The broad spectrum fungicide mancozeb was applied to monocultured
sugarcane soils affected by the growth constraint known as
sugarcane yield decline. The constraint is associated with the long-term
monoculture of sugarcane and has been shown to decrease
sugarcane growth by 20% in commercial crops in Queensland. The fungicide
was
shown to decrease root colonization by soil fungi,
particularly dematiaceous sterile fungi. Higher doses of mancozeb (up to
400 mg kg−1) sometimes led to increased populations
of Penicillium spp. The fungicide greatly improved plant growth
and root health when applied at doses of 100 mg kg−1
and above. Results suggest that the role of dematiaceous sterile fungi
in
sugarcane yield decline should be further examined.