• Korean journal of applied entomology
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• v.56 no.4
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• pp.395-402
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• 2017

Overuse of synthetic pesticides caused negative side-effects such as environmental contamination, development of insect pests' resistance, and effects on non-target organisms. Plant origin substances without/or with low mammalian toxicity have been considered as promising alternatives to the synthetic pesticides. Fumigant toxicity of the essential oil of Iranian Yarrow, Achillea millefolium L., was investigated against a cosmopolitan stored-product insect pest: saw-toothed grain beetle (Oryzaephilus surinamensis L.). Chemical profile of this essential oil was studied by Gas Chromatography-Mass Spectrometry. Tested concentrations were significantly effective to the mortality of insect pest. A positive correlation between essential oil concentrations and pest mortality were realized. LC50 value (lethal concentration needed to 50% mortality) was achieved as $17.977(16.195{\pm}20.433){\mu}l/l$ air. The main components were 1,8-Cineole (13.17%), nerolidol (12.87%), ${\alpha}$-cubebene (12.35%), artemisia ketone (6.69%), ${\alpha}$-terpineol (5.27%), alloaromadendrene oxide (4.71%) and borneol (3.99%). Terpenic compounds including monoterpene hydrocarbons (8.19%), monoterpenoids (44.23%), sesquiterpene hydrocarbons (21.69%) and sesquiterpenoids (22.24%) were 96.35% of the total identified compounds. Results indicated that the terpene-rich A. millefolium essential oil may be considered as a safe bio-agent in the O. surinamensis management.

• Microbiology and Biotechnology Letters
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• v.17 no.2
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• pp.142-147
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• 1989

Six plasmids of B. thuringiensis serovar. kurstaki HD73 were detected, with approximate sizes of 7.4, 7.8, 8.1, 11.3, and 75 Kb, as well as a low copied plasmid of similar length to 75 Kb. Partially cured mutants from B. thuringiensis HD73 were obtained either by the treatment of the curing agent, ethidium bromide(0.02 $\mu\textrm{g}$/$m\ell$) or by spontaneous curing, Acrystalliferous mutants(Cry$^-$) were identified by microscopic observation and immunoblotting with polyclonal antibody against 133 KD deltaendotoxin of HD73. Ten Cry$^-$ mutants were found to be lack of 75 Kb plasmid. These results implicated that this plasmid was associated with delta-endotoxin production, After isolating the mutants, we streaked them on potato dextrose agar, spizizen casamino acid glucose, starch agar, and nutrient agar. Only on starch agar medium did morphologies of Cry$^-$ appear translucent and light greyish. On the other hand, the mutants of B. thuringiensis isolated from Korean soil, designated KBS722, were obtained by the treatment of novobiocin (3 $\mu\textrm{g}$/$m\ell$). Acrystalliferous mutants of KBS722 were less translucent than HD73 mutants' only on nutrient agar medium. Compared the plasmid profile of the mutants with delta-endotoxin production, the results seemed to indicate that the insecticidal protein gene of B. thuringiensis isolates KBS722 located on about 225 Kb plasmid DNA.