Chestnut

Cut green burrs and shredded husks scattered under the tree well before the crop is ripe, and a canopy visibly thinning of burrs. A day's nut drop simply gone when you come out the next morning. Squirrels working the branches at dawn and dusk in September and October, and caching activity in nearby beds and lawn. On young trees, gnawed bark at the base, especially where mulch or long grass sits against the trunk, and vole runways showing when the snow melts.

There is no way to exclude squirrels from an open, mature nut tree, so the realistic answer is speed and volume: gather daily, plant more than one tree, and accept a share going to wildlife. Trapping is largely futile, since new squirrels move into cleared territory within weeks. Vole damage is the one you can act on - clear cover, fit guards, and check young trunks each winter; a tree girdled all the way round rarely recovers, so this is prevention rather than treatment.

Gather every single day through the drop - promptness is the entire defense, and a drop left for two days is usually a drop lost. Some growers pick nearly-ripe burrs by hand and open them under cover to beat the wildlife outright. Keep the orchard floor short and clear so caching is less attractive and so you can see what has fallen. For voles, pull mulch and grass back from the trunk, fit a wire mesh guard around the base of every young tree, and keep the guard in place through winter. A metal trunk baffle can slow squirrels on a young tree, though it stops mattering once branches from anything else reach the canopy.

Squirrels are the single biggest obstacle between a home chestnut tree and a harvest. They start on the burrs while the nuts are still green, cut whole burrs off the tree, and clear the ground drop within a day - caching far more than they eat. Chipmunks and blue jays work the same crop. Because a mature chestnut is a 40-60 foot tree, none of the usual fruit defenses apply: there is nothing to net and nothing to cage. Voles are the other half of the problem and the more serious one for a young tree: they chew bark off the trunk at ground level under mulch and winter snow, and a stem girdled right around is dead in spring.

On a resistant tree, treat blight as an annual winter inspection job, not a catastrophe.

Sunken or swollen orange-brown to cinnamon patches on the bark, often cracked, sometimes with fine orange pimples on the surface. A branch whose leaves suddenly wilt, turn brown and hang on rather than dropping - then trace down the stem to find the canker below it. Fans of buff-colored fungal tissue under bark peeled back at the canker edge. Vigorous sprouting from the trunk or base below a dying top, which is the tree responding to being girdled.

There is no spray cure. Cut infected limbs out well below the visible canker, into clean wood, and burn or bin the prunings rather than leaving them under the tree. On a resistant Chinese or hybrid tree, cankers are commonly contained by the tree itself and the job is monitoring and pruning. On a susceptible tree the top is eventually lost whatever you do; the roots usually survive and resprout. Hypovirulence treatment - deliberately introducing a virus that weakens the fungus - is used in research and by some restoration groups but is not a practical home remedy.

Plant blight-resistant stock: Chinese chestnut (C. mollissima) or American-Chinese hybrids such as the Dunstan types, especially anywhere in the former range of the American chestnut. Avoid the large European x Japanese varieties like Colossal east of the Rockies. Then minimize wounds, since the fungus needs one to get in: prune only in dry weather in late winter, keep mowers and trimmers away from the trunk, and cage against deer antler rubbing and rodent chewing. Disinfect pruning tools between trees. Keep trees unstressed - drought-stressed and poorly sited trees wall off infections less effectively.

The fungus (Cryphonectria parasitica) that destroyed the American chestnut as a forest tree, killing an estimated three to four billion trees after arriving on imported nursery stock around 1904. It enters through wounds in the bark, grows in the living tissue, and forms a canker that expands until it girdles the stem - everything above the canker then wilts and dies while the roots stay alive and send up new sprouts, which get infected in their turn. Spores travel on wind, rain, insects, birds and pruning tools. The fungus is now endemic across the entire former range of the native tree, which is why species choice matters so much: Chinese chestnut and its hybrids tolerate infection and wall it off, while American and most European varieties do not.

Wet clay kills chestnuts as reliably as blight does, and far less dramatically.

Overall yellowing, undersized leaves, thin canopy and dieback starting at the top of the tree. Dark, inky, wet-looking staining or bleeding at the root collar and lower trunk. Reddish-brown discoloration under the bark at the base when cut into. Decline concentrated in low, wet or compacted parts of the site, and worsening after a wet season.

There is no practical cure once a tree is infected - improve drainage immediately, pull soil and mulch away from the collar, and stop supplemental water. A declining tree is usually lost, and replanting a chestnut into the same wet spot repeats the result; move to a well-drained site instead. This is a disease you prevent by where you dig the hole.

Site selection is the whole defense, and it happens once. Plant on deep, well-drained, slightly acid sandy or loamy soil, preferably on a slope; never plant a chestnut in heavy clay, a low wet spot, or ground where water stands after rain. Do not overwater established trees or run irrigation against the trunk. Keep mulch pulled back from the root collar so it does not stay wet. Buy trees from a clean nursery, since the pathogen moves in infested soil and container media.

A water-mold root and collar rot (Phytophthora cinnamomi and relatives) and the second great killer of chestnuts after blight - historically it destroyed chestnut orchards across the American South and southern Europe before blight ever arrived. It attacks the roots and root collar in wet, heavy or poorly drained soil, rotting the tissue and cutting off water to the crown, so the tree yellows, thins and dies from the top down over one or more seasons. The name comes from the blue-black staining and bleeding that appears at the base of an infected trunk. Chinese chestnut carries more resistance than American or European chestnut, but no chestnut survives waterlogged ground.

Float-test, refrigerate the same day, and clear the orchard floor in fall - do those three and the problem stays small.

Neat round exit holes about the size of a pencil lead in the shells, usually appearing days after harvest rather than at gathering time. Cream-colored, legless, C-shaped grubs inside cracked nuts. Nuts that float in the water test. Fine frass in a storage container. Adults - small weevils with a very long curved snout - on the burrs in late summer.

Nothing rescues an infested nut - discard it, and do not compost it where the grub can reach soil. Because the larvae spend most of the year in the ground beneath the tree, keeping the ground clean and disturbed is the practical control; poultry ranging under the trees are genuinely effective at reducing populations. Insecticide programs exist for commercial orchards but are rarely worth it in a home planting where daily gathering and cold storage do most of the work.

Sanitation is the whole game. Gather nuts daily so grubs have no chance to exit into your soil, and clear every fallen burr and leftover nut at the end of the season rather than leaving them under the tree. Float-test every batch and discard the floaters. Then break the cycle in storage: refrigerating the crop promptly stops the grubs developing, and a brief hot-water dip (about 120°F for 20 minutes) before drying and refrigerating is the traditional home treatment.

Two long-snouted weevils (Curculio species) are the main insect pest of home chestnut crops. The adult drills through the developing burr and lays eggs inside the nut; the grub eats the kernel and then chews its way out after the nut has fallen, leaving a neat round hole and burrowing into the soil to pupate. Infested nuts often look perfect when gathered and reveal themselves in the kitchen or in storage a week later, which is why sorting and prompt refrigeration matter so much. Populations build year on year in an orchard where fallen nuts and burrs are left on the ground.