Botrytis cinerea에 의한 백일홍 잿빛곰팡이병

Abstract

2003년 4월 경남농업기술원 유리온실과 농가 육묘장에서 Botrytis cinerea에 의한 백일홍 잿빛곰팡이병이 발생하였다. 병징은 잎과 줄기에 발생하여 병든 부분이 수침상으로 물러지고 썩으면서 병반부위에 회색의 곰팡이가 많이 생기고, 심할 경우 감염된 부위는 결국 말라 죽는다. 분생포자는 무색, 단포자이며 난형 또는 타원형으로 크기는 5<TEX>${\sim}$</TEX>16<TEX>${\times}$</TEX>4<TEX>${\sim}$</TEX>8 <TEX>${\mu}m$</TEX>였고, 분생자경 위에 분생포자가 아주 많이 형성되었다. 분생포자경은 갈색으로 격막이 있고, 폭은 12<TEX>${\sim}$</TEX>28 <TEX>${\mu}m$</TEX>였다. 균핵의 모양은 납작하거나 부정형이고 색깔은 검은색이었다. 균사생육과 균핵형성 적온은 <TEX>$20^{\circ}C$</TEX>였다. 병반에서 분리한 병원균은 Botrytis cinerea Persoon: Fries에 의한 백일홍 잿빛곰팡이병으로 동정되었다. In April of 2003, the gray mold disease caused by Botrytis cinerea was occured in zinnia seedlings grown in greenhouse at Gyeongsangnam-do Agricultural Research and Extension Services, and farmer's nursery. The symptoms of infected plants were started with water-soaking lesions in flower bud, leaves and stems. The lesions gradually expanded and infected plants became withered and discolored to gray or dark from the tip. The conidia and mycelia of the pathogen were appeared on flowers, leaves and stem. The conidia were gray, 1-celled, mostly ellipsoid or ovoid in shape and were 5<TEX>${\sim}$</TEX>16 <TEX>${\times}$</TEX> 4<TEX>${\sim}$</TEX>8 <TEX>${\mu}m$</TEX> in size. Conidiophores were 12<TEX>${\sim}$</TEX>28 <TEX>${\mu}m$</TEX> in size. The pathogenic fungi formed sclerotia abundantly on potato dextrose agar. The optimum temperature for sclerotial formation was <TEX>$20^{\circ}C$</TEX>. Pathogenicity of the causal organism was proved according to Koch's postulate. The causal organism was identified as Botrytis cinerea Persoon: Fries based on mycological characteristics. This is the first report on gray mold of Zinnia elegans caused by Botrytis cinerea in Korea.