What's eating my japanese chestnut?

Japanese chestnut is highly resistant to chestnut blight and, like Chinese chestnut, is key to blight-resistance breeding programs. Its main pest threats are the oriental chestnut gall wasp, chestnut weevil, and chestnut moth caterpillars, all targeting the nuts. Squirrels compete at harvest. In Japan, the chestnut gall wasp has historically devastated unprotected crops.

Galls on new buds prevent shoot extension and completely suppress nut production on affected branches; a single infestation can eliminate an entire season's crop. Biological control with parasitic wasp Torymus sinensis is the proven method in Japan and Europe; report new infestations to authorities; use gall-wasp-resistant varieties where available.

Larvae tunnel through the kernel; infested nuts drop early with exit holes; stored nuts with undetected eggs later become worm-riddled. Daily collection and destruction of fallen nuts; hot-water treatment at 50°C for 45 minutes before storage; soil cultivations to kill pupae.

Caterpillars bore into ripening nuts and consume the kernel; damage is only visible when the nut is opened. Pheromone traps to time sprays; pyrethroid or spinosad at peak moth flight; collect and destroy fallen nuts promptly.