My maikai has streaks and spots, too - first I roasted it in the sun, then we had 2' of rain a month for 3 months - so I think that is the cause of my streaking.
You can send a sample to Critter Creek Labs - they will e-mail a results file to you within a few days. Very reasonable price.
Critter Creek Laboratory
The site also has some general information on viruses. BC Maikai is a fast-growing plant that is divided and swapped a lot in our society, so that is kind of a 'caution' light.
Regards - Nancy