The Fleming Arboretum has two large Wiliwili - one planted in 1952, the oher in 1976. The following are notes on an every-5-month-treatment of these Wiliwili using the Merti Systemic Insecticide.
Jan 1, 2006: First sighting of Gal Wasp stings.
Jan 12, 2006: Merit injections made into large trunks bases every 6 inches.
Feb 2006: Older, larger WiliWili shows less response.
May 25, 2006: Merit injections - 6 inch intervals on all branches up to 5 feet.
June, 2006: Trees show galling but doing okay.
Nov 28, 2006: Trees dormant - Merit injection.
Dec, 2006 - Mar, 2007: Trees still dormanat - question of dormancy or Gall Wasp effects.
Apr, 2007: New growth
May 15, 07: Merit injections
End of May, 07: Trees go into dormancy
End of August, 07: New healthy leaves
September, 07: Merit inject early… concerned that chemical would not have thoroughly traveled throughout tree during dormancy.
October, 07: All new leaves attached by galls. This may be evidence that the Merit injection in May at beginning of dormancy did not travel thru tree so new leaves in October were vulnerable.
October 24, 07: Chemical has taken effect in 6 ˝ weeks.
New leaves are not attached.
November thru January 08: Trees look good
February 28, 08: Merit inject
March to April, 08: Dormant
May 15, 08: Out of dormancy. New growth no damage
September 11, 08: Merit injection done late-6weeks and 11 days. We previously were averaging injections every 5 weeks tho recommended every 6 weeks on label.
October 23, 08: Gall damage
November 1, 08: Galls dead, which means it took 7 weeks for chemical injections to take effect.
Field Test Notes:
- Chemical into the cambium during dormancy does not travel throughout the tree.
- Wiliwil dormancy is approximately 3 months.
- It takes 6 weeks for merit to travel throughout the Fleming Arboretum’s 20-25 foot tall Wiliwili trees.
- 5 month preventative Merit injection most successful, not 6 months as instructed on label.
