Dispersal of Streptomycetes in Air

SUMMARY The number of streptomycete propagules trapped from air above a fallow plot depended on the amount of dust in the air. Less than 20% of the propagules occurred as individuals; the remainder were mostly attached to the surface of airborne soil particles. Thus any action which disturbed the soil surf'ace and launched soil particles into the air, such as the operation of an agricultural implement or a gusty wind, also increased the concentration of airborne streptomycete propagules. With simulated rain, the first water drops which struck the soil surface launched both individual spores and spores attached to soil particles into the air; with time the water drops washed most propagules from the air.