Question
Hey Mack, We've got some kind of bug making lace out of our eggplants. We planted several established plants several weeks ago and now they are being attacked. Any ideas?

Answer
Dear Brad:

I think you have an invasion of Vegetable Leafminer Flies.  
The adult is a small fly, approximately 1/8 inch long, with a black head, yellow between the eyes, a black thorax and a tube-like "ovipositor" at the end of the abdomen used to puncture the upper leaf surface for egg laying. The white, oval egg is inserted in the leaf tissue, but many punctures (called stipples) are used by the adult for feeding and do not contain eggs. The larva, a yellow maggot with black, sickle-shaped mouth hooks, feeds between the upper and lower leaf surface for approximately seven days, leaving a serpentine mine containing a string of black frass (fecal matter). The mature larva exits from the mine and falls to the ground (or plastic mulch) where it molts to a pupa within a golden brown, barrel-shaped and ribbed, puparium from which the adult emerges in seven to 14 days. Generation time is 15 to 28 days depending upon temperature.  Leafmines reduce photosynthetic area and may provide entry points for foliar pathogens. Heavily damaged leaves become necrotic, predisposing fruit to sunscald.

Control: Safer Yard and Garden Insect Killer.  An environmentally friendly solution. Kills insects on contact, gentle on plants. Use on flowers, vegetables, shrubs, and ornamentals. Use Up To Day of Harvest. Potassium salts (insecticidal soap) weaken the insects protective outer shell. Pyrethrins in the product attack the insects nervous system.  Follow manufacturer's label instructions explicitly in order to get the best results.

Good luck and best wishes for a good crop.

Sincerely,

Mack Jean
AllExperts
Master Gardener
Tennessee