Preference by Adult Female Riptortus Clavatus Thunberg for Plants from the Fabaceae and Other Plant Families

To obtain basic knowledge regarding the preference of adult female Riptortus clavatus for particular host plants, we investigated the preference of R. clavatus for green soybean, common bean, and cow pea as host plants, and between cow pea and either bell pepper, lettuce, cabbage, or cucumber. R. clavatus indicated a preference for cow pea over green soybean, followed by common bean. In addition, it was indicated that R. clavatus can distinguish among host plants. R. clavatus preferred cow pea over various non-host plants to a highly significant degree. These results clarified that adult female R. clavatus have strong ability to distinguish among host and non-host plants in the Fabaceae

Repellent Effect of Neem against the Cabbage Armyworm on Leaf Vegetables

We investigated the pest repellent effect of azadirachtin formulation and neem seed kernel oil cake. In laboratory tests, the repellent effect of komatsuna and spinach treated with azadirachtin formulation or neem seed kernel oil cake for 7 days on the feeding cabbage armyworm were evaluated. The feeding repellent effect of azadirachtin formulation treatment was equivalent to that of commercial biological pesticide, while the effect of neem seed kernel oil cake treatment was higher. This result clarified that neem seed kernel oil cake has a high feeding repellent effect against cabbage armyworms. In field tests, although the feeding percentage for komatsuna and spinach controls was 70%, that for komatsuna and spinach treated with azadirachtin formulation and neem seed kernel oil cake was about 40% and 30%, respectively. These laboratory and field test findings demonstrated that despite having an affect less than that of azadirachtin, neem seed kernel oil cake is a high effective feeding repellent

VARIETAL DIFFERENCES IN ZINNIA HYBRIDA FOR REMEDIATION IN OILCONTAMINATED SOIL

In this study our goal was to select the variety of Z. hybrida that shows the best growth in oilcontaminated soils and the highest remediation of contaminated soil. We chose ‘Profusion White’, ‘Profusion Cherry’ and ‘Profusion Orange’ in Z. hybrida cultivars and cultivated the plants under 18,597 mg diesel/Kg soil condition. The dry weights of shoot and root of ‘Profusion White’ were more than ‘Profusion Cherry’ and ‘Profusion Orange’. Soil total petroleum hydrocarbons (TPH) concentration decreased in all three varieties throughout the study period and no significant differences could be observed among the varieties. Dead cells of plant roots and rotten roots after plant death are nutrient sources for microorganism in soil. We propose that ‘Profusion White’, whose root growth was the greatest among the three varieties, is the best suitable variety for the remediation of oil-contaminated soil under the initial soil TPH concentration of 20,000 mg/kg

Effect of Replanting Zinnia Plants for Remediation of Oil-Contaminated Soil

Previously, we demonstrated that the zinnia plant was effective for the phytoremediation of oil-contaminated soils and that it had a higher remediation effect during the initial growth period. Therefore, repeated planting of zinnia for the initial growth period might enhance the remediation of contaminated soils, so we performed the following study. Seeds were sown in soils containing 4% (w/w) diesel oil and grown for 100 days. We carried out two treatments: replanted plots where above-ground parts of plants were cut after 50 days, and new seeds were sown; or non-replanted plots where plants were allowed to grow for 100 days. The soil dehydrogenase activity and soil total petroleum hydrocarbon concentrations were analyzed. At the end of the study, no significant differences were found between replanted and non-replanted plots for either measurement. Therefore, replanting did not affect remediation. Degradable oil components in the soils may have been degraded in the initial growth period of the first planting, but by the time of replanting there may have been few degradable oil components left in the soil, so there was no beneficial effect of replanting. We concluded that replanting is unsuitable for phytoremediation of oil-contaminated soils

Disinfection by Ozone Microbubbles Can Cause Morphological Change of Fusarium oxysporum f. sp. melonis Spores

To investigate the difference in the disinfectant efficiency of ozone microbubbles (O₃MB) and ozone millibubbles (O₃MMB), the morphological change of the treated Fusarium oxysporum f. sp. melonis spores was observed with scanning and transmission electron microscopies (SEM and TEM). The disinfectant efficiency of O₃MB on F. oxysporum f. sp. melonis spores was greater than that of O₃MMB. On observation with SEM, it was revealed that morphological change of F. oxysporum f. sp. melonis spores was caused by O₃MB and O₃MMB, and damage to the spore surfaces by O₃MB occurred sooner than that by O₃MMB. On observation with TEM, it was furthermore confirmed that F. oxysporum f. sp. melonis spores treated with O₃MB induced wavy deformation of cell membrane and the intracellular change different from that with O₃MMB. Therefore, the greater disinfection efficiency of O₃MB was suggested to be caused due to the function of the MB in addition to the oxidative power of O₃