Why June mushrooms are hardly ever wormy

If you've picked mushrooms in August, you know the disappointing feeling: you cut a beautiful porcini, and it's riddled with worms. In June this happens much less often. Early mushrooms are often surprisingly clean, and that's one of the reasons experienced foragers value early summer so much.

Let's look at why June mushrooms are almost never wormy, which ones resist larvae best, and how to bring a clean basket home from the forest.

Why there are fewer worms in early summer

The “worms” in mushrooms are actually insect larvae, mainly of fungus flies and fungus gnats. The adult insect lays eggs in the mushroom, and they hatch into larvae that bore through the flesh.

In June there are still relatively few of these insects. After winter their numbers are only starting to grow, so the pressure on mushrooms is low. On top of that, nights are cooler in early summer, and in the cool, larvae develop more slowly.

But by August the insects have multiplied, the heat speeds up larval development, and the same mycelium now yields mostly worm-eaten mushrooms. That's why June, with its cool nights and few insects, gives the cleanest harvest.

Which mushrooms resist worms best

Not all mushrooms are equally tempting to larvae. Some hardly ever get wormy, whatever the month.

• **Chanterelle.** The champion of cleanliness. Its flesh contains natural substances that repel larvae, so the chanterelle is almost never wormy, even in the heat.
• **Porcini.** Larvae move into a young porcini with firm flesh more slowly, especially in June.
• **Slippery jack.** The slippery jack, on the contrary, gets wormy quickly because of its tender flesh, so it's best picked very young.

The general rule: the firmer and drier a mushroom's flesh, the more slowly worms bore through it. That's why firm young specimens are always cleaner than old, soggy ones.

How to gather a clean basket

A few simple habits will help you bring fewer wormy mushrooms home from the forest.

• Pick young mushrooms. Larvae work their way from the bottom up, so old mushrooms are almost always worm-eaten, while young ones are often still clean.
• Check on the spot. Break the stem near the base: if you see dark tunnels and little holes, the mushroom is wormy and better left behind.
• Don't put doubtful mushrooms in with the rest. Larvae crawl from mushroom to mushroom in the basket, so one bad apple spoils the whole barrel.
• Go out in the morning. It's cool overnight, the mushrooms are fresh, and the larvae are less active.

Why a few tunnels are nothing to fear

If a nice mushroom turns out to have a few worm holes, don't rush to throw the whole thing away. Often it's enough to trim off the affected part and use the rest.

This is common practice: a porcini with a little worm damage near the base is perfectly usable if you cut out the stem and keep the clean cap. Only throw away badly affected mushrooms, where there are more tunnels than flesh.

Overall, the best way to avoid wormy mushrooms is to go out at the right time. The first flush after a warm rain gives the cleanest specimens, so keep an eye on the weather with the mushroom radar and don't put off your outing.

Sources

• “Key to the Fungi of Ukraine” (Kyiv, Naukova Dumka publishing house).
• Cantharellus cibarius in GBIF, the global biodiversity database.
• Fungi in MycoBank, the international fungal nomenclature database.
• Mushroom hunting on Wikipedia.