فصلنامه گیاه پزشکی
سال سی و پنجم شماره 4 (زمستان 1391)

In this study، the effect of salicylic acid (SA) on root knot nematode (Meloidogyne javanica) pathogenicity and induction of some defense mechanisms such as polyphenol oxidase enzyme activity and total phenol accumulation were investigated in greenhouse conditions. We demonstrated that application of 5mM salicylic acid through foliar spray could induce resistance against M. javanica in tomato. Polyphenol oxidase activity and levels of phenol compounds were determined on 1 to 8 days after inoculation. Salicylic acid caused increasing polyphenol oxidase activity that reached maximum level 4 days after nematode inoculation. The highest level of phenolic compounds was observed 4 days after Salicylic acid and nematode inoculation. Also، application of Salicylic acid could decrease the severity of disease in greenhouse. In iddition، in vitro assay showed that salicylic acid increased the death percentage of second stage juvenile (J2). The results showed the induced resistance observed in tomato against M. javanica via application of Salicylic acid، because SA increased the activity of polyphenol oxidase and levels of phenol compounds.

Ground beetles (Carabidae) with more than 40,000 described species worldwide are one of the main generalist predator groups and have an important role in reducing pest population and enhancing biodiversity of agricultural and wild ecosystems. Specimens from different agricultural and forest ecosystems in Azadshahr region, Golestan province, northern Iran, using pitfall traps and light traps, Berlese funnel and hand were picked during 2009 and 2010. Overall, 50 species belonging to 13 subfamily, 20 tribes, and 34 genera from ground beetles were collected and identified. Among them two species, Paratachys turkestanicus (Csiki)and Notiophilus danieli Reitter are newly recorded from Iran. Because of high activity of this family in crop fields and orchards of the region, implementing conservation programs was recommended to conserve or enhance the population of these generalist predators in studied ecosystems.

Currently, chemical pesticides and radioactive rays are widely used for control of stored product pests. Fumigation plays a major role in insect pest elimination in stored products. Phosphine and methyl bromide are the two common fumigants used for stored-product protection world over. Insect resistance to phosphine is a global issue now and control failures have been reported in field situations in some countries. Methyl bromide, a broad-spectrum fumigant, has been declared an ozone-depleting substance and, therefore, is being phased out completely. In view of the problems with the current fumigants, there is a global interest in alternative strategies including development of biological control. An experiment was performed to determine the effectiveness of Steinernema feltiae on adults of flour beetle (Tribolium confusum Duval) under laboratory conditions. The activity of entomopathogenic nematode was evaluated at five different concentrations (0, 25, 50, 100 and 200 infective juveniles per insect) in four different temperatures (25, 27.5, 30 and 32.5 ºC ±0.5). Insects were placed on filter paper impregnated with 1 ml of suspension in 9 cm petri dishes, and dead insects were counted every 24 h. The Maximum mortality of the adults observed in 200 IJs/insect, after 72 hours of exposure at 27.5ºC was 67.5%.

fruit fly, Ceratitis capitata (Diptera:Tephritidae), worldwide. To determine the best combination of trap and attractant for mass trapping of Mediterranean fruit fly, a field experiment was conducted in a Randomized Complete Block Design (RCBD) with 6 treatments in 3 replications in a pomegranate orchard in Shiraz (Iran) in 2009. Treatments included: 1-Jackson trap baited with Trimedlure, 2- McPhail trap baited with Trimedlure, 3- Tephri trap baited with Biolure, 4- Tephri trap baited with Cera trap liquid, 5- Plastic bottle baited with Cera trap liquid, and 6- Yellow sticky cards. Traps were installed on pomegranate trees at an early stage of fruit color changing. They were checked weekly and the number of captured flies and non -target insects were recorded. The mean number of total captured flies per treatment per day (FTD) and non- target insects per treatment per day (NTID) was calculated. Data were exposed to analysis of variance (ANOVA) followed by Duncan’s Multiple Range Test (DMRT). Results revealed significant differences among the treatments at probability level of 0.01. FTD were 0.77, 1.90, 0.58, 0.2, 0.13 and zero respectively but NITD were 0.01, 0.02, 2.46, 4.19, 6.79, and 0.74, respectively. In total, 85.6 percent of the total captured insects in all traps included non-target insects. Minettia sp. (Dip.: Lauxaniidae), Drosophila melanogaster and Zaprinous indica (Dip: Drossophildae) were the dominant species among the non-target insects. The total captured adult males in treatments one and two were more than 95 percent, and in treatments 3, 4 and 5, they constituted 24, 27 and 22.5 percent, respectively. Finally, McPhail trap baited with trimedlure was the best combination among all treatments from technical, ecological and economical aspects.

Rice is the world's most important food crop. To decrease the damage of rice pests, development of insect pest management strategies in rice is necessary. Biennial results for determination of a suitable method to control striped stem borer in rice showed that integration of two methods of control (biological and mechanical) is a feasible effort to reduce stem borer infestation. To assure this result, The current study was carried out at the farmer's field on Hashemi Tarom variety in east (Neka city), center (Babol city) and west (Noor city) of Mazandaran province with the purpose of determining the efficiency of the two control methods especially, mechanical control, because of its economic and environmental properties. The experiment was carried out in randomized complete design with 4 treatments (Mechanical control, Mechanical-biological control, Mechanical- Biological-chemical control and usual method of farmer, namely two times application in first and second generation) and 3 replications. Whiteheads and yield were measured before harvesting. Data were compared by one-way Analysis Of Variance (ANOVA) followed by Duncan test. The parameters were analyzed by using the SAS software. Results showed that there were significant differences among different control methods. The highest mean of whitehead rate (14.2%) and the lowest mean yield (3.854 t/h) occurred in the conventional method (P<0.05). There were no significant differences among other control methods. The results of this study showed the efficiency of the mechanical method.

Wheat is the most important crop of Iran and black or stem rust disease is one of the most severe diseases threatning the wheat production. In order to identify new resistant sources against the new race of stem rust virulent on plant with Sr 31gene, the selected Iranian landraces accessions of National Plant Gene Bank of Iran wheat collection were evaluated. The most virulent isolate of Puccinia graminis f.sp. tritici (Pgt) that was from Dasht-Azadegan was used. Isolate purity was tested by propagation of single pustule on seven days seedling of Boulani susceptible cultivar in the green house. Pathotype identification was carried out by 45 differential lines of wheat stem rust received from ICARDA. The Pathotype used was pathogenic against Sr31, Sr36, Sr38 and Sr13 but it was not pathogenic against Sr24. During this study, 62 Iranian landrace accessions were evaluated for resistance against Pgt at seedling stage in the greenhouse. Seven days seedlings were inoculated by spore suspension. 14 days after inoculation based on Stackman et al. method, infection type was recorded. According to the results, the landrace accessions were divided into susceptible and resistant groups. The resistant group included 39 landrace accessions. Complementary analysis for identification of resistance genes by molecular markers is in progress.

Understanding of parameters that influence parasitoids fitness is necessary for mass rearing and effective use of parasitoids. Host quality is an intrinsic feature that is determined by quantitative and qualitative differences in hosts. These differences can change nutritional resources available and consequently affect life history traits of parasitoid. In this study, parasitoid wasps Lysiphlebus fabarum were reared on different growths stages of black bean aphid, Aphis fabae Scopoli, including four instars and adult aphid, to identify the parameters determining fitness of wasp. The results showed that total development time was increased with host body size, such that these periods were determined 10.75±0.08, 11.57±0.07, 11.93±0.13, 12.59±0.10 and 12.61±0.06 days from 1st to adult aphids, respectively. Body sizes of wasps were reared in 1st, 2nd, 3rd, 4th instar nymphs and adult aphids did not follow any specific function. The largest wasps were produced in second nymphal instar of aphids and then adult aphid, third, fourth and first nymphal instars were respectively. The highest emergence rate was obtained in wasps reared in adult aphid with 95.91% and the lowest emergence rate was 81.57% in fourth nymphal instar. Furthermore, rearing the wasps in different growth stages of the aphid had a significant effect on the wasp longevity, and maximum longevity was observed in the wasps reared in third nymphal instar. According to this study, the greatest fitness was achieved when the wasps were reared in second nymphal instar of aphids.