Leafminers - (many species)

TYPE:
DESCRIPTION:
Aspen LeafminersLeafminer damage
Helen Atthowe - Missoula County Extension
 Phyllocnistis populiella Adults are moths (1-1/4 inch long); larvae are tiny, pale caterpillars. Hosts are aspen, cottonwood, and willow with one generation per year.
Birch Leafminersbirch leafminer damage and larvae and frass
E. Bradford Walker, Vermont Dept. of Forests, Parks & Rec, www.ipmimages.org
 Fenusa pusilla A tiny wasp; larvae are whitish, translucent, 1/8 to 1/4 inch long with several generations per year.
Lilac Leafminerslilac leafminer
Helen Atthowe Missoula County Extension
 Caloptilia syringella Larvae are green and found in mines or folded leaves, uses lilac as its host species and has one generation per year.
Adults are small moths that fold their wings tubelike over the body and are gray with reddish brown patches.

Spinach/Chard LeafminersSwiss chard
Helen Atthowe Missoula County Extension


 Vegetable Leafminer adult  Adult
UC - Davis, Pests of the Garden and Small Farm - Puplication #3332

 Liriomyza spp. Adults are tiny flies; larvae are white and maggot-like. They feed on spinach, chard, beets and lambsquarters.


Damage: Larval leafminers burrow underneath leaf surfaces leaving a visible trail as they eat their way through the leaf. Leafminers can be flies, wasps, moths, or sawflies. Leaves damaged by leafminers have a distinct top and bottom leaf surface that can be pulled apart at the tan-colored blotch or serpentine trail. Inside trails or blotches, you will find a larva or the black, sawdusty leafminer droppings.

LIFE CYCLE: Varies depending on species.

CONTROLS:

Biological: There are native parasitoids of leafminers. Avoid general insecticides that kill these parasitoids. In New England, releases of European ichneumonid wasps in the 1970's are now resulting in significant reduction of birch leafminer close to the original release sites .

Mechanical: Applying row covers as soon as plants emerge may aid in controlling those leafminers which attack vegetable crops; yellow sticky traps are also somewhat effective at trapping adults if pest populations are low.

Chemical: Spinosad: apply at 1st larval hatch, when larvae are 1/8" or shorter. Both Spinosad and Neem inhibited feeding and egglaying of leafminers on Chrysanthemum up to 24 hours after application . When 1% neem seed extract was sprayed to runoff on birch tree foliage containing eggs or early instars of birch leafminer, larval mortality was greater than 99% . According to USDA studies in Maryland, neem has some systemic activity against leafminers when applied as a soil drench; neem soil drenches are an option for vegetable leafminers if applied early. Also, Abamectin (Avid).
Missoula County Extension Office; Missoula, Montana 59808 - Updated for 2006