Disease Suppression on Greenhouse Tomatoes Using Plant Waste Compost

Abstract

This study investigated the disease suppression abilities of a compost amendment that was added to the conventional growing medium, yellow cedar sawdust, used in most British Columbia vegetable greenhouses. The compost amendment was produced in a controlled, in-vessel process primarily from greenhouse crop waste materials. The pathogen and cultivar under study were Fusarium oxysporumf. sp. radicis-lycopersici (FORL) on Dombito (FORL-susceptible) beefsteak greenhouse tomatoes. Significant reduction of Fusarium crown and root rot was also realized in tomato seedlings by applying compost amendment from several different batches, as a seed cover or plug substitute. In a greenhouse trial, disease suppression using a mixture of 2:1 sawdust to amendment by volume was shown to be most effective. As a result, the tomato yield over a nine-month growing season was improved by 74% where the medium was deliberately infested with FORL.

Keywords:

• Compost
• Disease suppression
• Greenhouse
• Tomato
• Waste.

Notes

⁺Location—pathology greenhouse; temperature—18–25°C; lighting—18-h photoperiod, sodium vapor lamps; inoculation—4 days from seeding; scoring times (days from seeding)—21, 28, 35, 42 & 50 days with 5–6 replicates each; tray plug type—keem plug (2.5 cm dia. cylinder); trays per treatment—2.

*There were at least 30 plants per treatment total, of which 15 were included in the scoring results.

⁺Location—growth chamber; temperature—24°C (first 2 weeks); 23°C (subsequent); lighting—18-h. photoperiod, fluorescent grow lights (after germination); inoculation—8 days from seeding; scoring times (days from seeding)—46 & 53 days with 14—17 replicates each; tray plug type—small cube, 4 cm; trays per treatment—3.

⁺Location—growth chamber; temperature—24°C (first 2 weeks); 23°C (subsequent); lighting—18-h. photoperiod, fluorescent grow lights (after germination); inoculation—7 days from seeding; scoring times (days from seeding)—48 days with 28 replicates each; tray plug type—small cube, 4 cm; trays per treatment—2.

*Scores range from 1 to 5, with 1: white, healthy roots; no sign of disease; 2: slight browning of vascular tissue in the crown; 3: extensive browning of vascular tissue in the crown; 4: extensive necrosis of the crown; and 5: dead plant with typical symptoms of crown and root rot.

*Scores range from 1 to 5, with 1: white, healthy roots; no sign of disease; 2: slight browning of vascular tissue in the crown; 3: extensive browning of vascular tissue in the crown; 4: extensive necrosis of the crown; and 5: dead plant with typical symptoms of crown and root rot.

*Does not include plant 4A-1.