نشریه آفات و بیماریهای گیاهی
سال هفتاد و نهم شماره 1 (پیاپی 92، شهریور 1390)

Russian wheat aphid, Diuraphis noxia (Mordvilko), is a serious pest of cultivated barley, Hordeum vulgare L., in many parts of Iran. A greenhouse study was conducted to identify resistance of 76 barley genotypes along with oat, Avena sativa, as a resistant check. Test was arranged in complete randomized designs with four replicates. Plants were infested by different stages of D. noxia in first leaf stage. Twenty one days after infestation, resistance indices including: damage rating, stunting, percentage of leaf rolling and growth of infested plants in compared with control plants were estimated. We did not find highly resistant or highly susceptible genotypes in this study. On the base of three traits (damage rating, stunting, percentage of leaf rolling) genotypes and varieties: Desnod-navaro, Lokht, Makoei, B6, U.N.K, 74B4-4709, 74B4–4720, 74B4–4807, M73urbyt-1, 74B4–4814, M73urbyt-6 and M73 urbyt -14 were resistant, whereas other genotypes classified from moderate to highly susceptible.

One of the important physiological disorders in apple cultivars is “Braeburn Browning Disorder” (BBD) observed as brown spot associated with cavities in fruit pericarp and thus is distincted from other kind of disorders in fruit endocarp. BBD disorder is more occurred in storing time. However, the symptom of the disorder was observed in growth orchard conditions during three test years. This research is conducted in order to determine the best harvest time and consideration of relation incidence of disorder with it. Additionally, the harvest mature parameters including the number of days since full flowering till harvest time, cumulative growth degree day (CGDD), flesh firmness (FF), starch scale (SS), the percent of total soluble solid materials (sugar) (TSS), titratable acidity (TA), weight less (WL) and pH were measured. The results showed that the best harvest time was variable between 154-166 days from full flowering to harvest time during the experimental years (2004-2006) in Mashhad. In the optimum time for harvesting the average of TSS was 15.95%, TA 0.69%, SS 3-3.8%, pH=3.43 and FF 8.49 Kg/N for average of fruit weight 206 gr resulted in lower incidence of disorder during storage. Also, weight less was at the least amount, 18.14 Kg/ton. The total CGDD showed an increase trend 1819-1983 DD. In other word, the more average DD during the specific time for fruit maturity caused the less incidence of BBD and there was a negative correlation between CGDD and Braeburn Browning Disorder incidence.

The olive fruit fly, Bactrocera oleae Gmelin was listed as a quarantine pest in Iran since its resurgence in many parts of the world. Now it is considered the most important pest on olive in Iran. The nature and rapid distribution of the pest prioritized the emergency control measures in order to slash down the ever-increasing crop loss in infested areas. Therefore a study was conducted to compare the conventional method of liquid chemical spray with the bait spray technique during 2005-07. The study was conducted through a RCBD design including 4 treatments as: 1- Hydrolized protein (%3) mixed with 0.001 concentration of deltamethrin (EC 2.5%), 2- Hydrolized protein (%3) mixed with 0.002 concentration of dimethoate (EC 40%), 3- 0.002 concentration of spinosad (GF-120) and 4- Control (no treatment). Each treatment was replicated 4 times. In the second year of the experiments two more treatments were also added in studies including: Hydrolized protein (%3) mixed with 0.001 concentration of malathion (EC %57) and 20% concentration of Assa fetida extract.The results revealed significant differences among treatments. Based on the comparative analysis and considering the environmental hazards of chemical control, it could be recommended that the application of the hydrolyzed protein (%3) mixed with 0.001 concentration of deltamethrin (EC 2.5%) on about 1-2 m2 foliage canopy areas in South West direction of every other tree would control economically and efficiently the olive fruit fly. However, the spinosad could be a more rational alternative when the pest would occur in low densities (about 3-5 adult flies captured by MacPhail traps for 5 days).

Hamedan province is one of the main potato growing areas in Iran. Potaoto scab disease caused by Streptomyces spp. is one of the prevalent and important diseases of potato in this provice. Potato tubers with symptoms of scab diseases including raised and deep or shallow pitted lesion were collected from potato growing area in this region. A total of 20 and 25 strains of Streptomyces were isolated from raised and pitted lesions on potato tubers respectively. The pathogenicity of these strains was confirmed on potato mini tubers and mature plants under greenhouse condition. Different isolated scab inducing Streptomyces strains showed diverse of symptoms on potato tubers. Protein electrophoretic profiles of the Streptomyces indicated diversity among the isolated strains. Colony color of the isolated Streptomyces strains on YMEA medium was grey and white-grey and they formed spiral or flexous spore chain on their aerial mycelium five to 10 days after cultivation. All selected strains were belonged to the Streptomyces genus and most of them used D-fructose, manitol, D-glucose, raffinose, rhamnose, sucrose, D-xylose, meso-inusitol and arabinose as a sole source of carbon. Phenotypic characteristics of the tested strains showed that they were belong to Streptomyces and includs three groups. First group of the strains produced melanin pigment from tyrosine and they were identified as S. scabies. Strains of the second and third groups were identified as S. acidiscabies, and Streptomyces sp. respectively. Untill now three phytotoxins including thaxtomine (the main pathogenicity factor), concanamycine and FD-891 compound were reported as pathogenicity factor of the Streptomyces strains inducing potato scab disease all over the world. All of these phytotoxins induce raised, russeted or neted lesion on potato tubers. Phytotoxins were extracted from culture filterate of the tested Streptomyces strains grown in oatmeal broth using aseton. The extracted phytotoxins were concentrated by rotary evaporator and were subjected to thin layer chromatography (TLC). Results showed that only raised, russeted or neted lesion inducing strains including S. scabies EF-35 produced thaxtomin. Potato pitted inducing Streptomyces strains did not produced thaxtomin or concanamycin as pathogenicity factors however they produced an unknown compound which maybe a new pathogenicity factor. Characterization of this new pathogenicity factor is very important for management of the disease in the future.

The predatory bug, Anthocoris minki pistaciae was known as a natural enemy of the common pistachio psylla, Agonoscena pistaciae in pistachio orchards in Kerman province. The prey consumption and fecundity of this predatory bug were determined at constant temperatures, 50-60% R.H. and 16:8 L: D hours using psyllid nymphs as prey. Based on the results, prey consumption was increased up with increasing of temperature significantly. The daily prey consumptions at nymphal stage were increased from 13.6 at 17.5 C to 21.3 at 30 C on average. The adult’s prey consumption at two temperatures of 27.5 C and 30 C were 41.76 and 50.87, respectively and the differences were significant. The effect of five different prey densities e.g. 10, 15, 25, 50 and 75 fourth instars’ psyllid nymphs were examined on predator’s fecundity for 7 consecutive days. The results showed that this predator laid 4.5, 6.7, 9.9, 10.6 and 11.1 eggs per day respectively. This study revealed that the nymphs of A. pistaciae are a suitable prey for A. minki pistaciae for development and reproduction. In addition, this predatory bug has ability to keep its population under a harsh condition, like when the prey density is in low level.

The cuckoo wasps (Hymenoptera, Chrysididae) having interesting metallic coloration are interesting family of wasps that are not studied sufficiently in Iran. This family is reviewed in Iran, based on recently collected materials from north- west of Iran and available literature. Thirty species are listed from the subfamily Chrysidinae of which, 25 species are recorded for the first time from Iran. In addition, keys to Iranian genera and discussions of these species are given. Found species in this research were listed: Chrysis angustifrons Abeille, 1878; Chrysis annulata Buysson, 1887; Chrysis comta Förster, 1853; Chrysis concolor Mocsáry, 1892; Chrysis fulgida Linnaeus, 1761; Chrysis gracillima Förster, 1853; Chrysis grohmanni boloivari Dahlbom, 1854; Chrysis kokandica Radoszkowski, 1877; Chrysis leachii Shuckard, 1836; Chrysis marginata Mocsary, 1889; Chrysis pulchella Spinola, 1808; Chrysis pyrrhina Dahlbom, 1845; Chrysis rubricate Mocsary, 1902; Chrysis soror Dahlbom, 1854; Chrysis near subanalis Linsenmaier, 1968; Chrysis taczanovski Radoszkowski, 1876; Chrysis viridissima Klug, 1845; Spinolia dournovi (Radoszkoowski, 1866); Spintharina vagans Radoszkowski, 1887; Trichrysis cyanea (Linnaeus, 1758); Hedychridium dzhanelidzei Semenov, 1967; Hedychrum flavipes temperatum Linsenmaier 1959; Holopyga punctatissima Dahlbom, 1854; Omalus biaccinctus (Buysson, 1893); 1854; Peudomalus bergi (Semenov, 1932).

Binomial sampling plans was developed for monitoring Metopolophium dirhodum population in wheat fields of Varamin region, Iran. Aphid population was sampled weekly during two growing seasons of 2001-2002. In each sampling date, 50 wheat stems were chosen randomly and the number of aphids was counted and the data was used for developing binomial sampling plan. The results indicated that the sample size estimated from the binomial method was larger than the enumerative method at the density lower than one aphid per tiller. However, a larger sample size was required in enumerative method at higher aphid densities. Analysis of the linear regression between the observed and estimated proportions of wheat tillers infested with M. dirhodum showed good fit between the binomial model and the data. Applying the model, it was possible to estimate the mean aphid population densities observed in this study (0.02-20.18 aphid/tiller). The results revealed that the developed binomial sampling plan at precision levels of D= 0.25 (acceptable precision level in IPM) could be applied to reduce sampling time in monitoring programs of M. dirhodum in irrigated wheat fields of Varamin region.

Dried fruit moth (Cadra cautella) (Walker) is one of the most important pests of dried fruits and was reported on dried date, dried fig and raisin from Iran. The biology of this pest has not been studied on dried fruits products of Iran, regardless of economic value of this pest. In this research some biological characteristics including development time, fecundity and survivorship of C. cautella on dried fig, dried berry, dried date and raisin were investigated. All experiments carried out at constant temperature room (29±1 °C, 60 ± 5% RH and Photoperiod 16L: 8D). Based on the results, the highest (251.38±16.51) and lowest (177.83±15.25) fecundity occurred on the dried fig and raisin respectively. Shortest and longest development time from egg to adults for female was occurred on dried fig and raisin respectively. Also, the highest (91.52±3.16%) and lowest (83.23±2.83%) survivorship of immature development stages of C. cautella were observed on dried date (Zahedi variety) and raisin respectively. Thus dried fig and dried date (Zahedi variety) are preferred by C. cautella.