The Tomato as an outdoor crop is, like its relative the Potato, a creature of the weather. Given a dry, warm season, the plant sets and swells abundance of fruit, if the cultural treatment is correct. In wet, chilly years it often falls a prey to Phytophthora. It is a great thing to get the plants along early and strong. If the blight show itself, spray with Bordeaux Mixture.
This disease manifests itself by yellow spots on the leaves, usually accompanied by brown patches on the under side. It is more common on indoor than on outdoor plants, and is very liable to occur when the atmosphere under glass is muggy. Free ventilation in damp weather, with a little warmth in the pipes if chilly, and spraying with Bordeaux Mixture at the first sign of an attack, represent the best preventive measures.
Apparently healthy Tomato plants sometimes wilt suddenly, erstwhile fresh, substantial leaves hanging limp and lifeless. Rich animal manures should be avoided, and burnt refuse added to the soil. Care should be exercised in watering. The soil should be kept just moist, neither sodden nor dust dry. It is important to get seed from a healthy source. Veltha may be applied if an attack threatens to develop.
A small, rapidly flitting white fly named Aleyrodes vaporariorum sometimes infests Tomatoes under glass. It is a troublesome pest if allowed to spread, and it is well worth while to hunt down and kill the first insects seen. Should it threaten to become master of the situation sulphur-wash the hot-water pipes and turn on the heat.