The root powder of Stellera chamaejasme was extracted with petroleum ether. The crude extract obtained was chromatographed repeatedly with silica gel columns. One pure natural product was obtained, which was identified as 5-isopropyl-2-methylphenol (carvacrol), separated for the first time from the root of S. chamaejasme. The results of a laboratory bioassay showed that it had good insecticidal activity against Aphis craccivora and Leucania separata. Its median lethal concentrations (LC(50)) (24 h after treatment) were 16.8 and 12.7 mg L(-1), respectively. This is the first report of the insecticidal activity of carvacrol against A. craccivora and L. separata.

Thirty-one new 4H-chromene derivatives were designed and synthesized. Their structures were identified with IR, 1 H NMR, 13 C NMR, and HRMS. The crystal structure of compound 2a was determined by single-crystal X-ray diffraction. Their antifungal activities were evaluated against Pyricularia oryzae, Erysiphe graminis, Coniella diplodiella, Pseudoperonospora cubensis, and Sclerotinia sclerotiorum. These results demonstrated that most compounds exhibited remarkable inhibitory activities at 20 μg/mL. Compounds 4b and 4c displayed excellent antifungal activity against S. sclerotiorum and possessed better efficacy than fluopyram. At the same time, the inhibitory activity of the bioactive compounds was evaluated against succinate dehydrogenase (SDH). The results showed that these compounds possessed outstanding activity. Compounds 4b and 4c displayed better inhibitory activity than fluopyram. The molecular modeling results revealed that compound 4c had stronger affinity to SDH than fluopyram. It is the first time that the inhibitory activity of 4H-chromene analogs against SDH has been reported.

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Green tides" are vast accumulations of unattached green macroalgae associated with eutrophicated marine environments. It had major ecological and economic impacts globally, thus understanding of their detailed conditions was required to inform management decisions. Chaetomorpha valida (Cladophoraceae, Chlorophyta), as a fouling green alga, was found in aquaculture ponds along the coast of Dalian and Rongcheng cities, People's Republic of China in the past few years. Seasonal abundances of this macroalga in China have presented a significant nuisance and caused great loss to the local aquaculture. Using unialgal cultures, the effect of temperature and irradiance on growth and reproduction were investigated. Healthy growth and reproduction occurred in the range of 17-29°C while the upper lethal limit was at 33°C. A suitable temperature range over 21-29°C and a relatively high irradiance of 108 μmol photons m −2 s −1 were more favorable for growth and reproduction. According to our observations, the diversity of reproductive approaches and wide adaption to temperature can be considered to be key factors that facilitate its excessive growth and colonization in spring and summer. Our results provide a basis for establishing a forecast system and taking remediation measures against seasonal green tides of this macroalga.