination of the species indicated that this serious new pest was Synanthedon caucasica Gorbunov (Lepidoptera, Sesiidae). The observed plane trees were highly (95.7%) infested to the moth. The mean estimated damage index in different areas of Isfahan varied between 3.3 and 7.4, with an overall mean of 5.5.

Species of Orius Wolff are widely recognized as predators of small insects such as aphids and thrips, insect eggs, hemipteran nymphs and mites. During 2010- 2011 faunistic studies were carried out according to the recognition of anthocorid bugs in Iran, some species were collected and identified, of which Orius maxidentexGhauri is newly reported from Iran. This species was collected from the Hormozgan province (Bandargah and Ziaratali regions).

To study the role of Pythium species as the turf pathogenic agents, during the years 2005 and 2006, diseased samples and soil samples from green spaces and sport fields were collected from different regions of Tehran province. From isolates identified, Pythium catenulatum Matthews has been reported from turfgrasses in other countries, but our study is the first report of this species in Iran. Pythium okanoganense Lipps has been isolated from soil in Iran but hasn’t been recorded from turfgrasses in Iran and other countries yet.

In 2010, during a Research on leaf-feeders of common fig (Ficus carica L.) in Kerman, a new pest was found and identitied as Phycodes radiate (Ochsenheimer, 1808) (Lep.: Brachodidae). The larva feed from upper epidermis and parenchyma tissue of leaves and cause the folding of the leaves by web formation. This is a first report of this species from Iran.

Mixed infections of cucurbits by Cucumber green mottle mosaic virus (CGMMV) and Watermelon mosaic virus (WMV) exhibit a synergistic interaction. Watermelon, cucumber and cantaloupe co-infected by the WMV and CGMMV displayed synergistic pathological responses, finally in some cases, progressing to vascular wilt and plant death. Accumulation of CGMMV RNAs in a mixed infection with WMV in some cucurbits was higher than infection with CGMMV alone. Moreover, the level of capsid protein from CGMMV increased in mixed infection. However, the level of WMV did not show any significantly increase in doubly versus singly infected plants. Single infections of WMV or CGMMV on the same hosts produced only vein clearing, blistering, systemic mosaic or mottling on the upper leaves and similar symptoms developed after double infection. It is concluded that co-infections with WMV and CGMMV displayed synergistic interaction which could have epidemiological consequence.