Sarah wrote at 2016-01-06 17:19:09
I'd like to add some more information to this discussion. Karen doesn't mention where she lives but I'm assuming it is SoCal, as red apple is prevalent there. This isn't a problem with not-enough watering or low temperature, as the problem has also been manifesting since mid- to late-summer, 2015. Temps are not below the mid 60s summertime here, and overwatering not the problem, we are restricted due to the drought. It appears to be an airborne vector, be it some form of fungus or aerosol, something sprayed over a large region. It is not spread via watering. I live in an area of SoCal/San Bernardino County where almost all the red apple is dying off in our neighborhood, particularly in the exposed areas, but where the plant is under pine trees or growth creating some sheltering canopy, those particular plants are growing well and seem unaffected. We've also noticed that some of the shelter-providing oaks show what appears to be a subtle mottling of the leaves as if they are also suffering some of the effects of this "disease". Older red apple plants seem to be strong enough to produce new growth near the soil, but runners and new plants are succumbing. I wish I had more information to offer, but I am also looking for an answer and finding that more description of the problem needs to be offered also, to help people search. This is not a simple sporadic die-off.
Plant diseases, landscaping, tropical plants, roses, herbs, plant care, grafting, horticulture, plant identification, anything about plants I can likely answer.
35 years experience in various plant businesses, 1984 Certified Texas Master Gardener.
Organizations Master Gardener Association of Texas charter member
Publications none as of yet, but I have a plant q&a book I am in process of submitting.
Education/Credentials Magna cum laude graduate of Texas A&M, 1978
Awards and Honors Plant growing awards, highest grade for Texas Master Gardener graduates.
Past/Present Clients Past member of Allexperts.com and was very highly rated. Owned landscape company in the past, Almost Paradise, and was very successful despite little equipment, no help, and no advertising. Lived well for two years until 9/11.