rust fungus is one of my all-time most frustrating garden problems. I buy gladioli every year, and every year I get rid of them once the rust starts. On hollyhocks its the sign of the end, as it can eventually become lethal to the plant. Watering from above, and watering in the evening, both can cause rust to develop.
So, how do we treat it? Firstly, recognize the symptoms and causes. Excessive moisture and humidity increase the chance of rust infections, so avoid overhead watering and over-watering, which favor the germination and spread of fungal spores. Orange-brown spots on foliage and stems. Leaves may die and drop from plants, weakening the plant and resulting in death in extreme cases.
On Hollyhock ( we will talk about gladi's further down the post ) Remove infected leaves from plants as soon as the fungus is seen. In winter, when the hollyhock dies down, clear away any infected leaves as they will harbor the fungal infection. Remember, bin don't compost! make sure to water from below with a slow running hose, keep a space around the plant for air and remove dead foliage.
if you are finding its not working, your next step is to look at treating them with systemic fungicides. A home made fungicide can be made using two aspirin in a liter of water, dissolve then spray on the affected plant every two weeks.
Another option is Neem oil, which is an organic fungicide that is derived from a broadleaf evergreen plant called neem tree (Azadirachta indica). Use a ready-to-use neem oil product as a foliar spray once every seven days until the disease is under control. Continue applying at 14-day intervals to keep the disease from returning. Follow any additional directions on the label. Remember that Neem is toxic so wear masks and gloves and don't spray on a windy day. PLEASE remember that neem is also a natural pesticide and WILL kill bees and butterflies and all living bugs. never spray a plant with buds as it will damage the flowers and kill the insects that feed on it once open.
Simply spray your solution onto the stem areas and the underside of your plant's leaves--which is where the rust typically begins, until every surface is thoroughly coated. Continue treatment regularly.
those gorgeous spears of blooms that brighten any garden. the gladioli is a welcome sight every summer, but unfortunately, the new hybrids are prone to rust. A lot of people think there's nothing you can do to treat it but there's a few options. If your gladioli show signs of rust you may need to spray with an organic copper spray. kiwicare has a product called Organic Super Sulphur. Spray in the evening to avoid harming beneficial insects and avoid watering the leaves of your plants. try pruning the infected leaves off and binning them. Neem oil is going to be the most effective oil for controlling fungal infections. It is a good choice for mild to moderate powdery mildew infections too. one issue with using oils is they are no good in hot weather as they cause the plant to burn.