Pests and Trouble

A healthy, well-spaced plant shrugs off a lot. What it cannot shrug off is wet foliage, a hornworm you did not pick, or blight moving in from last year’s vines. Hand-picking and sanitation outperform most sprays in a home garden.

Hornworms

Fat green caterpillars that strip a stem overnight. Look for dark droppings, then the worm. Hand-pick into soapy water. If you see white cocoons on its back, leave it — braconid wasps are already in the bed.

Aphids and whiteflies

Blast with water, then soap if needed. Nasturtiums as a trap help. Avoid broad insecticides that kill the hoverflies and lady beetles you want.

Early blight

Target-spot lesions on lower leaves, working up. Mulch, water at the soil, prune the bottom foot of leaves, and do not compost diseased vines. Resistant hybrids help in humid zones.

Late blight

A cool, wet-weather killer of tomatoes and potatoes. Greasy lesions, white fuzz, collapse. Remove plants in a bag. This is why those two crops do not share a bed.

Blossom-end rot

A leathery black patch on the bottom of the first fruit. Calcium cannot move when water is erratic. Even out irrigation; do not lime in a panic unless a test says pH is low.

Cracking and catfacing

Rain after drought splits skins. Mulch and steady water. Catfacing is cold at bloom — ugly shoulders, still good to eat. Save seed from smooth fruit if you are keeping a line.