PLANT PEST RESEARCH
Year:2014 | Volume:4 | Issue:1|Papers Count:7

Knowledge of spatial distribution pattern provides useful information about the main behavior of a species. From research point of view, dispersion pattern data could be useful for determining sampling pattern, optimal sample size and organizing sequential sampling plan. Sampling of pest and natural enemies populations is a key component in each integrated pest management program. From April to June 2010, cabbage aphid, Brevicoryne brassicae (L.) and its parasitoid Diaeretiella rapae Mc’ Intosh populations were sampled in two canola fields irrigated with two different methods (flooding and sprinkler irrigations) weekly. Taylor’s power law and Iwao’s patchiness regression methods were applied for determining spatial distribution pattern. Using Taylor’s power law the b coefficient for cabbage aphid population in sprinkler and flood-irrigated canola were 1.77±0.211 and 1.759±0.122 and for D. rapae were 1.493±0.0667 and 1.527±0.125 respectively. These parameters showed the clumped dispersion pattern for both species at both irrigation systems. Scince Taylor’s power law described variance - mean relationship better, estimated α and β were used for developing a fixedprecision sampling plan for cabbage aphid. The obtained results could be useful for management of B. brassicae in canola fields.

In order to identify and investigate the biodiversity of Noctuidae family in Khorasan Shomali province, different geographic locations were sampled during 2010-2011. Seven species belonging to subfamilies Catocalinae, Psaphidinae and Xyleninae were identified which are reported from Khorasan Shomali Province for the first time. Beside the descriptions, diagnostic comparisons with related species, distribution and identification keys are also presented. The list of identified species is as follows: Catocala elocata (Esper, [1787]); Clytie distincta iranica Brandt, 1939; Drasteria saisani (Staudinger, 1882); Allophyes asiatica Staudinger, 1891; Agrochola lychnidis ([Denis & Schiffermüller], 1775); Conistra torrida (Lederer, 1855); Ulochlaena hirta (Hübner, [1813])

The current study aimed to investigate the genetic structure of common pistachio psylla (Agonoscena pistaciae Burckhardt & Lauterer) populations in some pistachio planting areas in Kerman province with different chemical control management programs. sampling was conducted in different regions including: Zangi-abad Kerman and Haft bagh Kerman (regions with severe chemical control), Dashtab Baft (region with low chemical control) and Esfandagheh Jiroft (region without chemical control) during July-August in 2012. DNA of specimens were extracted with Chelex method and amplified with eight RAPD primers including: OPA-01, OPA-02, OPA-03, OPA-04, OPA-07, OPB-07, OPK-17 and OPO-05. After observation and scoring bands patterns, data were analyzed with NTSYS and POPGENE softwares. Accordingly, OPA-02 was found the most useful primer, that created the greatest amount of PIC with the rate of 0.395. The results of similarity and genetic distance between populations based on Nei’s method also showed that the low chemical control and the severe chemical control regions with a genetic distance of 0.0714 have the greatest genetic distance and also the region with the low chemical control had the highest similarity with the regions without chemical control. Individuals were clustered using Jacard similarity index. Results indicated that RAPD primers could separate populations with severe chemical control in a group compare to other regions where, population of two regions of Esfandagheh and Dashtab were clustered in the same group. These result showed that heavy chemical control in some regions could probably result in differences among genetic structures of active populations of this pest.

The aim of this study was to evaluate application of Neem (Azadirachta indica) extract with Beauveria bassiana against sawtoothed beetle in the nutritional status of the dates. The compatibility between Neem and the fungus was evaluated based on mycellial growth and spore germination of B.bassiana by extract medium mixing method. The lethality of Neem extracts individually and in conjunction with B. bassiana in the adult and larval population were evaluated by dipping bioassay method. Studies revealed that mycelial growth and spore germination of B. bassiana in 250 ml/L concentration of Neem were 3.1 and 2.5% respectively less than control treatment.50% decreasing in mycelial growth and spore germination was happened at 3679.4 and 1949.4 ml/L of Neem extract respectively. The highest Compatibility of B. bassiana was 76.89% recorded at 250 ml/L of Neem extract. The average of LC50 in larva and adult population for the fungus was 3.31×102 and 2.5×104 conidia/ml respectively and while with usage neem extract was 386.1 and 696.4 ml/L respectively.According to the results, usage both of Neem extract and Beauveria bassiana increases mortality rate of adult and larval population of sawtoothed beetle based on SR indeices with 1.57 and 1.98 reppectivaly. Combined usage of neem extract and fungus B. bassiana can increase performance and provide the final formulation as a means of pest management to store dates.

Two aphid-attacking parasitoids, Aphelinus chaonia Walker and Aphelinus varipes (Förster) (Hym.: Aphelinidae) were collected from corn aphids in Moghan region (Northwest Iran). Of two species, Aphelinus chaonia is first reported from Iran. Six known Iranian species of Aphelinus are reviewed and an identification key is provided for them.

The Clearwing moths (Lep.: Sesiidae) are important and destructive pests of fruitful and non- fruit bearing trees in different countries of the world. Considering the high damage of sesiid moths in Isfahan landscape, the infestation percentage and intensity were studied on 4768 trees of different species in 14 Isfahan municipality regions, Isfahan University of Technology campus and Nazhvan parks as 15th and 16th regions, respectively. To identify sesiid moth species, DNA was extracted from larvae and adults. Polymerase Chain Reaction (PCR) was used to amplify a 709-bp region of the mitochondrial DNA cytochrome oxidase I and samples were sequenced. Results of COI sequences revealed that the moth Synanthedon caucasica (Gorbunov) is the damaging species on Platanus orientalis, Ulmus carpinifolia and U. carpinifolia var umbraculifera and the sesiid moth Sesia pimplaeformis (Oberthür) (=Eusphecia pimplaeformis) is harmful to Salix alba and Populus alba.Percentage of infestation was calculated based on the number of infested trees divided by total trees and intensity of infestation was determined based on the total number of pupal exuviae, active larval holes and inactive larval holes per 10 centimeters of trunk diameter. The combined analysis was performed in a completely randomized design with 10 replicates. The regions and hosts were considered as main and secondary factors, respectively. Using linear regression between tree diameter and infestation rate, the effect of trunk diameter on the infestation rate was determined. Results showed that 53.8 % of Platanus orientalis, 65.6% of U. carpinifolia, 64.4% of U. carpinifolia var umbraculifera, 52.6% of S. alba and 45.2% of P. alba and totally 53.2% of all trees were infested with sesiid larvae. The highest infestation intensity (4.2) was observed on U. carpinifolia var umbraculifera. The species U. carpinifolia, Platanus orientalis, salix alba and P. alba had lower infestation intensity. No sesiid damage symptoms were observed on Morus spp., Rubinia pseudoacacia and Fraxinus rotundifolia subsp. persica. On all host tree species, the correlation between trunk diameter and infestation rate was positive but a significant correlation (p<0.05) was only occurred in U. carpinifolia var umbraculifera and salix alba.

Colorado potato beetles, Leptinotarsa decemlineata Say (Col: Chrysomelidae) is one of the most economical destructive pest of potato. In this study, the effect of field recommendation doses of pyridalyl, thiamethoxam and lufenuron was investigated against larvae of the pest in a completely randomized block design with four replications under field conditions. The mortalities were recorded at 1, 3, 5, 7, 10, 13, 15 and 20 days after spraying. The control plants were treated with water. Based on the results, thiamethoxam had the most and fastest effect compared to pyridalyl and lufenuron. Thus, the yield in plots treated with thiamethoxam was higher than that of pyridalyl and lufenuron.