A Pazazz apple tree on a Geneva 935 rootstock shows signs of stress during a rootstock trial tour last fall in a Brewster, Washington, orchard. Researchers and growers have noticed mysterious tree decline when certain varieties and rootstocks are married. Pazazz, Royal Red Honeycrisp and Firestorm Honeycrisp on G.935 are among the problematic pairings. &lt;b&gt;(Ross Courtney/Good Fruit Grower) &lt;/b&gt;