Diglyphus isaea
10% off your first 4 orders, then 15% off every order after.
Heads up—this is just an estimate. We only ship when the bugs are happy and ready to travel (Mon–Thurs). If a colony needs a beat to peak, or we're propagating a fresh batch, your order might hold up to a week. Treatment bottles jump the line when you've got an active infestation.
Sizing guide
How our sizes work
Sizes are set by how many plants you are treating — not by how much material is in the container.
Every size on every product page names its own coverage right there in the dropdown, so you never have to come here to find a number. Medium — Up to 25 Plants (2,500 Mites) tells you the tier and the count in one line. This page is for the part the dropdown cannot tell you: how to pick between two of them.
These are rough middles. The ladder runs smallest to largest within each product, so a Medium of one species covers more ground than a Medium of another — a nematode drench and a beetle release are not the same job. The count on the size you are looking at is always the real answer.
Pest pressure moves you up the ladder
Plant count is only half the sum. The other half is how much pest is already there. A closed tent holding fifteen plants with thrips on every growing tip needs a larger release than a bright room holding forty plants with a few gnats — the population you are outnumbering is bigger, and the enclosed space lets it rebound faster.
Coverage figures assume a typical active infestation. Adjust from there:
Under heavy pressure, two releases beat one large one. Take the larger size and plan a second release 7–14 days later, which catches the eggs that had not yet hatched the first time.
A few things work differently
A few products read in square feet rather than plants, because that is how they are applied — the outdoor and area-scale releases. Those are Sc and Hb nematodes, Coleomegilla, and the aphid specialists Ervi, Matricariae, and Aphidoletes. Same ladder, different unit.
Sf nematodes and Triple Blend size by plants and pots, like everything else. They are soil drenches for potted plants, so count your pots rather than your floor.
Slow-release sachets have no size. They are sold by the sachet, and you place one per plant or one per few plants depending on pressure. Sachets are a prevention tool — they hold a population in place before a problem starts. If something is already established, a bottle is the correct answer.
Sizing up is cheaper than sizing twice. Predators need enough prey to establish and enough of themselves to find it. Underdosing is the most common reason a release underperforms, and it usually costs more in the end than the larger size would have. When you are between two sizes, take the larger one.
Still not sure? Tell us what you are growing and what you are seeing, and we will size it for you.
Diglyphus isaea
At A Glance
Diglyphus isaea is a highly effective parasitic wasp and the premier biological solution for controlling Leafminers (Liriomyza spp.). Unlike other predators that hunt on the leaf surface, Diglyphus is a specialized ectoparasitoid that locates leafminer larvae hidden inside the leaf tissue. The adult female stings and paralyzes the leafminer before laying an egg next to it, providing an immediate stop to leaf damage. This is a crucial tool for aroid collectors and commercial growers looking to preserve the aesthetic integrity of high-value foliage.
Field Notes — Diglyphus isaea
| Species | Diglyphus isaea |
| Common name | Leafminer parasitoid |
| Type | Parasitic wasp — ectoparasitoid |
| Ships as | Adults |
| Sold by | Count |
| Size | 2–3mm. Small black wasp. Does not sting people |
| Hunts | Leafminer larvae inside the mine — Liriomyza species primarily (L. trifolii, L. huidobrensis, L. bryoniae), also Chromatomyia |
| How it works | Female stings and paralyzes the larva inside the mine, then lays an egg beside it. Her offspring feeds externally on the paralyzed larva and pupates in the mine |
| Also kills by | Host feeding. Females puncture and feed on larvae they don't parasitize — this accounts for a meaningful share of the total kill |
| Eats opportunistically | Nothing else. No alternate prey, no pollen diet |
| Won't touch | Thrips, aphids, mites, whitefly, fungus gnats, adult leafminer flies, eggs, or mines the larva has already left |
| Target stage | Second and third instar leafminer larvae. Early mines are too small; vacated mines are too late |
| Optimal temp | 68–86°F (20–30°C). Slows markedly below 60°F |
| Humidity | 50–70% RH. No high-humidity requirement |
| Light | Needs daylight to search and fly. Won't work in a dark room |
| Egg to adult | Roughly 2 weeks at 77°F |
| Adult lifespan | 2–3 weeks with a nectar or honey source; considerably less without |
| Establishes | Yes, while leafminer hosts are present. The population collapses when they run out |
| Deploy | Immediately on arrival. Open the container in the canopy and let them walk or fly out |
| Release timing | Morning, in daylight. Repeat weekly while mines are active |
| Refrigerate | No |
| Compatible with | Predatory mites, Stratiolaelaps scimitus, beneficial nematodes, lacewings, ladybugs, springtails |
| Keep separate from | Broad-spectrum and systemic insecticides — systemics move into the mine and kill the developing parasitoid. Yellow sticky cards will catch adults; pull them at release |
| Chemical interval | One day after neem oil or insecticidal soap. Never with sulfur, at any dilution |
| Safe around | Pets, children, plants |
Target Pests
Environmental Needs
Selection Guide
How to Use
How They're Shipped
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FAQ
What is your Live Delivery Guarantee?
We guarantee that your beneficial insects will arrive healthy and ready to work. Because we are shipping live organisms, we use packaging and expedited shipping to ensure their safety. In the rare event that your order is compromised during transit, please take a photo of the package and contact us within 24 hours of delivery so we can make it right.
Do these wasps sting humans or pets?
How do I know if they are working?
Can I use these with yellow sticky traps?
How long does a release last?
Why are these more expensive than generalist predators?
Can I use these alongside Lacewings or Mites?
Help! I'm overwhelmed
Yeah, it's a lot the first time you're using predatory mites. Please email us at info@fgmnnursery.com and we'll be happy to help!
I don’t see anything moving in my bottle or sachet. Does that mean they’re dead?
Not at all! In fact, go ahead and deploy them.
Predatory mites are microscopic (often less than 0.5mm) and naturally blend into their carrier medium (bran or vermiculite).
- For Bottles: The mites often huddle in the center of the bottle for insulation during transit.
- For Sachets: These are "slow-release" nurseries. The mites stay tucked deep inside the breeding media and emerge one by one over 2–4 weeks. Seeing an "empty-looking" sachet or bottle is not proof of a loss; it is simply how they are packaged for maximum survival.
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