Although fungi have cell walls, the chemical composition of the wall material is often drastically different chemically from the cellulose wall material we find in higher plants. Many of the fungi which attack squash reproduce by developing and releasing large numbers of spores. Others require splashing rain or irrigation for dispersal. Some fungi, particularly those that cause root and stem diseases, have specialized spores that can survive many years in the soil in the absence of squash. Bacteria are smaller than fungi and are not at all plant-like.
All bacteria are just one cell, and they lack chlorophyll.
The ones that cause plant disease do not form spores. The major type of reproduction for plant pathogenic bacteria is by simple cell division. Bacteria never enter plants directly. They must have a wound or a natural opening to get inside a potential host plant. There are no cellular structures.