Walnut Sphinx

An outbreak of the walnut sphinx, Amorpha juglandis, occurred in early July 2012, infesting and defoliating about 100 acres of primarily native orchards between Highway 36 and 1702, south of Gustine, Texas.

Appearance

The nocturnal tan/brown moth has a 3-inch wingspan and will mate and continue through a second generation. Larvae are pastel green with several diagonal white stripes and a prominent dorsal protrusion near the rear end.

Damage and Distribution

The walnut sphinx moth is a common leaf feeder of a wide range of trees, including hickories, and spreads from the Rockies to the Atlantic. Outbreaks that cause any pecan damage are quite rare. Reasons for this outbreak are presently unknown. Whether or not the next generation will pose any threat or spread to new areas is also unknown. We do expect that selective materials (see OMRI column of the Insecticide Search Engine results, search by pest) that are effective against fall webworm or walnut caterpillar would also effectively manage the walnut sphinx if potentially damaging densities occur.

Walnut sphinx larva (caterpillar) on pecan. Photo by Mike Berry
Walnut sphinx larva
(caterpillar) on pecan.
Photo by Mike Berry
Click to enlarge.
Walnut sphinx caterpillar (larva) in a pecan tree. Photo by Mike Berry.
Walnut sphinx caterpillar
on pecan.
Photo by Mike Berry
Click to enlarge.
Walnut sphinx pupae.  Photo by Mike Berry.
Walnut sphinx pupae
Photo by Selyna Nunez
Click to enlarge.
Walnut sphinx moth
Walnut sphinx moth
Photo by Mike Berry
Click to enlarge.

Damage to pecan tree by walnut sphinx moth. Photo by Mike Berry.
Walnut sphinx moth damage
Photo by Selyna Nunez
Click to enlarge.
Walnut sphinx damage to pecan tree. Photo by Mike Berry.
Walnut sphinx damage
to pecan tree foliage.
Photo by Selyna Nunez
Click to enlarge.
Walnut sphinx infestation of pecan.  Photo by Selyna Nunez.
Walnut sphinx
infestation on pecan.
Photo by Selyna Nunez
Click to enlarge.

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