Pesticidal activity of virginiamycins S1 and M1.

Virginiamycins S1 and M1, two major components of the antibacterial antibiotic complex produced by Streptomyces virginiae and used as an animal growth promoter in animal husbandry, exhibited a selective insecticidal activity against Leptinotarsa decemlineata comparable with the effect of the organophosphorus pesticide Metathion. An acaricidal effect of the two compounds on eggs of Tetranychus urticae was also observed.

Macrotetrolide antibiotics produced by Streptomyces globisporus.

Macrotetrolides isolated from a new producer, Streptomyces globisporus, were identified as nonactin, monactin, dinactin and trinactin. Spectroscopic characterization of these compounds was extended by 13NMR spectra. Chemical ionization with ammonia as reactive gas was proposed for mass-spectroscopic characterization of their mixtures. Their biological activity was confirmed by using larvae of the Colorado potato beetle (Leptinotarsa decemlineata) as a new test model.