Gladiolus Fungus Disease
During my planting season, fog & frost spoil plants by making them fall sick with Botrytis as told by my neighbor. I usually notice parts burning after foggy day or night. Later plant completely turns brown, stems rot & break. As far as I experienced, frost is not as big a problem as the fog. I use fungicide but results in vain. What precaution or measures I can adopt before fog & frost season begins to prevent, cure or at least reduce the number of plants falling sick? Thanks.
I am sending you an article that describes the common diseases of gladiolus and their treatment. As you can see, there are quite a few. http://www.extension.umn.edu/garden/yard-garden/flowers/gladiolus-diseases/index.html
The first thing is to identify what illness your flowers have. The best way to do this is to take some samples to the nearest Extension Service (if you're in the US, this link will help you locate https://www.gardeningknowhow.com/extension-search/ ) or if you are somewhere else, try a university or landscape expert.
Treatment for any disease will involve treating the soil, the corms, and the foliage; proper culture in terms of light, water, and soil factors; and using the best gladiolus variety for your area. If you have badly infected soil, you might need to try a different kind of plant.
The problem is not caused by cold and damp conditions, but by an infectious organism that takes advantage of plants that are stressed by, probably, a number of conditions, only one of which is climate.