Which of the following plant diseases is not caused by fungus

The plant disease that is not caused by a fungus is cassava leaf-spot. Plant diseases can be caused by different agents such as fungi, bacteria, viruses, nematodes, and environmental factors. Fungi are one of the most common causes of plant diseases. Black arm, rice blast, rice smut, and maize rust are all fungal diseases that affect different plants. For example, rice blast is a fungal disease that affects rice plants causing lesions on the leaves, while maize rust is a fungal disease that affects maize plants causing yellow-orange pustules on the leaves. On the other hand, cassava leaf-spot is caused by a bacteria, not a fungus. This disease affects cassava plants, causing brown spots on the leaves which can eventually lead to defoliation and reduced crop yield. In summary, cassava leaf-spot is the only plant disease in the given list that is not caused by a fungus but by a bacteria.