Applied Entomology and Phytopathology
Year:2010 | Volume:78 | Issue:1 (90)|Papers Count:15

The pistachio fruit hull borer moth, Arimania komaroffi Ragonot (Lepidoptera: Pyrallidae) was first collected from the cultivated pistachio trees, Pistacia vera Linnaeus, of Rafsanjan, southern part of Iran by Samet (Samet, 1985, Entomologist’s gazette, 36: 113- 115). It is known as “Krash” by the pistachio growers in Kerman province, Iran. The population density was remained low until late 1990 decade, however it increased up gradually thereafter. In addition to density, its distribution was also expanded through the recent years. Now, this insect occurs almost in 70% of Rafsanjan’s pistachio plantation areas the main pistachio production region of country, as well as it is causing damage in Sirjan and Zarand pistachio plantations as a patchy localized pest. It is present in the wild pistachio growing areas of Sirjan too. Our field survey showed that at least three parasitoid wasps species attack A. komaroffi, and they are active in pistachio orchards through July to September. The braconid wasp, Iconella myeloenta (Wilkinson) (Braconidae: Hymenoptera), was found as the most common solitary and primary parasitoid of A. komaroffi in Rafsanjan. It develops on A. komaroffi as a larval endoparasitoid. The parasitoid, Habrobracon telengai Muljarskaya (Hymenoptera: Braconidae), was found as a gregarious endoparasitoid for larvae of A. komaroffi. The parasitoid Elasmus sp. (Hym.: Eulophidae) was found as the second dominant parasitoid species for A. komaroffi. This is a gregarious larval ectoparasitoid of A. komaroffi, which attacks the fully developed moth larvae before pupation. In addition, it acts as facultative hyperparasitoid and attacks the braconid wasp I. myeloenta, the primary parasitoid of A. komaroffi, through its cocoon.This is the first record for the activity of above wasps on A. komaroffi. In addition, based on the available references the fist two parasitoid species have not already been reported in Iran. The voucher specimens have been deposited in the following sites; braconid species in the Budapest Museum, Hungary, and eulophid wasp in the State Pedagogical University, Russia.

In order to investigate the resistance of wild oat populations to diclofop-methyl a greenhouse and laboratory experiments were carried out during 2006. The collected wild oat biotypes have already shown several cases of resistance to diclofop-methyl in different locations in Iran. Greenhouse experiments included screening tests and dose response experiments where as, seed bioassay experiment included ID50 determination and dose response experiments. The treatments consisted of wild oat populations included FR1, FR2, FR3, FR4, collected from Fars province, MR1, MR2, MR3, collected from Markazi province, KR1, KR2, KR3, collected from Khuzestan province and S, collected from a location which had never been treated previously with any graminicide. Results indicated that KR1, KR2 and KR3 populations showed resistance to diclofop-methyl according to whole plant and seed bioassay trials. Resistance ratios tested populations were different and ratios that obtained at seed bioassay were lower than those obtained at whole plant assay. It is also concluded that the seed bioassay could be used as a simple, comparatively rapid, inexpensive and accurate method for identifying wild oat populations resistant to Acetyl CoA carboxylase inhibitors.

The aim of the present research was to assess the relative importance of systemic induced resistance in the suppression of Fusarium wilt of tomato by non-pathogenic Fusarium oxysporum (Avr5). Effects of one isolate of nonpathogenic F. oxysporum (Avr5) were tested in vitro and in vivo for their efficacy in controlling Fusarium wilt of tomato. Two methods were applied including root-dip-inoculation and soil’s infestation method with the F. oxysporum f. sp. lycopersici (FOL). Isolate of nonpathogenic F. oxysporum in vitro did not inhibit radial growth of FOL and had no significant effect on reduction growth of pathogen. At the same time in vivo nonpathogenic F. oxysporum (Avr5) with concentration of 0.1 ml conidial suspensions of 106 conidial/ml per gram soil (100 ml conidia per pot) significantly reduced incidence and severity of Fusarium wilt (62% reduction) compared to the control pathogen. F. oxysporum (Avr5) only colonized the epidermis of tomato's root but was not found in vessels of stems, while the FOL colonized inside of root cells and stems of inoculated plants. Plants inoculated with FOL showed disease symptoms after 3 weeks, whereas plants inoculated with F. oxysporum (Avr5) or a mixture of both fungi remained symptomless for 60 days. In order to induce systemic resistance in tomato plant, three bioassays including split-root, benomyl and cutting systems were used. Results of three bioassays indicated that F. oxysporum (Avr5) is able to induce resistance in tomato plants against FOL. Non-pathogenic F. oxysporum (Avr5) remained spatially separated from the pathogen in plants in the split root bioassay, but in the cutting and benomyl systems F. oxysporum (Avr5) and FOL were separated in time, suggesting that these effects were systemic in nature. It has been concluded that application of nonpathogenic F. oxysporum (Avr5) can be considered as a potential biocontrol agent in next studies.

In this research, compatibility of Beauveria bassiana and Lecanicillium muscarium with different concentrations of imidacloprid was investigated. Imidacloprid was employed in three different concentrations, mean concentration (MC), half MC and twice the MC and conidial germination and vegetative growth of both fungi were monitored. The study was conducted in Completely Randomized Design with 6 replications. The results showed that imidacloprid is not compatible with L. muscarium and it caused complete inhibition in fungal vegetative growth in 2MC while the average daily growth rate of B. bassiana was not significantly different from the control using this consentration. Likewise, germination of conidia at 2MC treatment was not affected with imidacloprid while in L. muscarium, rate of germinated conidia were reduced significantly compared with the control. Regarding lack of negative influence of imidacloprid on B. bassiana, combination of these two factors can be recommended in integrated pest management programs.

The Jasmin moth is one of the main pests of nurseries, young olive orchards and also on the suckers of old trees, its biology was studied in the field and laboratory. The female of jasmin moth mates one day after emergence and deposites her eggs in third day individually or in one row on the subsurfaces of leaves. Terminal rows of leaves are prefered for oviposition. The mean of fecundity is 375.125±29 and the most eggs are deposited in early days of oviposition period. This pest has five instars, L1 and L2 are yellowish and the others green. The larval duration stage is 22.28 ± 0.22. The larvae feed on the leaves at the end of the twigs, forming silken webs in which they sheltered and pupated later. The primary stages were feed on the leaves parenchyma and the others on the whole leaves except midribs. The twigs and fruites are attacked as well as leaves during heavy infestation. The mean percent of mortality was nearly %30 during the larval stages. The pupation lasted 7.83±0.112 days and its mortality was nearly %14. The sex ratio (Male: Female) was (1:1.14). The mean longevity of males and females respectively were 14.33±2.4 and 12.59±1.63 days. It produced 8 generations in lab. with mean of 42±0.821 days for each generation and at least four generations in Tarom region environmental conditions. The mean mortality of each generation caused by nonliving agents was: %26.7, %13.4, %50, and % 23.4 respectively. The differences between means of lifespan in various generations were significant in %1 level (P<0. 0001). The fifth generation provided the overwintering stages that mostly were as L3-L5 and pupae.

Fire blight caused by Erwinia amylovora (Burrill) Winslow et al. is one of the most catastrophic bacterial diseases of pome fruits. Among the various host plants, the quince (Cydonia oblonga) tree is one of the most susceptible hosts to the disease. Using the tolerant cultivars is the most economic method for disease control. This research was carried out in order to study the rootstock role on susceptibility of budded quince genotypes to the disease. 13 quince genotypes from central region of Iran, as well as cultivar "Isfahan" as control, were budded on quince and crataegus rootstocks and were evaluated for fire blight resistance in the greenhouse condition by using Ea273, S1 and Z1 isolates of bacteria in spring, 2007. Resistances were evaluated by necrosis progress rate and index of varietal susceptibility (I.V.S) in the shoots. On quince rootstock, the cultivar "Isfahan" and genotype SHA1 with 57.9 and 90.4% final disease progress, showed the lowest and highest symptoms respectively, while on crataegus rootstock, PH2 and NB3 genotypes with 71.5 and 100% final disease progress showed the lowest and highest symptoms, respectively. Results showed crataegus rootstock increased damage severity in 11 genotypes and decreased in other 3, compared with quince rootstock. Effect of rootstock type on the susceptibility changes in KVD3 and NB3 were the highest and in NB4 and PH2 were the lowest. According to the results in most quince genotypes, the crataegus rootstock can not be effective to increase resistance to disease.

The Lesser Kestrel Falco naumanni Fleischer, 1818 (Falconidae) is a migratory raptor in Iran. Using Point Count method, the population of Lesser Kestrels was estimated about 256 individuals in the surveyed areas of Tehran and Golestan provinces in the spring of 2006–2007. The population was consisted of 6 subpopulations namely 12 individuals in Niavaran, 14 around Latian Dam (Tehran), 35 around Kalaleh (Golestan), 70 in Gomishan (Golestan), 50 in Bandar Turkmen (Golestan) and 18 in Khajeh Nafas (Golestan). After nest-finding, a batch of 239 and 118 pellets were collected from roost sites around Latian Dam (Tehran Province) and Bandar Turkmen (Golestan Province) respectively. Each pellet was soaked in 95% alcohol and then teased apart using a pair of forceps and a needle. Animal remains were classified into some categories such as Orthoptera, Coleoptera, Formicidae, Aves and Rodentia. The frequency of each category was calculated. Analysis of the collected pellets revealed that in Latian Orthoptera, Coleoptea and Formicidae were present in 2%, 21% and 9% of the pellets respectively while in Bandar Turkmen they were in 71%, 31% and 4% of pellets respectively. Rodent and shrew remains were present in 18.8% of the Latian pellets of which Meriones sp. (49%) was the most important item followed by field mice Apodemus (21%), Microtus sp. (11%), Soricidae (9%), hamster Calomyscus sp. (4%), and grey hamster Cricetulus migratorius, Mus sp. and Crocidura sp. (each of them 2%). Bandar Turkmen pellets also included Bivalvia and Gastropoda (5%), Mammalia (4%), Aves (3%), Reptilia and Amphibia (3%), Chriroptera (1%) and Dermaptera (1%).

To study of environmental effects on sugar beet traits, population dynamism of Empoasca decipiens and Thrips tabaci, effects of three irrigation regimes (irrigation after 70, 105 and 140 mm cumulative evaporation from class A pan) and three fertilizer levels (200, 150 and 100 kg/ha net nitrogen) were evaluated in a complete randomized block design with 4 replication. The results showed that percentage of water and protein content and dry weight of crop foliage were affected by irrigation regimes and fertilizer treatments and these changes influenced the population of the pests. Irrigation after 70 mm in comparison to 140 mm, increased percentage of the foliage water 78.6%, but its protein content decreased 31.1%. Increase of nitrogen fertilizer from 100 to 200 kg/ha, increased protein content 12.25%. The highest and lowest mean of the pest population were observed in 105 and 140 mm irrigation treatments respectively. Irrigation after 105 mm in comparison to 140 mm, increased population of leafhopper and thrips as much as 3.37 and 3.51 times respectively. Increase of nitrogen fertilizer from 100 to 200 kg/ha, increased population of leafhopper and thrips 37.5% and 48.66% respectively.

Wheat powdery mildew caused by Blumeria graminis f.sp. tritici is one of the most common diseases in cool and humid regions. Awareness of fungal variability is necessary to manage disease specially due to using new lines and cultivars. This study was conducted to detect virulence factors of Blumeria graminis f.sp. tritici using trap nurseries in natural conditions in Gorgan, Mazandaran, Moghan and Varamin regions during 2005-2007. The experiments were carried out using 17 near isogenic lines/cultivars carrying Pm resistance genes received from Germany. The experiments were based on RCBD with three replications in each region. The reaction of the cultivars to B. graminis f.sp. tritici were recorded at booting stage and two weeks later based on scale 0-9. The results of three years study showed that cultivars MARIS HUNTSMAN (Pm2+6), APOLLO (Pm2+4b+8) and RALLE (Pm3d) were highly resistant in all regions and cultivars RONSO(Pm4b), REKTOR(Pm5) and NK-747 (Pm6) were relatively resistant. These cultivars have potential to be incorporated into high yielding commercial wheat cultivars in Iran.

The flight and walking activities of the second, forth, sixth and eighth generations of Trichogramm brassicae reared on Sitotroga cerealella eggs were compared under laboratory condition. The parasitoid wasps were obtained by collecting egg masses of Naranga aenescens from rice fields and Sitotroga cerealella egg traps. The experiments of flight and walking activities was carried out using black P.V.C. tubes and the percentage of inactive, flying and walking wasps to light were calculated. Results showed a reduced flight and walking activities and increased percentage of inactive wasps with the increasing number of generations. In second generation, 41.9±2.88, and 36.7±2.65 of wasps population had flight, and walking ability, respectively, and 21.4±2.45 of them was not able to fly and walking. The highest percentage of inactive wasps were observed at eighth generation, whereas wasps showed significantly better flight and walking activities at second generation. Based on the results, flight and walking abilitiies of T. brassicae were gradually decreased at continuous laboratory rearing.

During a faunistic survey on injurious mites associated with broad leaf trees and ornamental shrubs which was conducted in landscapes of Mashahd in 2008 and 2009, specimens of four species, Eutetranychus africanus (Tuker, 1926), Oligonychus mangiferus (Rahman and Sapra, 1940), Oligonychus yothersi (Mc Gregor 1914) and Schizotetranychus hindustanicus (Hirst, 1924) were identified that are new for Iranian fauna. After preliminary identification, specimens were sent to Dr. Owen Seeman (Queensland museum, Australia).

A survey was conducted to identify parasitoids of wheat aphids in Kermanshah province during 2007-2008. Mummies were collected and reared in the laboratory at 25 ± 1°C, 60-70% RH, and a photoperiod of 16:8 (L: D) hours. In this research, seven species of aphid parasitoids belonging to the family Braconidae, subfamily Aphidiinae were collected from wheat fields of Kermanshah province in spring of 2005-2006, of which Praon gallicum is the first record for the fauna of Iran. This species was collected from bird cherry-oat aphid, Rhopalosiphum padi in wheat fields of Dorud Faraman, Allahyarkhani, Sare Pol and Beshiveh Sare Pol regions of the province at 10- April, 2006, 13- May, 2005, 5- April, 2006, and 5- April, 2006, respectively and were identified by Petr Stary from academy of science of Czech republic. Key to the identification of Praon Holiday species was provided by Stary (1981), (Acta Entomologica Bohemoslovaca 78: 382- 396). P. gallicum was collected on greenbug, Schizaphis graminum in France for the first time and described by Stary (1971), (Annals of Society of Entomology in France 7 (3): 625-627). Pike et al. (1997), (Environmental Entomology 26 (6): 1299-1311) reported this parasitoid on small grain aphids in United States of America and mentioned that it was introduced from Europe. Distinctive morphological characters of P. gallicum with body lenth of 1.2-1.5 mm were as follow: Antennae 15-16 (rarely 17) segmented, F1 five times as long as wide, F2 1/5 shorter than F1, Scape, pedicel, F1 and F2 bright yellow, the rest of antennae brown. Face with a narrow central longitudinal hairless stripe. Forewing m-cu vein absent. Tergite 1 of abdomen quadrate and as long as wide at spiracles and dark brown, base of tergite 2 yellowish. Central lobe of Mesoscutum sparsely pubescent and lateral lobes with large oval hairless areas.