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In acidic solution, a significant enhancement of the photoelectrochemical response of a TiO2electrode for visible light irradiation is achieved by coating the electrode with a film of (tetrakis(4‐carboxyphenyl)porphyrinato)Zn(II).

Synthetic pyrethroids are considered to have great prospects for insect control due to their high insecticidal activity combined with lowmammalian toxicity. Different substituted 3-methyl-2-phenoxy butanoic acids were prepared by the reaction between 2-bromo-3-methyl butanoic acid and phenols with fluoro, chloro, bromo, methoxy and trifluoromethyl substituents in the para position. The acid chlorides of theseacids were made to react with penta fluorobenzyl alcohol to give thepyrethroid esters. Out of the five pyrethroid esters, four compounds, I, II, III and IV with the respective fluoro, chloro, bromo and methoxy substituents in the phenyl ring of the acid moiety were found tobe effective for larvicidal activity with LC50 values ranging between 0,338 and 0.997 mg/l and adulticidal activity with LD50 values ranging between 0.022 and 0.940 mu g/insect againstCulex quinquefasciatus. [ABSTRACT FROM AUTHOR]

THAT zinc is essential for the growth of Fusarium vasinfectum has been established by one of us (L. S. D.)1. That the fungus produces certain phytotoxins in vitro and that one of them, namely, fusaric acid, possesses antibacterial properties also, has been reported earlier2. The present investigation has revealed a further relationship between zinc concentrations in a purified medium and antibiotic production.

A STUDY was made of the toxicity of culture filtrates of the cotton–wilt pathogen, Fusarium vasinfectum Atk., grown in synthetic Czapek's medium, to cut shoots of cotton. This indicated that, under laboratory conditions, the culture filtrate (fourteen days old) when dialysed against distilled water at 4–5°C. for four days to rid the crude filtrate of metabolites—earlier observed to be toxic to the plant—brought about typical wilt symptoms, which have been described in detail elsewhere1. Higher dilutions of this dialysed neat filtrate did not produce any symptoms of toxæmia, but induced rooting. However, the dialysed filtrate autoclaved at 15 lb. pressure for 15 min. (with the view of inactivating the toxin) induced profuse rooting in the cut shoots of cotton at all concentrations, and in no case were there any typical wilt symptoms.