What's eating my potato?

Potatoes face serious threats from Colorado potato beetles, aphids, and wireworms underground, plus slugs in wet conditions. Animals including deer and rabbits browse the foliage. The Colorado potato beetle is the most destructive pest worldwide, capable of defoliating entire plants if populations go unchecked early in the season.

Yellow-and-black striped adults and orange larvae strip leaves from the plant top-down; repeated defoliation kills plants and reduces tuber yield. Hand-pick eggs, larvae, and adults daily; apply Spinosad or neem oil for heavier infestations; rotate crops each year to break the life cycle.

Colonies on leaf undersides cause yellowing, curled leaves, and sticky honeydew; critically, they vector potato virus Y and leafroll virus, causing greater crop losses than the feeding itself. Blast off with a strong water jet; introduce ladybirds or lacewings; use insecticidal soap or pyrethrin sprays; remove heavily infested stems.

Slender, tough yellow-orange larvae tunnel into seed tubers and developing potatoes, leaving narrow bore holes that invite rot and render tubers unsaleable. Avoid planting in recently broken-up grassland; use biopesticide Steinernema kraussei nematodes; rotate with brassicas or legumes; trap with buried carrot pieces to monitor levels.

Surface slugs eat young foliage at night; keeled slugs tunnel deep into tubers at harvest, leaving ragged cavities and slime trails inside the flesh. Apply iron phosphate pellets around plants; encourage ground beetles and hedgehogs; use copper tape on raised beds; harvest promptly when foliage dies to minimise tuber exposure.