Stimulative activity of nutrient chemicals including 9 sugars, 20 amino acids, 9 vitamins, 2 sterols, 4 lipids and 4 salts on the feeding of Gallerucella vittaticollis BALY was investigated. Of the sugars tested, sucrose and D-fructose appeared to be active feeding stimulants.D-Glucose showed slight stimulative activity. D-Fructose and D-glucose were determined in leaves of Rumex obtusifolius and Fragaria chiloensis, hosts of this insect, but sucrose did not occur in these plants.From these results, D-fructose and D-glucose seemed to be the stimulants in the feeding of host plants in this insect. Among the amino acids, L-alanine alone was inactive but slightly active as feeding stimulant in the presence of sucrose, whereas other amino acids were inactive with or without sucrose. The quantitative determination of free amino acids in the leaves of R. obtusifolius and F. chiloensis showed that L-alanine content was much higher than any other amino acids. It is noteworthy that L-alanine stimulating the feeding of this insect was the most abundant amino acid in these host plants. Vitamins, sterols, lipids and salts were showed to be inactive with or without sucrose.
When either topically applied or mixed in the diet, CME-134, 1-(3, 5-dichloro-2, 4-difluorophenyl)-3-(2, 6-difluorobenzoyl)urea, prevented pupation in last instar larvae of Mamestra. CME-134 was about 5 times as effective as diflubenzuron by topical application, with its LD5D value being 0. 016g/insect. By dietary administration, the LD50 values of both insecticides were almost same (0. 02 ppm) but CME-134 was about twice as effective as diflubenzuron when the LD100 values were compared. After application of the same doses of both CME-134 and diflubenzuron to last instar larvae, chitin synthesis was studied by measuring 14C-GA incorporation into cuticle and midguts. CME-134 inhibited chitin synthesis in vivo. The inhibition by CME-134 progressed faster than by diflubenzuron, although CME-134 was a less potent inhibitor than diflubenzuron for chitin synthesis in vitro using cuticle and midguts. The results suggest that the insecticidal activity of CME-134 is based on strong inhibition of chitin synthesis as so is that of diflubenzuron. CME-134 did not inhibit chitin synthetase that was prepared from the midguts of last instar Mamestra larvae even at a concentration of 1.0x10-4M.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.