Look up and down the trunk of the pines. If you see spots with sap coming out, sort of like someone stuck chewing gum on the trunk, if so, you may have pine beetles. Also look for saw dust on the bark and around the trunks.
This time of year, squerriels will be up in the pines cutting the pine cones, so dont confuse the mess under the tree from the squerriels feeding.
John

i don't see any sap nor sawdust. i think it is the drought.
thanks.

My pines are shedding also but I dont have any brown spots. Anyway I hope its not beatles. Ive had to cut down four pines in the last couple years because of them.
John