Blossom End Rot

Rot starts as a small, water-soaked area at the blossom end which darkens and enlarges until fruit ripens. It is caused by undesirable environmental conditions, principally drought stress or excessive nitrogen fertilizer. Interior blossom end rot causes browning inside the fruit.

Control
Maintain uniform moisture conditions throughout the growing season and avoid excessive nitrogen. Foliar applications of calcium chloride or calcium nitrate are rarely beneficial.

Blotchy Ripening

Symptoms are irregular fruit ripening. It is caused by a variety of cultural conditions and there is no known control. It has been linked to potassium or boron deficiency and to high nitrogen levels which favor excessive growth.

Control
Follow a well-balanced fertilizer program. Some varieties appear to be less susceptible than others.

Boron Deficiency

Young plants show purple stems and petioles. Growth is slow. On mature plants, fruits show coarse brown russetting, distortion and cracking on russetted areas.

Control
For ground application rates, see table under “Boron”, Nutrient Management section of this guide. For foliar application, spray plants during June with Solubor at 1.1 to 1.7 kg/ha (0.4 to 0.7 kg/acre) in 1,000 L/ha (400 L/acre) of water. Foliar applications are preferable where beans or cucumbers are likely to follow tomatoes.

Chemical Fruit Ripening

Use Ethrel for uniform ripening for once-over harvest and to enhance ripening in late varieties or during late seasons or when ripening is delayed. Apply when 5 to 30 percent of the fruit is red or partly red. The key to good results is good coverage. Use 3.75 to 6.4 L/ha (1.5 to 2.6 L/acre) in 30 to 500 L/ha (12 to 200 L/acre) of water. Use the higher rate when day temperatures are less than 18°C and tomato growth is dense. Harvest fruit at proper maturity, generally 14 to 21 days after treatment. Observe treated fruit frequently for condition of crop. Cool temperatures can slow colour development and extend period between treatment and harvest. Fruit does not appreciably increase in size after Ethrel treatment.