Ecology, Environment and Conservation Paper

BIOLOGICAL CONTROL OF MAJOR SOIL- ORNE DISEASES OF CARNATION USING FUNGAL ANTAGONISTS, PARTICULARLY TRICHODERMA SPECIES

Sunita S. Chandel and Nandita Pathanie

Abstract

Carnation is susceptible to many diseases. of which soil borne are of major concern.Wilt, root rot, stem rot and basal rot are considered to be the most economically important diseases which occur during summer to rainy months in moderate to severe form.An attempt was made in the present study to control these diseases through application of well known biocontrol agents. In total, six different species of Trichoderma viz. T harzianum, T viride, I hamatum,. virens,T. koningii and T. Iongibrachiaturn were assessed both in vitro and in vivo for their antagonistic activity against above mentioned soil-borne disease causing pathogens. Trichoderma virens suppressed maximum growth of Fusarium oxysporum f. sp. dianthi in dual culture technique while T harzianum and T viride were found most effective in inhibiting the mycelial growth of Phytophthora nicotianae var. parasitic° and Sclerotium rolfsii respectively. However, per cent mycelial reduction in Rhizoc-tonia solani was observed highest with T. harzianum followed by T vi ride. In pot culture experiment, T. harzianurn gave excellent control of wilt, root and basal rot diseases by giving maximum disease reduction when applied twice as soil drench whereas stem rot incited by Rhizoctonia solani was minimized to great extent with addition of T hamatum in soil a week ahead of transplantation of cuttings and 45 days after establishment of cuttings.