Pest description and crop damage Leafminer adults are small flies, the most common is Liriomyza trifolii, which is about 0.125 inches long and black and yellow. The larvae are legless maggots. Mines from larval feeding in the leaves can make plants unmarketable.
Biology and life history The adult leafminer inserts its eggs into the leaf material. The egg hatches and the small white maggot mines within the leaves. The maggots then drop to the floor or substrate to pupate. Leafminers can complete a generation in about two weeks at 95°F. There can be many life cycles per season.
Scouting and thresholds Leafminers can be monitored with yellow sticky cards and looking for direct sting or oviposition damage on the leaves.
Natural enemies include:
- entomopathogenic nematodes (Steinernema feltiae)-Foliar applications in greenhouses
- parasitic wasps (Dacnusa sibirica)-Commercially available. Used for management of Liriomyza spp.
- parasitic wasps (Diglyphus spp.)-Commercially available. Used for management of Liriomyza spp.
- abamectin (Avid 0.15 EC) at 0.009 lb ai/100 gal (8 fl oz). REI 12 hr. Apply at 7 day intervals.
- acephate (Precise, Orthene TR) at 0.024 lb ai/1,000 sq ft broadcast (0.6 oz). REI 24 hr.
- acetamiprid (Tristar 30SG) at 0.5 lb ai/100 gal (2.7 oz). REI 12 hr.
- azadiractin (Azahar, Azatin XL)-Insect growth regulator. Some formulations are OMRI-listed for organic use.
- bifenthrin (Talstar) at 0.335 to 0.67 lb ai/1,000 sq ft. REI 12 hr. Restricted use pesticide.
- chlorpyrifos (Quali_Pro Chlorpyrifos) at 0.25 to 0.5 lb ai/100 gal. REI 24 hr. Restricted use pesticide.
- cyclaniliprole/flonicamid (Pradia) at 10 to 17.5 fl oz/100 gal.
- cyfluthrin/imidacloprid (Discus N/G) at 0.063 lb ai/100 gal foliar; 0.009 to 0.014 lb ai/1,000 ft soil. REI 12 hr.
- cyromazine (Citation) at 2 oz ai/100 gal. Apply to larval stage. REI 12 hr.
- deltamethrin (D-Fense Dust) at 8 oz product per 1,000 sq ft or as a thin layer.
- diflubenzuron (Adept) at 0.5 oz ai /100 gal soil. Apply to larval stage. REI 12 hr.
- dinotefuran (Safari 20SG) at 0.1 to 0.2 lb ai/1,000 ft sq; 0.05 to 0.1 lb ai/100 gal. REI 12 hr.
- fenpropathrin (Tame 2.4EC) at 0.1 to 0.2 lb ai/a (5.3 to 10.7 fl oz). REI 24 hr.
- garlic oil/powder (Allityn)-Insect repellent. Some formulations are OMRI-listed for organic use.
- imidacloprid (Marathon II) at 0.027 oz ai /100 gal foliar. Drench and irrigation permitted. REI 12 hr.
- Isaria fumosoroseus (PFR 97) at 0.175 to 3.5 lb ai/100 gal foliar. REI 4 hr.
- kaolin (Surround)-May leave residue. Some formulations are OMRI-listed for organic use.
- lambda-cyhalothrin (Scimitar GC) at 0.013 to 0.043 lb ai /100 gal. REI 24 hr. Adult leafminers only.
- mineral oil/petroleum distillate (Biocover LS)-Some formulations are OMRI-listed for organic use.
- novaluron (Pedestal) at 0.039 to 0.052 oz ai/100 gal. Apply to larval stage. REI 12 hr.
- oil of rosemary/peppermint (Ecotec for WA only)-Some formulations are OMRI-listed for organic use.
- pyriproxifen (Distance) at 0.054 to 0.081 lb ai/100 gal (8 to 12 fl oz) foliar. Apply to larval stage. REI 12 hr.
- s-kinoprene (Enstar AQ) at 0.012 to 0.024 lb ai/10,000 sq ft. REI 4 hr.
- spinosad (Entrust) at 0.156 lb ai/100 gal. OMRI-listed for organic use.