Calla lilies are a common type of summer flower, and one of the many types of this flower that can be seen around the world. This particular type grows from bulbs, and after these bulbs wilt, they can be replanted to bloom the following year. If they fail to bloom and wilt properly, however, this can be from a variety of diseases or fungi, including a few types that can leave unsightly brown spots that cover the beautiful petals and bulbs of the calla lily flower.
One such disease that will leave your call lily flowers with brown spots is the botrytis blight. This condition creates circular or oval spots on your flowers, and these can range from orange to red or reddish brown. The spots are more frequent on older leaves, and they are created under moist conditions. The most common cause of these spots is high humidity and overexposure to moisture. If not treated, they will form fungal spores and spots that are both woolly and grayish brown.
Another common problem that can leave your calla lily leaves spotted or yellow, leaf scorch happens because of the planting conditions of the flower. This condition is non-parasitic, and is caused by neither fungi nor molds. It can occur in soils that are both low in fertility and high in acid, and will leave the tips of your leaves brown. It will also have the leaf margins develop semi-circular brown areas, but it can be treated by adjusting your soil to a pH level of between 6.5 and 7.0.
Root rot is another non-parasitic condition that will leave the parts of your calla lily turning an ugly brown color. Under this condition, the roots themselves will turn brown, and will eventually rot. The plants will turn yellow, and the leaves may see the same brown spots as you might see with leaf scorch. The plant will yield less buds, and this likely happens due to over-watering of the plants or due to poor drainage within the soil.
Fleck is a condition that will force small brown spots on your calla lily leaves, and they will appear along the veins and usually on older leaves. This is a virus that is also known as the lily symptomless virus and the cucumber mosaic virus. The flowers on the plant will end up smaller and there will be significantly fewer than normal. If this is your case, you must attempt to remove all of the plants that are infected and then control the remaining symptoms with insecticide.