It is the fungus named ophiostoma Novo- ulmi that targets American elm and siberrian elm. In the elm infected with these diseases, the movement of water is blocked leading to death of these trees.
There are several ways that shows the trees are infected with these diseases. Some of the noticeable symptoms are:
These symptoms first appear to the areas where this fungus has entered like either the lower crown or the particular branch. This symptom are usually observed at the growing time of the season and kills the tree within a week and even it may take a year.
This disease is spread to other uninfected trees as well. When the elm bark beetle comes out from the dead elm tree, it reaches to the other nearby trees and infects them. This infection is due to the fungus that is carried by bark beetle from infected dead tree to the healthy elm tree. Beside this, if the root of infected elm comes in contact with the root of healthy elm the diseases easily get transferred.
There are several ways of controlling this diseases form spreading that prevents infected tree from affecting the other. The safety measures include:
Kudzu is a plant that is native to Japan and china. It has many advantages and also there are certain disadvantages of planting kudzu. Though the climate of Japan supported the proper growth of kudzu and helped in control for erosion but when it was introduced or bought to southeast U.S, it became a pest. Over a period when it was left unchecked, kudzu blocked sunlight and grew over almost any fixed object whether its house, vehicle, bran, on roadside and many more places. Presently, it have becomes difficult to control this pest and no result for its control have been yet found out. The temporary measured include grazing of livestock and applying some herbicides, but with the change in season it spreads widely and has become a problem.
So, kudzu has lots of advantages on health but once introduced can be difficult to control and manage.
It is the fungal disease that affects potatoes destroying its tuber. This disease is caused due to phytophthora infestans fungus. This fungus gets into in the plant or lands on the roots of potatoes though the airborne spores. They spread once they find the climate and environment suitable.
Symptoms: some of the changes that can be noticed in the plant once they are infected with this disease are:
Preventive measures: we can adopt some technique or ways to protect the plant and keep it free from this disease:
Beside potatoes these diseases also attack tomatoes plant thus, infecting them. Therefore, it is important to timely abolish this by proper monitoring of plant and use of some improved technique.
This disease is caused by the virus named variola virus and gets transmitted form one person to the other by direct contact.
Symptoms: the symptoms of this disease include:
Prevention: the only way to prevent this disease is through vaccination. The vaccines named Dryvax; vaccinia etc should be administered to the infected person timely.
Presently, this disease is almost eradicated from every country and the world due to timely availability of the vaccines and some of the advanced technology that have helped in delivery of vaccine in every corner of the world.