Canadian producers grow both field and greenhouse tomatoes. Field tomatoes are used for processing and as table tomatoes, while greenhouse varieties are grown only for fresh consumption. Most tomatoes are grown in Ontario, BC and Quebec with only minor commercial production across the remaining provinces. While variations in weather are a critical factor in determining yield and fruit quality, disease and pests can be just as important in achieving an abundance of ripe, red fruit.
Prevention is key to disease management
The warm, moist conditions that help tomatoes grow also allow disease to thrive. Tomatoes share many of the same disease issues as potatoes, such as early and late blight. Other diseases, like anthracnose are easily spread through splashing water. Planting clean, certified seed with a good disease resistance package can help keep disease at bay. Frequent scouting, removal of infected material, elimination of host weeds and proper nitrogen application can all help reduce risk. Fungicides need to be applied preventatively to be effective in eliminating these diseases.
Eliminate both grassy and broadleaf weeds
Prior to emergence, broadleaf weeds can delay the plant from establishing and also provide competition for growth. Most tomato growers are able to address broadleaf weeds such as redroot pigweed and lamb’s quarters with a pre-emergent herbicide, along with inter-row cultivation. Perennial weeds such as quackgrass and other annual grassy weeds can be managed in the early stages of growth with a post-emergent herbicide application. Tomato producers should be aware of pre-harvest intervals when choosing a crop protection product.
Watch for insects throughout the season
Aphids can be present in tomato crops throughout the season, but they can rapidly multiply when the weather turns hot and dry. Growers should monitor their fields for aphids over several weeks to see if populations are increasing. Aphids can also be a vector for viral disease. Cutworms are a concern early in the season as they will feed on the plant stems, cutting them off at the soil and leaving the plant to wilt and die. An insecticide can be effective, but only when the cutworms are young and small.