Cameraria spp.

Oak leafminer damage. Photo: Eric R. Day, Virginia Polytechnic Institute and State University, Bugwood.
Scientific Name: 
Cameraria spp.
Common Name: 
Oak Blotch Leafminer
Growing Degree Days (GDD's): 
533–912 GDD's (June), Base 50F, March 1st Start Date (Source: Cornell Cooperative Extension; Robert Childs, UMass Extension.)
Host Plant(s) Common Name (Scientific Name): 
Black oak (Quercus velutina) *Cameraria hamadryadella
Post oak (Quercus stellata) *Cameraria hamadryadella
Red oak (Quercus rubra) *Cameraria hamadryadella
Scrub oak (Quercus ilicifolia) *Cameraria hamadryadella
White oak (Quercus alba) *Cameraria hamadryadella, C. cincinnatiella
Insect Description: 

The larvae of a few species of moths in the genus Cameraria are common leaf mining insect pests of oak. C. hamadryadella is referred to as the solitary oak leafminer because a single larva maintains each single mine. C. cincinnatiella on the other hand is a gregarious species, so as many as 12 larvae may be found in a single leaf mine. Depending upon the species of leafminer, different species of oak may be impacted. (Details are included in the Host Plant section.) The exact life cycle details of each species will differ. Some generalizations can be made, however if in a given season a particular species is problematic, details about the timing of the life cycle will need to be understood prior to attempting to manage the insect. In general, Cameraria species may have 2-5 generations per year depending upon geographic location and climate. Both of the aforementioned species overwinter as pupae in dried, fallen leaves. Adult moths emerge in the spring and lay eggs on newly opened host plant leaves. By the end of the summer, feeding damage by these insects may be very apparent. 

Damage to Host: 

The feeding damage created by the larvae of these species is in the form of a blotch mine found on host plant leaves. Light to moderate infestations may be tolerated, but heavy populations of these insects may kill the leaves of their host plants. Some reports indicate that in particularly heavy population years, 80-100% of the foliage can be killed. However, it is more typical of these leafminers to cause little to no damage to their host plants - and chemical management options are often unnecessary. 

Monitoring: 

Look for first generation leaf mines following the expansion of host plant leaves. Blotch-like mines turn brown.

Cultural Management: 

Rake up and remove or destroy fallen leaves around susceptible host plants in the fall. In a landscape where oak are secluded from forested oak, this can be a very effective way of reducing the population locally. (Pupae overwinter in the fallen leaves.)

Natural Enemies & Biological Control: 

At least 14 species of parasitoid wasps are reported to reduce oak leafminer populations, and typically keep them below damaging levels naturally.

Chemical Management: 

Abamectin (NL)

Acephate (NL)

Acetamiprid (L)

Azadirachtin (NL)

Bifenthrin (NL)

Carbaryl (L)

Clothianidin (NL)

Cyantraniliprole (NL)

Diflubenzuron (N)

Dinotefuran (NL)

Emamectin benzoate (L)

Fenpropathrin (NL)

Flonicamid+cyclaniliprole (N)

Gamma-cyhalothrin (adults) (L)

Horticultural oil (L)

Imidacloprid (L)

Insecticidal soap (NL)

Lambda-cyhalothrin (adults) (L)

Malathion(L)

Neem oil (NL)

Permethrin (L)

Pyrethrin+sulfur (NL)

Spinosad (NL)

Notes: 

Management may be most helpful prior to mines reaching 1/4 inch in diameter.

Active ingredients that may be applied systemically include: Abamectin (injection), acephate (injection), acetamiprid (injection), azadirachtin (injection, soil drench), clothianidin (soil drench), cyantraniliprole (soil drench, soil injection), diflubenzuron (soil drench), dinotefuran (soil drench), emamectin benzoate (injection), imidacloprid (soil drench), and neem oil (soil drench).

Make insecticide applications after bloom to protect pollinators. Applications at times of the day and temperatures when pollinators are less likely to be active can also reduce the risk of impacting their populations.

Note: Beginning July 1, 2022, neonicotinoid insecticides are classified as state restricted use for use on tree and shrub insect pests in Massachusetts. For more information, visit the MA Department of Agricultural Resources Pesticide Program.

Read and follow all label instructions for safety and proper use. If this guide contradicts language on the label, follow the most up-to-date instructions on the product label. Always confirm that the site you wish to treat and the pest you wish to manage are on the label before using any pesticide. Read the full disclaimer. Active ingredients labeled "L" indicate some products containing the active ingredient are labeled for landscape uses on trees or shrubs. Active ingredients labeled "N" indicate some products containing the active ingredient are labeled for use in nurseries. Always confirm allowable uses on product labels. This active ingredient list is based on what was registered for use in Massachusetts at the time of publication. This information changes rapidly and may not be up to date. If you are viewing this information from another state, check with your local Extension Service and State Pesticide Program for local uses and regulations. Active ingredient lists were last updated: January 2024. To check current product registrations in Massachusetts, please visit: https://www.mass.gov/pesticide-product-registration .