yellowing needles on new JBP candle?

I went out this morning to see that some of the new candles on my black pine or yellowing and when I gave a slight pull they came right off? Any ideas, as I've never had this before. Anything I can do or should I be worried?

It looks like damage from the pine tip moth.  Scroll down a little at this link and you'll see a photo that looks like yours:  https://nebaribonsai.wordpress.com/category/evergreen/japanese-black-pines/corkbark-black-pines/

Additional information is here: http://www.forestpests.org/nursery/pinetipmoths.html

You think a systematic insecticide should work?

If you break off one of the yellowed candles and it is hollow and has a larva inside, this is pine tip moth.

Agree with all.  You have definite Pine Tip Moth infestation.
Those destructive critters run rampant here in the Tidewater Virginia region, once early spring sets in.
Beyer systemic will work - but, it takes up to a month after application for it to get up into the new growth foliage, if applied during the relatively cold early spring time period. This may be too late to prevent further attacks on your pine Bonsai by the moths.

For the Tidewater Virginia area...  You will get best results if you spray your pines with Malathion in late March/Early April to prevent Pine Tip Moth attacks.  Follow up this treatment with a re-application in early to mid-June.  Beware of using systemics in the hot summer months!
We have lost older/established Bonsai trees here when systemics are applied during hot summer months, when our Pines are somewhat stressed from high temps.  Applying systemic fungicide and losing the beneficial Mychorrhizia fungus they have depended on at the worst possible time, is a good way to kill a nice Pine Bonsai.