The two of you have performed a limited experiment where your site was the control. Of course your soil may be different as may be water management but it's interesting that he got much more vigorous growth. New apples are usually transplanted 2-year trees that suffer root damage when being dug up and therefore don't tend to respond the first season to fertilizer applications although they may grow faster the second season as a result of applications the first. The only consistent advice I read about fertilizing these trees is don't put quick release fertilizers in the planting hole. I wouldn't describe a rapidly growing new tree as "running amuck" unless maybe it was my neighbors tree and was planted at the same time as my runted one. Then I'd probably do exactly as the neighbor did to try to duplicate those results. If it runs amuck then you should pinch prune it to get it running right. Anyway, I suggest the MG if that's the fertilizer of choice, although any quick release nitrogen would likely have the same affect at same rates.

Most likely woolly apple aphids. Some kinds of apples are affected more often, and worse, than others. The glitch in managing them is that part of the population is on the root system and impossible to eradicate. If you have any sort of warranty from the seller, I'd contact them immediately to tell (& perhaps show images) then ask for a rebate. I'd be leery of getting a different apple tree from the same source -- very possible all their stock is infested. Here's a blurb from the Univ of CA http://www.ipm.ucdavis.edu/PMG/GARDEN/FRUIT/PESTS/woolyapaph.html Here is a link that might be useful: woolly apple aphids

I'm not an expert, so you will have to google it unless someone else chimes in. But those are aerial burr knots which m111 are prone to grow. My trees are 10 years old and they have outgrown them, I.e., it has not been an issue. No pun intended. I did have to battle knot borers but the latex paint wash at the base helped. It is less of an issue now as the trunks are bigger

thanks for the reply. After searching a bit, it seems like that is what it is. doesn't look like there's ton to be done for it, at least now that it's broken dormancy. I may have to cut it back, and cut some of those out over the winter. Looks like I can cut one of those branches off, stick in the ground, and a new tree will grow. I am wondering now if the whole entire tree is rootstock, and whatever the original graft was is gone. weird. I have no idea what sort of apple tree it is. prior homeowner had no idea, but the neighbor says they're very tasty and the tree is productive. I think I'll give it this year, then try to figure out what to do in the fall. thanks again.