Betabaculovirus cypomonellae (Cydia pomonella granulovirus)
A virus that infects codling moth larvae, sold as Cyd-X and Madex HP (Madex HP is also labelled for oriental fruit moth). The larva has to eat it, so it must be on the fruit and leaves in the short window between an egg hatching and the young caterpillar boring into the fruit. Infected larvae stop feeding and die in 3–7 days. UC IPM found weekly sprays through egg hatch as effective as carbaryl in backyard trees, with no preharvest interval and no harm to other insects. The catch is timing and persistence: sunlight breaks it down within about a week, so it has to be resprayed through each egg-hatch period.
At a glance
- Mode
- Must be eaten by a young larva
- Label rate
- Cyd-X 1 tsp / 5 gal; Madex HP ½ tsp / 5 gal
- Speed
- Death in 3–7 days
- On the tree
- Respray after 7–8 sunny days (Cyd-X) or 6–8 (Madex HP)
- Harvest
- Up to and including the day of harvest
- REI
- 4 h on agricultural labels
How it works
The active ingredient is a baculovirus, now named Betabaculovirus cypomonellae, packed in protein capsules called occlusion bodies. A codling moth larva that eats them on a leaf or on the fruit skin dissolves the capsules in its gut, the virus multiplies in the gut lining and then the rest of the body, and the larva stops feeding and dies in 3–7 days, faster in warm weather. The dead larva breaks down and releases more virus. The Cyd-X label says baculoviruses have been found only in invertebrates and that the virus does not reproduce in mammalian cells.
Because the larva has to eat it, the virus only works on a newly hatched caterpillar before it bores into the fruit. That makes timing everything. The first spray goes on at the start of egg hatch: the Cyd-X label says about 250 degree days (°F) after biofix, UC IPM says 200–250 degree days after you begin regularly catching moths in a pheromone trap, or as soon as the first stings appear. The labels ask for at least two sprays per generation; UC IPM's home-garden advice is weekly, 3 or 4 times per generation. Sunlight inactivates it, so it has to be renewed after about a week of sun. UC IPM adds that 1% horticultural oil in the tank improves it. Codling moth in Europe became resistant to the original virus isolate after years of intensive use, and in 2022 researchers confirmed the first US case, in moths from an organic Washington apple orchard; some newer isolates still infect resistant larvae.
Applying it
Cyd-X and Madex HP are liquid concentrates measured by the teaspoon into a hand-pump sprayer. The rates below are from the homeowner sublabels of the EPA-stamped Cyd-X and Madex HP labels; the agricultural sublabels give 1–6 fl oz (Cyd-X) and 0.5–3 fl oz (Madex HP) per acre.
Keep it cold
Heat kills the virus. Store Cyd-X below 86 °F, ideally in the fridge or freezer; Madex HP says below 41 °F.
Neutral water
Mix with water near pH 7. Cyd-X asks for non-chlorinated water. Spray enough to wet all leaves and fruit without run-off.
At egg hatch
First spray as first-generation eggs hatch, in late spring or early summer. The labels say at least two sprays per generation; UC IPM advises weekly, 3–4 per generation.
After a week of sun
Reapply after 7–8 sunny days (Cyd-X) or 6–8 (Madex HP) while moths are still laying. The Madex HP label says up to 6 sprays may be needed in a long hatch.
Pesticide sensitivity
Codling moth in Europe became resistant to the original granulovirus isolate after years of intensive use. A 2022 study confirmed the first US case: moths collected from an organic apple orchard in eastern Washington, where the virus was sprayed often, were partly resistant to every granulovirus product then sold in the US, though some newer experimental isolates still infected them. The reported cases come from commercial orchards; we found no report from backyard trees. Check a product →
When to choose something else
The granulovirus does one job: it kills young codling moth larvae before they get into the fruit. Choose something else when:
- The larvae are already inside the fruit — nothing sprayed on the skin reaches them; pick and destroy infested fruit
- You would rather not spray at all — bagging the fruit at ½–1 inch is the one non-chemical method UC IPM says works on its own
- The caterpillars are eating leaves — use Bt kurstaki, which the virus does not replace
- The damage is gum at the base of a peach tree — that is peachtree borer, and nematodes are the biological option
- You cannot keep it cold — product stored warm loses activity
Where to buy
These are the EPA-registered codling moth granulovirus products whose labels we checked, in alphabetical order. They are not ranked. helpfulbugs takes no commission and does not sell any of them.
- Cyd-X (Certis, EPA Reg. 70051-44)Liquid concentrate; farm and homeowner directionsUS · HOME & FARM
- Cyd-X Plus / Cyd-X HP (Certis, EPA Reg. 70051-112)High-potency liquid concentrate; farm and homeowner directionsUS · HOME & FARM
- Madex HP (Andermatt USA, EPA Reg. 69553-1)Liquid concentrate; farm and homeowner directionsUS · HOME & FARM
Betabaculovirus cypomonellae (Cydia pomonella granulovirus) by target
Rate and timing differ by what you are releasing it against. Each page below is the program for one pest.