The best DIY kit for emerald ash borer is one labeled for the beetle that places a systemic insecticide at the root flare early in the growing season, with the dose matched to trunk size. Emerald ash borer, a wood boring beetle, attacks even healthy ash trees, so protection depends on a systemic treatment rather than fertilizer or general care.

Why does emerald ash borer call for a systemic treatment?

Because it bores into the wood, emerald ash borer feeds where a spray on the bark or leaves does not reach, and TreeHelp's guidance is that protection requires a systemic insecticide. A systemic is taken up and carried through the tree's vascular system, so it reaches the insects feeding within.

How does a DIY trunk injection work?

Early in the growing season, when treatments are most successful, the Multi Insect Killer Tree Injection Kit is injected through shallow holes drilled at the root flare, the point where the trunk widens at ground level, using the syringe and tip included in the kit. The kit lists emerald ash borer among the insects it controls, with visible results within two weeks and control for the rest of the season.

How many trees can one kit treat?

One kit holds enough insecticide for 15 application sites, enough for fifteen trees 4 inches around or a single tree 60 inches around. Trunk circumference decides how many of those sites one tree uses.

Frequently Asked Questions

Can the same ash be injected every year?

Not indefinitely. Holes should be drilled no more than once a year, and in no more than two consecutive years, because every hole is a wound.

Is there a DIY option that avoids drilling?

Yes. Where an injection means drilling into the trunk, Once A Year Insecticidal Drench w/Merit is mixed and poured at the base instead, at 1 oz of concentrate per inch of trunk circumference, for 12 months of protection.

Should a heavily infested ash still be treated?

Not always. The borer has to be addressed first, and an arborist can judge whether a badly damaged tree is still a good candidate for treatment.

Does the injection kit work on conifers?

Not reliably. Injections into conifers may be slow to take up or not taken up at all.