Diglyphus for natural leaf miner control

Description

Diglyphus isaea is a parasitic wasp that controls leaf miner pests in field and greenhouse crops. The adult wasps are 1.5 to 2mm long and a dark metallic blue/green in color, often appearing black. The larvae are bluish green or yellow maggots 2.5mm long. These beneficial insects search for host larvae of suitable size within leaf tissue and sting them through the leaf cuticle. The sting paralyses the host larva within a short time, and the female wasp then lays one or more eggs alongside it. The hatching Diglyphus larvae feed externally on the paralyzed, but still living, host (ectoparasitism). Parasitized larvae can be recognized by the lack of movement within the mine and discoloration. They will often move away from the end of the mine, where a healthy larva would be actively feeding, and the mine stops growing. Adult Diglyphus wasps will also feed on leaf miners. A single female wasp will feed on numerous leaf miner larva during her lifetime in addition to laying several dozen eggs. Diglyphus can establish quickly after the first release.

Target Pests

Diglyphus isaea is a widespread parasitoid of leaf miner larvae and has many host species. It is of commercial interest as a control for the tomato leaf miner (Liriomyza bryoniae), the serpentine leaf miner (L. trifolii), the pea leaf miner (L. huidobrensis) and the chrysanthemum leaf miner (Phytomyza syngenesiae).

Life Cycle

Except for the adults, all life stages of Diglyphus occur hidden within leaf mines. They develop through four life stages: egg, larva, pupa and adult. Egg to adult development takes about 2 weeks in warm temperatures with several generations a year. 

Instructions for Use

• Release early in the morning or late in the afternoon.
• Hold the bottle horizontally and carefully remove the lid while standing near the crop.
• Release the biocontrol agents by gently tapping the opened bottle while walking through the target area.
• Leave the open bottle upright in the infested area for a few hours to allow any remaining parasites to escape.
• If needed, hold in darkness at 55-60°F in moderately humid environment for no more than 18 hours.

 Application Rates

0.25 to 0.5 predators per 10 sq. ft. Two releases one week apart are recommended. 

Further Resources

Leaf miner Diglyphus Parasitoids – UC IPM