Xtremehorticulture

Skeletonizer Damage on Tecoma Can Look Like Drought

Q. From a distance I thought my Yellow Bells and Orange
Bells shrubs weren’t getting enough water because the leaves started turning
brown. But when I looked closer, I’m wondering if the brown leaves are because
of a fungus on the leaves.  Any thoughts?

A. Look at the leaves of your Tecoma, a.k.a. Yellow
or Orange Bells, more closely and I think you will see that the surface
of the leaf has been eaten or “skeletonized”. This chewing damage causes the
leaves to turn brown; they become brown faster when it’s hot out. At a distance
you see the leaves of your Tecoma turning brown and it may look like
drought.  Upon closer inspection, you get
more detail and can see the insect damage to the leaves and not a disease.
Skeletonizer damage on Tecoma spp. Yellow or Orange bells
            This
shrub is native to the Sonoran and Chihuahua and deserts of the Southwest, all
through central and even the northern parts of South America, but not the
Mojave Desert where it needs slightly more water and warmer winter
temperatures. Tecoma and this skeletonizer coexist together. The skeletonizer
is the younger stages of a moth. It’s not clear if this insect will survive the
low temperatures of our winter or not. If it does, as more Tecoma are
planted, we may see more of this insect damage in future years.
Orange bells

            This
insect damage is common to Tecoma in warmer parts of the Southwest. It’s
feeding damage by the young, a.k.a. larvae, of a moth given the common name Tecoma
Leaf Tier Skeletonizer
. This damage is like the skeletonizer damage we see on
grapes but caused by the young of a different moth.
            Right
now, this insect doesn’t usually cause enough damage to warrant spraying an
insecticide. Just pull off leaves when damage appears and drop them on the
ground. If the damage gets worse in future years, then spraying might be
warranted.
            The
pesticides of choice are “natural” insecticides called Bt and Spinosad. Apply
these sprays just before you anticipate damage or at the first sign of damage.
Bt and Spinosad products will kill the larvae of any moth or butterfly, whether
it’s good or bad one so be careful.
            Spinosad
can be hard on honeybees so don’t spray plants that are flowering and spray at
sunup. If you have no choice when to spray, and the plant has flowers, remove
them and more flowers will be produced later.

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