Elm Leaf Beetle Treatment Southern Highlands
Do you live in the southern highlands? You may not have heard about the Elm Leaf Beetle. Yet. It’s here.
In July 2017, starting in Mittagong, I found it had spread to Bowral, High Range, Burradoo, Moss Vale, Sutton Forest, Exeter, Bundanoon and Berrima and had attacked every Elm I stopped to look at. Fitzroy Falls, Kangaloon and Robertson were the same. Judging by the level of foliage damage, it is in its second or third season in the Highlands. This means there is a significant build up of the beetle population sufficient enough to defoliate a 50 year old Golden Elm, by February, having started in October in one growth season. The only reason the Grand English Elms we love and Golden Elms weren’t seriously attacked by Christmas was the late zero degree frost in October.
But hoping there’s a frost is hardly a reason not to protect your elm against the inevitable. We can provide an effective level of protection of your tree for up to 3 growth seasons or part thereof. Last spring(2017), the Highland Elms, were lucky, but the beetle numbers have been increasing since then, as they do, because ELB cannot be eradicated, and you will see shot holes in the leaves then the larvae causing leaf skeletonising till late March -April. In fact, the beetles will hibernate and emerge in October typically; and the cycle continues.
Repeated defoliation results in terminal bud dieback and loss of the Canopy curvature with resultant tertiary (branchlet) dieback. If prolonged, sporadic dieback of primary and secondary laterals will occur, because photosynthesis will be repeatedly interrupted and photosynthate-storage will be reduced ; ultimately major laterals i.e. the scaffold branches of the tree will go into decline and die.
Sooner or later, most of the Elms in the Highlands will be decimated. Every leaf turns brown, curls and drops.
Proof of Treatment
St Peters Boys school Adelaide
Classic weeping elm
PROOF OF TREATMENT Summer 2015 on 3 Golden Elm Cultivars
1ST Cultivar 20 years old
2nd Cultivar Front view Summer 2015
Reverse view Summer 2017
2nd Cultivar 35 years old. Summer 2015
3rd Cultivar 50 years old. Late Summer 2016
When are the Beetles most active and what damage do they make??
Stem injection ONLY
What we do
Why we wont spray
Ladybirds and Assassin bugs help the natural predators colonise your garden.
WHAT YOU CAN DO
(A) Interrupt the life cycle
1. 3 DAY DUCT tape
DUCT tape is the safest method. CHANGE IT EVERY 3 DAYS.
Sticky pads can melt , running down trunk and blocking the lenticels of
the bark preventing the bark from breathing
2.Clear all litter from around each tree for 500mm and keep as bare
3.So when pupae settle there you sweep them up and drop them into
a bucket of water
(B) Irrigation particularly in hot dry climates like Adelaide
1. Water heavily before and after for a couple of weeks each time
your tree is injected then once per week through summer in hot
Damage from injectors methods to avoid
I don’t leave plastic plugs in your trees. I only drill a 3.5 mm hole using a sterile drill bit, a sterile injector, and a sterile filler nozzle. The images below show what should NOT be done.