Chlorosis & Necrosis:

Chlorosis:

1. It is symptom of plant disease where the chlorophyll in green parts of host is destroyed due to viral infection.

2. It results in appearance of yellow spots.

3. Yellowish spots in green tissue give a mosaic pattern.

Necrosis:

1. It is also a symptom of plant disease where death of host tissue occurs due to viral  infection.

2. Drying of dead tissues results in appearance of brown spots called necrotic spots.

3. Mosaic patter not ever appears.