Japanese Maple Die Back & White Stuff On Pyracantha

Question:

We have a six-year-old Coral Bark Japanese Maple. Last year, a few of the smaller branches turned black, and we pruned them off.  Now one of the three main branches is doing the same thing, and the leaves are shriveling. The shape of the plant will be ruined if we remove it. What should we be doing?    

Answer:

  •  It’s never good news when the stems of a Japanese Maple turn black.
  • The black coloration is a primary indicator of a vascular disease called Verticillium Wilt. Verticillium Wilt is a soil-borne fungal disease that’s common in our Bay Area soils. When the infected stems are cut, you’ll find black streaking through the tissue.
    • It attacks a wide range of ornamental and herbaceous plants including, tomatoes, peppers, roses, Pistache and Camphor trees.
    • The fungus works its way up the plant from the roots disrupting the vascular tissue that is responsible for transporting water and nutrients throughout the plant.
  •  Unfortunately, we have no controls for this problem. The disease does attack without warning.
    • Our poorly draining, heavy clay soil and excessive summer watering doesn’t help. It’s particularly frustrating when Verticillium Wilt attacks established and thriving ornamentals.
  •  With tomatoes and other vegetables, we can plant resistant varieties, but that’s not the case with Japanese Maples
  • . I’d removed the infected limb because it is not going to recover and encourage the new growth by feeding it a Japanese Maple Fertilizer. 
  • A replacement branch can be selected from the new growth.
  • When the temperatures are over 80 degrees, I'd water Japanese Maples weekly. If they are in a shady location, they can go longer in between watering, every ten to fourteen days.

Question:

We have a very large Pyracantha that’s covered with white cottony sticky clumps. My neighbor showed me the little bug that was inside the white stuff.  Can you please direct me on‹ how I can get rid of these bugs?

Answer:

  • The bug is called Wooly Apple Aphid.
  • They are one of many species of Aphids, but this one is particularly unique as it can be found on woody plant parts as well as on the new growth.  It can also attack at the crown or base of plants and along with the surface roots.
  • Wooly Apple Aphid is common on Pyracantha, Crabapples, Apples, Cotoneaster and other plants.
  • You will need to pick off the worst of the curly leaves and treat the rest of the plant with Insecticidal Soap or Neem Oil.  Several applications a week apart are necessary and be sure you soak the limbs, trunk, and base of the plant.