Question

Which one of the following is not a fungal disease?
A. Rust of wheat
B. Smart of bajra
C. Black rot of crucifers
D. Red rot of sugarcane

Answer 1

Hint: Fungi, which has the yeasts, rusts, smuts, mildews, molds, and mushrooms. There are many fungus-like organisms, including slime molds and oomycetes (water molds), that don't belong to kingdom Fungi but are often called fungi.

Complete answer:
To answer this question we need to discuss the above mentioned options in detail.
Plant pathology is that the scientific study of diseases in plants caused by pathogens (infectious organisms) and environmental conditions (physiological factors).Organisms that cause disease include fungi, oomycetes, bacteria, viruses, viroids, virus-like organisms, phytoplasmas, protozoa, nematodes and parasitic plants. Infectious plant diseases are caused by bacteria, fungi, or viruses and may point severity from mild leaf or fruit damage to death.

Leaf rust is a fungal disease that affects wheat, barley and rye stems, leaves and grains. In temperate zones it's destructive on winter wheat because the pathogen overwinters. Infections can initiate to twenty yield loss, which is exacerbated by dying leaves, which fertilize the fungus. The pathogen is Puccinia rust. Rust causes "stem or black rust", P. triticina causes "leaf or brown rust", and P. striiformis causes "strip or yellow rust". It's the foremost prevalent of all the rust diseases, occurring in most wheat growing regions.

Smut of bajra (pearl millet) (Pennisetum glaucum), caused by Tolyposporium penicillariae, is a very important and widespread disease. It causes direct loss of grain by replacing them with smut sori, and yield losses of up to 30% are reported. In recent years the disease has become more important on commercial F1 hybrids in India and on exotic early-maturing cultivars in countries of Africa. The text describes and illustrates geographical distribution, disease symptoms, disease cycle, morphology of the causal fungus, and disease management methods. Various control measures are presented, with emphasis on host-plant resistance, including screening methods and use of resistance.

Black rot, caused by the bacterium Xanthomonas campestris, is taken into account the foremost important and most destructive disease of crucifers, infecting all cultivated styles of brassicas worldwide. This disease is difficult for growers to manage and is taken into account the foremost serious disease of crucifer crops worldwide.

Red rot may be a very serious disease of sugarcane. The symptom of the disease is the reddening of the interior internodal tissues with crossbars of white patches within the reddened area. This red colour is caused by a dye which is secreted by the host and is antagonistic to the red rot fungus. Infection takes place through mother setts, holes within the nodal regions, the cut ends of the seed canes and other injuries. The disease causes damage to the sugarcane drop mainly by reducing the crop stands and by reducing the sucrose content of the cane juice.

Therefore, the correct answer is c, black rot of crucifers.

Note: Control of plant diseases is crucial for production of food. Plants in both natural and cultivated populations carry inherent disease resistance, but there are numerous examples of devastating plant disease like rice blast, soybean cyst nematode, and citrus canker.

Disease control is achieved by use of plants that have been bred for good resistance to many diseases, and by plant cultivation approaches such as crop rotation, use of pathogen-free seed, appropriate planting date and plant density, control of field moisture, and pesticide use. Continuing advances in the science of plant pathology are needed to improve disease control.