Observations on the vapour phase activity of some foliage fungicides

摘要: SUMMARY By means of a Botrytis fabae/Vicia faba bio-assay technique it has been demonstrated that phenyl mercury chloride, maneb, mancozeb, dichlo-fluanid and oxythioquinox protect areas leaf beyond the visible limits fungicide deposits. The evidence suggests extended protection are due to release fungicidal vapours. For given dose mancozeb area was related number conidia B. fabae dusted on leaves for inoculum density with increasing applied in standard drop sizes. When same volumes water, producing widening deposit, also increased. Fungicide deposits aged up 4 weeks continued toxic vapours. Contact between fungicides or spores not necessary demonstration phenomenon since vapours diffused from glass inhibited germination water droplets placed at distance source. separating inhibition increased dose. dose, decreased distances spores. test fungi other than fabae. The practical implications these observations examined light vapour phase can occur incubated large cabinets; pre-incubated unsaturated humidities; moving stream air.