Elm Leafminer

Kaliofenusa ulmi

Elm leaf miner, Fenusa ulmi,  is a native pest that feeds on the tissues in between the outer layers of elm leaves, causing browning and leaf drop. Although primarily an aesthetic pest, leaf miner damage can stunt or weaken your tree when the population in your tree is large.

Download Elm Leafminer Fact Sheet

Treatment Strategy

Which product to use is determined by the time of year treatment will be applied.

Minor infestation of Elm leaf minor does not affect the health of the tree or its appearance. Major infestations will cause the entire tree to look brown and compromise its ability to make sugar, which can compromise its health. Treatments for Elm leaf miner are effective, and can also protect the tree from aphids and other sucking insects that are common on elms.

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Elm Leafminer Treatment Option 1

Early spring or late fall treatment with Optrol™ is extremely effective against leaf miners. Most arborists use Xytect™ as a fall application to control leaf miner in the early spring because it needs a minimum of 30 days to reach the leaves. Xytect™ is easily drenched at the base of the tree, providing one year of protection.

Application Type – Soil drench

DIY Product/Equipment Needed:

Optrol™

• Soil drench kit

• Measuring or diameter tape

• Bucket or watering can

• Measuring cup

• Gloves

Elm Leafminer Treatment Option 2

Spring applications need a faster insecticide such as Transtect™. Transtect™ moves into your tree within 2 weeks and provides control for 2-3 months. Transtect ™ applications should be done in mid-to-late April to control feeding crawlers before they drop to the soil to pupate.

Application Type – Soil injection

DIY Product/Equipment Needed:

Transtect™

• Measuring or diameter tape

• Soil injection kit

Elm Leafminer Treatment Option 3

Cultural practices such as watering, mulching and low nitrogen fertilization can help affected trees regain vigor after significant leaf loss.

Elm Leafminer DIY Kit

Option 1

Application TypeSoil drench

DIY Product/Equipment Needed:

Optrol™

• Soil drench kit

• Measuring or diameter tape

• Bucket or watering can

• Measuring cup

• Gloves

Option 2

Application TypeSoil drench

DIY Product/Equipment Needed:

Transtect™

• Soil drench kit

• Measuring or diameter tape

• Bucket or watering can

• Measuring cup

• Gloves

How Is It Spread?

• Adults lay eggs in leaf tissue in April and May

• Eggs hatch and larvae begin feeding between leaf layers

Larvae finish feeding in late May to early June and fall to ground

Larvae burrow into the soil and build a cocoon to pupate

• Pupae remain underground for the summer, fall and winter

Susceptible Trees

Siberian, Russian, slippery, American elm, and English elms are all commonly infested with elm leaf miner.

Symptoms

• Small whitish spots (halos) on leaves in May

• Blotch-like mines appear in mid-May

• Mines join together into tan papery patches

• Mined areas of leaves may fall out and leave holes in the leaf

• Brownish foliage that looks sickly

Lookalikes

Dutch elm disease

Related/Similar Problems

Dutch elm disease

Timing

Spring or Fall

Urgency

Low

Risk of Spreading

Low

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