1 Background and significance of plant diseases

Transcript

Hello, everybody this is the first lecture of this course. We need to understand why this course or why this topic is important. This topic is important because every year around 10% of the total crop produce is lost due to diseases and if we just see that sometimes it may get extended up to 30% of disease losses. So, to minimize this loss which is a great loss to the whole world we need to understand the principles of plant disease and managing these diseases so, it is very important to understand. The history of this particular branch of science and history shows that branch Plant Pathology developed because of the Irish famine. So, the Irish famine took place in the year 1845 to 1851 and during this period there was elimination of around 1million people from Ireland either due to death or due to migration to other countries. So, it shows the significance of plant disease management for this point of view. And if we just look, why this particular things happened? Why so many people died? It was because there was no idea what led to this particular disease. Systematic studies on this disease has understood that it is due to a fungal agent that caused this disease which later named as late blight of potato it was caused by a fungus now it is identified to be Phytophthora infestans. So, if you just look into the history we will see that a series of such famines took place in the past that led us to seriously study this subject of plant pathology and managing this disease in a sustainable manner in India. Also, if we just look into the history in 1943 and 44 this is the period where a famine took place in Bengal and it was due to a disease that occurred in rice known as brownleaf spot. And this particular disease has also led to death of around 2.1 million people in at the Bengal area. So, even now country like India is not spared from this famine.

So, plant pathogens are that is why it’s so important that we need to tackle this pathogens in a sustainable manner to minimize this loss and to minimize the death of people. If we just look into the actual and potential loss of the crops by the fungal diseases we can just see that wheat, rice, maize, potatoes and cotton all these diseases occurs in all these plants but the potentiality of damaging by diseases to these plants are much more than we are facing. Currently, it is due to the favorable environmental situation or the most in certain favorable conditions when it occurs then the devastation may be even greater than what we are facing in the current days.

Globally, the two most important fungal pathogens has been rated to be most serious – one is the rice blast pathogen i.e Magnaporthe oryzae and the other one is wheat rust. These two pathogens can cause severe damage because these two are the staple float. Globally and once these particular two crops are affected by these two particular pathogens then, we can see that we may again face hunger globally. So, we need to tackle these problems. So potato blight, rice blast, wheat rust, corn smut and soybean rust if we just consider these five diseases then we can see that if we are able to minimize the losses due to these pathogens. We may be able to feed several thousands more people in today’s world because of the losses between these particular five crops. So, we have a total estimate of around 600 to 4,000 additional million people could be fed if we are able to tackle these particular pathogens in this five crops alone. So it again indicates it’s again shows that how important for us to manage these pathogens so that we can occur minimal loss to the agricultural produce and that is how we can save billions of dollars globally and we can extend our total produce to those people who are still deprived of food so far. So we can now understand the significance and background of the concept of this sustainable management of plant diseases because it will lead to either manage these pathogens significantly so, that we can extend our produce to a greater amount from the existing ratio and we can feed to the or we can provide more food security to the world if we are able to manage these pathogens sustainably.

Thank you.