Dead mycelium of Penicillium chrysogenum protects transplanted cotton plants agains fungal wilts in a saline field

Abstract

Previous studies have shown that the dead mycelium of Penicillium chrysogenum at 900-1,500 kg ha–1 effectively  controlled Fusarium and Verticillium wilt of cotton. Our objective was to determine if the dead mycelium is also  effective at lower rates under a cotton seedling transplanting system. Columned soil blocks (500 g each), made of  fertile soil alone in the first experiment, and both soil and dead mycelium at varying rates in the second experiment,  were sown with cotton seeds in 2006 and 2007. Seedlings in the mycelium-free blocks were drenched with aqueous  extract of the dead mycelium after full emergence, and then transplanted to a saline field. The disease severity of  Fusarium oxysporum f.sp vasinfectum and Verticillium dahliae, leaf chlorophyll and malondialdehyde concentrations,  leaf photosynthetic rate and lint yield of the transplanted plants were determined. The aqueous extract at a rate of 1  to 5% provided 18.6 to 25.6% protection against Fusarium wilt but not against Verticillium wilt. Lint yield was slightly  increased with the aqueous extract in 2006, but not in 2007. The incorporation of the dead mycelium to soil blocks  before sowing was effective in controlling both the Fusarium and Verticillium wilts of cotton. Dead mycelium applied  at 1 to 3% (w/w) provided 26-30% protection against Fusarium wilt and 48-50% protection against Verticillium wilt,  and increased lint yield by 13-14%. Such incorporation also delayed leaf senescence as indicated by the increased leaf  photosynthetic rate and chlorophyll content, and reduced malondialdehyde concentrations. Incorporation of the dead  mycelium of P. chrysogenum into soil blocks at a relatively lower rate (270 kg ha–1) would be an effective application  mode for wilt control in sustainable cotton production.