Mona Yavar; Ali Mirshekar; Abbas Khani; Sara Ramroudi
Abstract
Two-spotted spider mite, Tetranychus urticae (Acari:Tetranychidae), is one of the most important pests in plants, especially crops that it has high reproduction and ability to develop resistance to chemical pesticides. Considering the increasing of environmental pollution due to chemical pesticides, ...
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Two-spotted spider mite, Tetranychus urticae (Acari:Tetranychidae), is one of the most important pests in plants, especially crops that it has high reproduction and ability to develop resistance to chemical pesticides. Considering the increasing of environmental pollution due to chemical pesticides, the use of plant extracts has received much attention as an alternative method due to their acaricidal activity. Therefore, this experiment was performed to determine the chemical compounds of Momordica charantia fruit extract and toxicity of hexane and ethanolic extracts of this plant on adults of two-spotted spider mite in a completely randomized design with the control in four replications for fumigant and contact toxicities and repellent activity. After 24 hours, the mortality of mites was recorded. The results of bioassays showed that the mortality rate of mites and the repellent effect elevated with increasing the concentration of M. charantia extracts. The hexane extract of M. charantia at the concentration of 1000 μg/cm2 had the highest mortality (75.56%) in contact toxicity. Ethanolic extract at the concentration of 1000 μl/l air had the highest mortality (79.89%) of mite in fumigant toxicity. The repellent effect increased to 80%, 5 hours after application of ethanolic extract by increasing the concentration from 200 μl. In M. charantia fruit extract, sixteen different compounds were identified in which monoterpenoids, linalool oxide, limonene oxide, and 8-hydroxilinalool, had the highest amount. Therefore, the ethanolic extract of M. charantia in high concentrations can be recommended due to its monoterpenoids to protect plants, especially crops, against two-spotted spider mite.
Mostafa Hamzei; Ali Mirshekar; Mohammad Salari; Abbas Khani; Seyed Kazem Sabbagh
Abstract
Abstract The Sugarcane grasshopper (Chrotogonus trachypterus) is one of the most important and indigenous and harmful pest of field crops in Sistan region of Iran and cause considerable damage especially during seedling stages. We conducted this study in order to introduction of a biocontrol agent to ...
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Abstract The Sugarcane grasshopper (Chrotogonus trachypterus) is one of the most important and indigenous and harmful pest of field crops in Sistan region of Iran and cause considerable damage especially during seedling stages. We conducted this study in order to introduction of a biocontrol agent to C. trachypterus in a completely randomized designs and factorial experiment with three replications using topical application under laboratory conditions. For inoculations, after the preliminary experiments, five fungal suspensions prepared at consecrations of 1×104, 1×105, 1×106, 1×107 and 1×108 conidia mL-1 in distilled water containing 0.05% Tween-80®. Grasshoppers typically inoculated under the pronotal shield using a Hamilton microaplicator. Control treatment were treated with distilled water containing 0.05% Tween-80® as surfactant. The corrected cumulative percent mortality was recorded daily until 15 days after inoculations. Percentage of insect mortality was analyzed using (log-probit) methods.Results showed T. harzianum was pathogenic to adult insects and insect mortality increased with increasing concentrations. The highest and lowest mortality observed at 108 conidia mL-1 and 104 conidia mL-1 with a 75 and 25 percent respectively (p50value was 1.01×106conidia mL-1. This is the first report of the pathogenicity of T. harzianum to the grasshopper, C. trachypterus.
