AGRICULTURAL PEST MANAGEMENT
Year:2014 | Volume:1 | Issue:1|Papers Count:6

During a survey in north-west of Iran, an entomopathogenic nematode isolate named TS25 was isolated by Galleria baiting from soil samples collected near Sardroud, East Azarbaijan, North-west of Iran during 2012. Based on morphological and molecular characters as well as cross breeding test, it was identified as Steinernema carpocapsae (Weiser 1955). Morphology and morphometric characterization and comparison with All and DD 136 isolates revealed differences in ratios b and d between their infective juvenile and NR in males. There were no significant differences among other characters. Maximum parsimony constructed Phylogenetic tree based on the sequences of Internal Transcribed spacer of ribosomal DNA clearly showed that the studied isolate constitute well supported monophyletic group with well-known S. carpocapsae isolate All. In constructed Phylogenetic tree, S. scapterisci showed nearest genealogic relationship with S. carpocapsae. Bootstrap value showed that defined monophyletic group has high confidence. Here we describe TS25 isolate in details.

The Hypoaspis aculeifer Raumilben is a polyphagous species which has an important role in control of insects, mites, nematodes and fungus in the soil habitats and also is used as a biological control agent in greenhouses and fields. In this paper, the effects of constant temperature on the demography of H. aculeifer fed on Rhizoglyphus echinopus have been investigated. This study was done at eight constant temperatures (16, 17.5, 20, 22.5, 25, 27.5, 30, 32.5) oC, 60±5% RH and photoperiod of 16:8 (L: D). Net reproductive rate (R0) of the predacious mite was 0.91, 14.67, 21.87, 24.87 and 32.38  ♀/♀/G at 16, 20, 22.5, 27.5 and 30oC respectively. The intrinsic rate of increase (rm) values ranged from -0.002 (16oC) to 0.252 (30oC) d-1. The finite rate of increase (l) was 0.997 d-1 at 16oC, and 1.286 d-1 at 30oC. Using the linear model (Ikemoto and Takai), the low temperature threshold of H. aculeifer estimated for pre-adult stages and also for constant temperature were 10.8oC and 169.3 degree days for females and 11.2oC and 163.9 degree days for males. The estimations of the optimum temperature, low threshold and high threshold of development were estimated by chosen models (Analytis (1) / Allahyari, Analytis (2), Analytis (3), Analytis (1)).

The insecticidal and antifeedant properties of ethanol extract of Calotropis procera were investigated on the flour beetles, Tribolium spp., and Thiacidas postica by the food disc and sandwich procedure. The experiments were carried out according to a completely randomized design with four treatments and five replications. The obtained results showed that all pupae of the flour beetles died at the concentrations of 90 and 120 ml/disc. At the other concentrations, the weight and growth of the adults were significantly different with the control. The mortality of neonate larvae of T. postica at the all concentrations was significantly greater than control. The feeding rates of the third and fifth instar larvae of T. postica at the concentrations of 30 and 60 ml/cm were significantly different with the other treatments. The results revealed that the amount of leaf consumption at the 30 and 60 ml/cm was higher than the other concentrations; consequently, the insecticidal and antifeedant properties were occurred at the low and high concentrations, respectively. The ethanol extract of C. procera had a noticeable effect on the relative growth rate (RGR) and relative consumption rate (RCR) at all concentrations except for 30 ml/disc concentration. In addition, the greatest influence on the efficiency of conversion of ingested food (ECI) and feeding deterrence index (FDI) was observed at the concentrations of 60 and 120μl/disc, respectively.

Habrobracon hebetor Say is an important ectoparasitoid of various lepidopterous larvae. In this study, lethal and sublethal effects of diazinon were evaluated on H. hebetor under laboratory conditions. The adults were exposed to fresh residue of the insecticide applied on glass plates at 26±1oC, 60±5% RH and a photoperiod of 16:8 (L: D) h. Based on the dose-response study, the LC50 value of diazinon was 6.38 mgr a.i. ml-1. In order to assess the sublethal effects of the insecticides, adult wasps were exposed to an LC30 of the insecticide and then the demographic parameters of live wasps were studied. The results showed that LC30 concentration of diazinon negatively affected the stable population and biological parameters (e.g., rm, l, DT, T, eggs laid, hatch rate). The sex ratio of H. hebetor offspring was not significantly affected by the insecticide treatment. The results indicated that diazinon has negative effects on demographic parameters of the parasitoid and semi-field and field tests seem to be necessary.

The population fluctuation of predacious species of syrphid flies was studied in rapeseed fields of Kermanshah province in 2011-12. Malais traps were used for collecting syrphid flies and larvae were collected and reared in laboratory. For sampling cabbage aphid, a number of infested foliage as well as rate of infestation was assessed on five randomly selected foliage belonging to 10 plants. The surveys were done both in sprayed and nonesprayed fields. Overall 11 syrphid species were collected and identified in these fields. Eupeodes corollae was regarded as predominant species. This study indicated that the syrphid flies spent two generations from April to July. The study showed that Brevicoryne brassicae had only one peak at the same duration. The peak of aphid population occurred just after the first peak of syrphid population. At this time syrphid flies were observed as larvae and egg stages in the field. In sprayed field populations, both syrphid flies and cabbage aphid reduced following spraying and increased again after a while, but the population level was not as high as that of the none-sprayed field.

Two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae) is an important pest of ornamental plants such as rose in many regions of the world. Reproductive parameters of this mite were evaluated on 10 roses cultivars, including Valentine, Pink, Yellow, Roulette, Tea, Marusya, Cool water, Dolcevita, Bella vita and Orange in a growth chamber at 24±1oC, 65±5% RH and 16 L and 8 D. Results showed that the gross and net fecundity rate were significantly different on rose cultivars. The highest gross and net fecundity rates were calculated on the Pink cultivar (113.86±11.50 and 84.64±8.10, respectively). Also, the highest gross and net fertility were observed on the same cultivar (94.89±9.57 and 70.54±7.50, respectively). Mean eggs per female per day and mean fertile eggs per female per day were significantly different among the rose cultivars, and the value of these parameters were the highest on the Orange cultivar and lowest on the Cool water cultivar. The life expectancy at adult emergence was highest on the Pink and the lowest on the Bella vita. Based on the results, it could be concluded that the Pink cultivar is the most suitable host plant among the examined rose cultivars for the reproduction of two spotted mite.