Pg. Zhang et al., INOCULUM CONCENTRATION AND TIME OF APPLICATION OF GLIOCLADIUM-ROSEUM IN RELATION TO BIOCONTROL OF BOTRYTIS-CINEREA IN BLACK SPRUCE SEEDLINGS, Canadian journal of forest research, 26(3), 1996, pp. 360-367
Inoculum concentration and time of application of Gliocladium roseum B
ainier were examined in relation to sporulation of Botrytis cinerea Pe
rs.:Fr. in container-grown seedlings of black spruce (Picea mariana (M
ill.) BSP) in greenhouses. Gliocladium roseum concentrations ranging f
rom 10(2) to 10(8) conidia/mL water plus surfactant, applied four rime
s at 2- to 4-week intervals starting when the seedling canopies closed
, increasingly suppressed the proportion of seedlings with sporulation
of B. cinerea (YI) during early and midphases of epidemics, and the p
roportion of shoot length with sporulation of the pathogen (YS) throug
hout the epidemics. Concentrations of 10(6) and 10(8) conidia/mL suppr
essed YI and YS as or more effectively than did chlorothalonil (1.4 g
active ingredient/L water) applied at the same times. One application
of G. roseum (10(6) conidia/ml) when the seedling canopies were closin
g suppressed YS as effectively as did programs of two to six applicati
ons of the antagonist, or six of chlorothalonil, all at 1- and 2-week
intervals beginning at canopy closure. The various programs generally
did not affect YI. Logistic and Gompertz regression models were develo
ped that adequately described YI and YS as functions of inoculum conce
ntration and (or) time. It is concluded that G. roseum has potential a
s a biological control agent against B. cinerea in production systems
of black spruce seedlings.