Winter Moth, an introduced pest causes severe defoliation in hardwood trees. Winter Moth is appropriately named since adult moths can be active from November through January. Larvae feed early on developing leaves and severe infestations will defoliate trees. In June they drop to the ground to pupate in the soil until fall. Canadian research has shown 4 consecutive years of defoliation can lead to tree mortality.
A: Larval stage Winter Moth (caterpillar)
B:
Adult stage Winter Moth (moth)
C: Leaf
defoliation caused by Winter Moth larvae
Photos from Foresty Images forestryimages.org
Photo A taken by Louis-Michel Nageleisen, Département de la Santé des Forêts – France. Photos B and C taken by Hannes Lemme.
Arborjet recommends a well timed trunk Micro-infusion™ using ACE-jet with the Tree I.V. system using the Arborplug Technology when caterpillars are present. ACE-jet is compatible with the micro-elementts MIN-jet IRON, MIN-jet Calcium and PALM-jet for a 2 in 1 application, The botanical Ornazin 3% EC may also be used. Ornazin 3% EC is manufactured by SePRO. The active ingredient in Ornazin 3% EC is azadirachtin, derived from the neem tree. Azadirachtin is an insect growth regulator (IGR) that prevents the development to the adult (moth) insect. Azadirachtin also acts to deter feeding. Select the Tree I.V. system using Arborplug Technology. Other injection devices to select for this application include the Hydraulic, and the ProCap. These systems enable the arborist or tree custodian to rapidly inject a precise dose of medicament directly into the xylem tissue, assuring a quick plant response.
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.
Use ACE-jet in the spring, when caterpillars or damage first appears. Timing is critical as ACE-jet will only remain active in the tree for approximately 2-4 weeks. Alternatively use Ornazin 3% EC when damage first appears.
ACE-jet micro-infusion in the spring will uptake very quickly and caterpillars will die rapidly. Monitor trees annually to determine the need for a repeat treatment.
Arborjet is currently working
to register a new insecticide for leaf chewing insects. This new insecticide will have a
residual in the tree for several years.
Call Arborjet for more details at
1-866-ARBORJT.
Above: Linden on left (A) was untreated, and Linden on the right (B) was treated with ACE-jet using the Tree I.V.
Top Right: Infested Linden treated with ACE-jet with the Tree I.V. shows new foliage growth after treatment.
Bottom Right: Healthy maple with no Winter Moth damage
Images from: Arborjet Inc. research, forestyimages.org, and Anette Linnea Rasmussen – fotolia.com
