Erythrina Gall Wasp
(Quadrastichus erythrinae Kim)
The Erythrina Gall Wasp is an exotic pest of the wiliwili tree (Erythrina variegata). Common tree names include tigers claw, Indian coral tree and wiliwili-haole. It was first discovered in Hawaii in 2005. The developing EGW larvae induces galls in tender leaf and stem tissue. Unchecked infestations cause leaf deformation, reduction in growth, defoliation and tree death.
PHOTOS:
A: Enlarged adult female erythrina gall wasp.
B: Severe erythrina gall wasp damage.
C: Erythrina gall wasp pupae inside the gall.
D: Erythrina gall wasp damage on “Tall Erythrina”.
WHAT TO DO:
WHEN TO DO IT:
Research into the efficacy of Arborjet’s product IMA-jet (imidacloprid) and another trunk injectable insecticide is currently being conducted by the USFS and the University of Hawaii.
Arborjet recommends a trunk Micro-infusionTM of IMA-jet (imidacloprid) insecticide using the Tree I.V. system and #4 Arborplugs using the Arborplug Technology.
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Generally, the best seasons for micro-infusion are fall and spring. Uptake occurs when trees are transpiring. The environmental conditions that favor uptake are moderate temperatures, adequate soil moisture, and high humidity. Soil temperature should be above 40 degrees for micro-infusion. Tree health will influence uptake time. Generally, hot weather or dry soil conditions will result in a reduced rate of uptake. If treating trees in the summer, micro-infuse in the morning for the quickest uptake. A dying tree is a poor candidate for treatment. It is the responsibility of the arborist or tree custodian to assess tree health and its potential for recovery before undertaking treatment.
Micro-infusion time varies depending on the season, time of day, environmental conditions, and tree health.
All Images from the State of Hawaii Department of Agriculture New Pest Advisory Bulletin. See advisory
Introduction: