Pythium and use of biocontrols: These products are protective and suppressive; they are not curative and should be applied preventively

摘要

Damping-off and root rot caused by Pythium spp. (species) is one of the most commonly occurring diseases in greenhouse crops. Most Pythium spp. principally infect young, succulent tissues and therefore infection is usually restricted to feeder roots or root tips of older plants. Pythium survives best when other micro-organisms are either not present or have reduced activity such as in virgin rockwool or other soilless media. Pythium spp. can survive by growing saprophytically on dead tissue, or by zoospores (tiny swimming structures) that can persist at least seven days in moist media, by means called sporangia, which can survive for several weeks, or by thick-walled oospores that can remain live for up to several years.