Exposure to bioaerosols during the growth season of tomatoes in an organic greenhouse using supresivit (Trichoderma harzianum) and Mycostop (Streptomyces griseoviridis)

In working environments, especially in confined spaces likegreenhouses, elevated concentrations of airborne microorganismsmay become a problem for workers' health. Additionally, theuse of microbial pest control agents (MPCAs) may increase exposureto microorganisms. The aim of this study was to investigatetomato growers' exposure to naturally occurring bioaerosol components[dust, bacteria, fungi, actinomycetes, (1" src="/math/rarr.gif" border=03)-ß-D-glucans,and endotoxin] and MPCAs applied by drip irrigation. Airbornedust was collected with filter samplers and analyzed for microorganismsby plate counts and total counts using a microscope. Analysisof (1" src="/math/rarr.gif" border=03)-ß-D-glucan and endotoxin content was performedby kinetic, chromatic Limulus amoebocyte lysate tests. The fungalstrain (Trichoderma harzianum) from the biocontrol product Supresivitwas identified by PCR analysis. Measurements were performedon the day of drip irrigation and 1 week, 1 month, and 3 monthsafter the irrigation. T. harzianum from Supresivit could bedetected only on the day of treatment. Streptomyces griseoviridis,an applied MPCA, was not detected in the air during this investigation.We found that bioaerosol exposure increases during the growthseason and that exposure to fungi, bacteria, and endotoxin canreach levels during the harvest period that may cause respiratorysymptoms in growers. The collected data indicate that MPCAsapplied by drip irrigation do not become airborne later in theseason.