More than half of the worldwide expenditure on agrochemicals was devoted to insecticides to combat over half a million herbivorous insect species, yet 15% of crops are lost to pests, driving demand for more effective and environmentally friendly crop protection agents. Natural products are ideal sources, so we screened nitrogen-fixing Streptomyces spp. from China. Preliminary bioassays showed Streptomyces griseofuscus (MS/ZD/033) produced the most active metabolite against Aedes aegypti larvae. Mosquitocidal-assay-directed purification yielded compound 1, identified as indanomycin via 1D/2D ¹H/¹³C NMR and MS. Compound 1 exhibited bactericidal activity against Streptococcus aureus and Staphylococcus epidermidis at 1 ppm (no activity against fungi/yeast at 100 ppm), insecticidal activity with 50% weight reduction for Manduca sexta (tobacco hornworm) and Lymantria dispar (gypsy moth) neonates at 100 ppm after 6 days (33% reduction for Helicoverpa zea (corn earworm)), and mosquitocidal activity causing 100% mortality in 4th instar A. aegypti larvae at 20 ppm. This is the first report of indanomycin's circular dichroism (CD), insecticidal, and mosquitocidal activities.