Also Bordeaux mixture. More of a problem with greenhouse tomatoes when grown cool in humid conditions. Raise heat, reduce humidity. Mulch plants, sterilize soils. Well drained, sterile soil for sowing is the key to control.
Affected leaves turn brown, drop.
Also Bordeaux mixture. One of the most common and damaging diseases. Generally not damaging unless soil and air temperatures are high in much of the season. Slight yellowing of a single leaf, or slight wilting of the lower leaves is followed by an overall yellowing. Brown discoloration of vascular tissues in stem or petioles of wilted leaves is common.