فصلنامه گیاه پزشکی
سال سی و ششم شماره 2 (تابستان 1392)

Saffron is one of the most valuable agricultural products. Saffron, as other crops, could be affected adversely by several factors, including Rhizoglyphus robini. This mite is a polyphagous pest and can remain in soil for a long time. R. robini is known as the main limiting agent in saffron cropping. The present experiment was carried out in randomized complete block design with three replications on the farm of Gonabad Agricultural Research Station during growing season of 2007. Manure levels, i.e. 0, 20 and 40 ton/ha, were placed in main plots. Subplots consisted of five treatments of duration of solarization i.e. 0, 10, 20, 30 and 45 days, performed by transparent plastic laminate before planting. Results revealed that both factors can significantly affect the mite population and flower production. During first year of the experiment, as solarization duration and manure level increased, mite population decreased while after that, mite population increased gradually. Soil solarization for 30 days was the most effective treatment in mite population control. Maximum total yield and minimum mite density was obtained with 20 ton/ha of manure and 30 days of solarization.

The common pistachio psylla، Agonoscena pistaciae Burckhardt and Lauterer (Hem.: Aphalaridae) is one of the most important pest of pistachio trees in Iran. Nowadays، numerous chemical pesticides are used to control the pest. The use of pesticides on the nanoscale can be considered as an alternative to long term usage of chemical pesticides، to reduce the amount of pesticides. In this research، Nano amitraz was synthesized through a solvothermal method and compared to the insecticidal activity of nano amitraz، amitraz and imidacloprid against the fifth instar nymphs A. pistaciae using nano amitraz. Insecticidal solutions of different concentrations (0. 03، 0. 07، 0. 18، 0. 42، and 1 µL mL-1) were prepared and tested on the 5th instar nymphs of common pistachio psylla. For comparison purposes، amitraz (0. 03، 0. 07، 0. 18، 0. 42، and 1 µL mL-1) and imidacloprid (0. 08، 0. 14، 0. 25، 0. 5 and 0. 8 µL mL-1) were also used as a conventional insecticide. The results showed that the average size of nano amitraz was approximately 53 nm. In the experiments، the LC50 value for nano amitraz، amitraz and imidacloprid were calculated to be 0. 03، 0. 17 and 1. 46 µL mL-1، respectively. Also، the study showed that nano amitraz had the highest insect mortality effect.

The grey field slug, Agriolimax agrestis L. is a pest of vegetable in northern provinces of Iran. Pest digestive enzymes are excellent targets for pesticide agents such as inhibitors. The digestive enzyme inhibitors are used for producing transgenic plants resistant to pests. To achieve this goal, it is necessary to find the nature and properties of these enzymes. In this research, the biochemical properties of α- and β-glucosidase in different parts of digestive system of A. agrestis were investigated. Results showed that the specific activity of β-glucosidases in intestine was higher than its activity in digestive glands. The optimal pH for α- glucosidase activities were 6, 5-6 and 6-7 in front parts of digestive system (esophagus and buccal bulb), intestine and digestive glands, respectively. Also, optimum pH for β- glucosidases activities were obtained as 5, 6 and 4-6 in front parts of digestive system, intestine and digestive glands, respectively. High α- glucosidases activities were found at temperature 60 °C. Also, the optimal temperature for β- glucosidases activities were 40, 50-60 and 50 °C in front parts of digestive system, intestine and digestive glands,, respectively. Estimation of kinetic parameter showed that Km values of the α-glucosidases in the front parts of digestive system, intestine and digestive glands were 2.44, 1.44 and 3.28 mM, respectively and Km values of the β-glucosidases in the front parts of digestive system, intestine and digestive glands were obtained as 1.24, 1.17 and 0.94 mM, respectively. Zymogram pattern in the native gel revealed that A. agrestis α- and β-glucosidase from digestive glands had one and two isoforms, respectively.

Scale insects as plant pests, in Behbahan, located in Khuzestan province, Southwest of Iran, were investigated between 2010 and 2012. A total of 21 species of scale insects were identified as follows: Diaspididae (8 species), Pseudococcidae (6 species), Coccidae (4 species), Eriococcidae (2 species) and Phoenicococcidae (1 species). Taxonomic characters of all species are briefly discribed and illustrated. For each species, data are recorded. Of these, the genus Paracoccus Ezzat and McConnell and the species Acanthococcus aceris (Signoret) are new records for the fauna of Iran. In addition, 9 other species are new to Khuzestan (*). The economic important species are discussed briefly. The identified species are as follows:DIASPIDIDAE: Aspidiotus nerii* (Bouche), Diaspidiotus armenicus* (Borchsenius), Lepidosaphes malicola* Borchsenius, Melanaspis inopinata* (Leonardi), Parlatoria blanchardi (Targioni-Tozzetti) P. crypta (McKenzie), P. oleae (Colvee) and Salicicola? kermanensis Lindinger. PSEUDOCOCCIDAE: Chorizococcus sp.*, Nipaecoccus viridis (Newstead), Paracoccus sp., Phenacoccus sp.*, Planococcus citri (Risso) and Trabutina serpentina (Green). COCCIDAE: Coccus¬ hesperidum (Linnaeus), Eulecanium tiliae* (Linnaeus), Parthenolecanium corni* (Borchsenius) and Saissetia oleae* (Olivier). ERIOCOCCIDAE: Acanthococcus aceris (Signoret) and Eriococcus spurius (Modeer). PHOENICOCOCCIDAE: Phoenicococcus marlatti (Cockerell).

Olive fruit fly is the most important pest of the olive orchards throughout the world. The study of biological indexes was conducted in olive orchards and laboratory at Tarom-Zanjan research station. Results revealed that adults appeared out of the pupae from mid. April while the first infection time was recorded in ‘Konservalia’ cultivar in early July of the 2007 but early June of the 2008. The detailed study of the injurious generation of the pest showed that adults mating occurred at 3-7 days and led to egg laying after 14 days; the time from egg incubation till 3rd instar larval exit lasted 34.7±2.14 days and sex ratio was calculated as 1:1 (female:male). Reaction of the olive cultivars (Konsearvalia, Mari and Zard) to the fly was different based on the final product of the orchard implying if the fruits are grown for table olive, the Konservalia, Mari and Zard may be damaged respectively but in the case of oil production the trend of damage will be shifted to Mari, Zard and Konservalia.

Imidacolprid and pirimicarb are conventionally used insecticides for controlling melon aphid، Aphis gossypii Glover in fields and glasshouses in Iran. Aphidius matricariae Haliday is one of the most impotant parasitoid wasps of A. gossypii. The sublethal effects of mentioned insecticides were investigated on orientation behaviour using olfactometer device. The mortality data were subjected to probit analysis for lethal concentrations calculations and confidence limits. Concentrations of 0. 3 and 4. 2 ppm (LC25) of imidacloprid and pirimicarb، respectively، were used for olfactometer tests. Adult females were exposed to dry residues on glass tubes for 24 h. Three day old survived wasps were used for orientation tests. Results showed that imidacloprid and pirimicarb had no effects on orientation behaviour of female wasps to the odour of cucumber leaves that were infected by melon aphid although orientation response of female parasitoids toward contaminated leaves to honeydew of aphids was affected by exposure to LC25 of two insecticides. But in all of the tests، access times to treatments by parasitoid wasps exposed to imidacloprid significantly exceeded control.

Common smut is the most important disease of maize in Iran and in many parts of the world. Since the best way to control this disease is identification and cultivation resistant varieties، 17 hybrids and 14 lines were tested in a field experiment as split plots in random complete block design with 4 replications. Plants were inoculated artificially by injection of spore suspension Ustilago maydis into the tip of ears at the time of tassel appearance. The reaction of lines and hybrids to the pathogen was determined as the percent infection of ears and disease severity، after the appearance of disease symptoms on ears. Also، the effect of disease on yield، 1000 grain weight، ear length، chlorophyll and florescence chlorophyll was measured. Statistical analysis of the data showed that there was a significant difference between hybrids and lines in reaction to disease such that among the hybrids there were، 3 sensitive، 7 semi sensitive، 6 semi resistant and resistant hybrid (K3547/3×K1264/1)، while among 14 tested lines، there were 1 sensitive، 8 semi sensitive and 5 semi resistant to disease. Also، the disease significantly decreased yield، 1000 grain weight and ear length in hybrids and lines. Reactions of these maize hybrids and lines to this disease and the effect of the disease on their agronomical characteristics are reported here for the first time.