Nice looking fruits, really growing fast! Not sure what your insects are but I do not have to use surround on mine since so far I’ve been lucky with very few insect issues. If I can finish trapping my squirrels before summer my biggest pest problem will be solved. Surround works well on fruit that it easily washed off from, but unless you plan to peal your plums I might suggest bagging rather that using surround. Mainly because if they need to get soft to be ripe, washing them well enough to eat the peeling may not work well. So unless you have a lot bagging may be the best protection for plums. I do use surround on peaches and apples, and it washes off them wit warm soapy water. I actually grafted a few Flavor grenades this spring so thanks for posting Phil!
Dennis
Kent, Wa