Question

Who reported that curly top virus spread through a plant via the food conducting tissue or phloem tissue?

Answer 1

Hint: When the leaves of crops thicken and curl, plant growth is stunted and they eventually die,the cause is curly top virus. This causes plants to become smaller in size, shriveled leaves and twisted shape. It is caused due to curto viruses.

Complete answer: Let us first know about the virus
Curly top virus is one the most contagious viruses that affect plant growth and development. The viral disease causes plants to become smaller in size, twisted and shriveled leaves. It is characterised by stunting of the plant and deformation of leaves and fruit. The petioles and blades of the leaves curl, twist, and become discolored.
The disease was noticed in California in 1890, with severe losses reported from the sugar beet industry. In 1900, it was noted throughout the western states in the places where sugar beets were grown.
The disease was found to be spread through phloem tissues by the scientists. The exudate from the cut surface of diseased beets closely resembles the natural exudate from the petioles in viscosity, hydrogen- ion concentration,virus content,and total solids. The naturally occuring exudate was derived from the phloem and the content of the exudate was made up of the content of the phloem tissue except for a certain amount of unavoidable contamination from the injured cells of other tissues mainly parenchymatous in nature. It has been used extensively in all experiments in which only small quantities of virus containing liquid were required.

Dr. Esau's plant anatomy published in 1954 reported that the curly top virus spread through a plant via the food conducting or phloem tissue.

Note: The determination of properties of curly top virus is somewhat more difficult than similar determinants of other viruses as the percentage of infection is so low that we can infer whether the plant is infected with the virus or not. Experimental work on this virus led to the development of a method for artificially feeding the beet leafhoppers. In this leafhoppers were used to transfer the disease to a susceptible tissue that was hammering the growth in the plant.