What's eating my hosta?

Hostas are famous slug and snail magnets — these molluscs shred the large leaves overnight, leaving characteristic ragged holes. Deer and rabbits graze foliage down to stumps in a single night if unprotected. Vine weevil larvae attack roots, and foliar nematodes cause brown streaking between the leaf veins. Slugs are by far the most universal and serious threat.

Ragged holes across leaf blades, often large enough to ruin the display; silvery slime trails on soil and foliage; worst in wet springs. Apply iron phosphate pellets (pet-safe) at emergence; use copper tape around containers; lay grit or sharp sand mulch; hand-pick at night. Nematodes (Phasmarhabditis hermaphrodita) are effective applied to moist soil.

Entire leaf stems browsed off cleanly at ground level overnight; recurring damage prevents plant from recovering or building energy reserves. Erect physical fencing or individual wire cloches; apply deer repellent sprays (reapply after rain); grow in a walled or fenced garden where possible.

Adults notch leaf edges in a distinctive scalloped pattern at night; larvae in soil devour roots, causing plants to wilt and collapse. Apply pathogenic nematodes (Steinernema kraussei or Heterorhabditis bacteriophora) to moist soil in late summer; check and bin grubs when lifting and dividing hostas.

Brown or tan streaks between leaf veins, following the vein pattern exactly; tissue dies from the base of the leaf upward; spreads in wet conditions. Remove and bin (do not compost) all affected leaves; avoid overhead watering; there is no chemical cure available to home gardeners — strict hygiene is essential.