I only had luck with fresh seeds that I surface sterilized with 3% Bleach ( OR a 1.5% Ca[CLO-]2 ) for about 10 min and had sown in well draining sterilized soil. Also, only the ones I had kept in 90 to 100 % humidity survived. Leave them that way till they are large enough to harden off to less desirable climate for them. I never used any on them, but an environmentally friendly fungicide may also help you.