The American house dust mite, Dermatophagoides farinae Hughes, 1961 (Acari: Pyroglyphidae), is recognized as an important source of allergens in the domestic environment. An assessment was made of the toxicity of constituents from essential oil of cade, Juniperus oxycedrus L. (Cupressaceae), and related compounds as well as four experimental spray formulations containing the oil (10–40 g/liter sprays) to adult D. farinae. In a contact + fumigant mortality bioassay, methyleugenol (24-h LC50,5.82 μg/cm2) and guaiacol (8.24 μg/cm2) were the most toxic constituents to the mites and the toxicity of these constituents and benzyl benzoate did not differ significantly.
This study was conducted to determine the toxicity to adult Myzus persicae (Sulzer) and Aphis gossypii Glover of 88 plant essential oils and six experimental spray formulations containing bitter orange or marjoram oil was examined using the vapor-phase mortality and spray bioassays. Results were compared with those of two conventional insecticides deltamethrin and dichlorvos. As judged by 24 h LC50 values, bitter orange oil (0.0212 and 0.0192 mg/cm3) was the most active material, followed by marjoram, celeryseed, and cypress oils (0.0239-0.0508 and 0.0209-0.0542 mg/cm3). These essential oils were significantly less toxic than dichlorvos, respectively. These essential oils were consistently more toxic to adult M. persicae in closed versus open containers, indicating that toxicity was achieved mainly through the action of vapor. Bitter orange oil and marjoram oil applied as 1% spray provided complete mortality toward two aphid species adults. Reasonable aphid control in greenhouses can be achieved by a spray formulation containing the 1% oil as potential contact-action fumigant.
Inhibition of acetylcholinesterase (AChE) is one of the important modes of action available for the control of insects. An assessment was made of the electric eel AChE inhibitory activity of 55 endophytic fungi isolated from the leaves of Huperzia serrata collected in Eunshi, Hubei Province, China. Of 55 mycelial extracts and 55 ethyl acetate-soluble fractions from liquid culture of the fungi, the ethyl acetate-soluble fraction of strain ES056 exhibited strong AChE inhibitory activity (88%) at a concentration of 100 μg/mL. Based on morphological characteristics and nuclear ribosomal DNA ITS sequence analysis, this fungus showed greatest similarity to members of the order Eurotiales and was shown to be most closely related to members of the Aspergillus aculeatus group. It was designated Aspergillus sp. MY056. This strain merits further study as a potential anti-AChE product.
The objectives of this study were to identify QTLs for agronomic traits using introgression lines from a cross between a japonica weedy rice and a Tongil-type rice. A total of 75 introgression lines developed in the Tongil-type rice were characterized. A total of 368 introgressed segments including 285 homozygous and 83 heterozygous loci were detected on 12 chromosomes based on the genotypes of 136 SSR markers. Each of 75 introgression lines contained 0-9 homozygous and 0-8 heterozygous introgressed segments with an average of 5.8 segments per line. A total of 31 quantitative and 2 qualitative loci were identified for 14 agronomic traits and each QTL explained 4.1% to 76.6% of the phenotypic variance. Some QTLs were clustered in a few chromosomal regions. A first cluster was located near RM315 and RM472 on chromosome 1 with QTLs for 1,000 grain weight, culm length, grain width and thickness. Another cluster was detected with four QTLs for 1,000 grain weight, grain length, grain width and grain length/width ratio near the SSR marker RM249 on chromosome 5. Among the 31 QTLs, 9 (28.1%) Hapcheonaengmi3 alleles were beneficial in the Milyang23 background. ILs would be useful to confirm QTLs putatively detected in a primary mapping population for complex traits and serve as a starting point for map-based cloning of the QTLs. Additional backcrosses are being made to purify nearly isogenic lines (NILs) harboring a few favorable Hapcheonaengmi3 alleles in Milyang23 background.