Eastern Black Nightshade (Solanum ptycanthum) Interference in Processing Tomato (Lycopersicon esculentum)

Abstract

In replacement experiments in the greenhouse, plant relative yield (PRY) of both eastern black nightshade and tomato increased as the proportion of nightshade plants increased in the pots, indicating that nightshade is less competitive than tomato. In field studies tomato yield was reduced by two-thirds if three nightshade plants m–1of row were allowed to grow with tomato more than 6 weeks following tomato establishment The percent marketable fruit decreased linearly from 73% with no nightshade to 49% when nightshade were present for 12 weeks. When nightshade and tomato were transplanted together, tomato yield was 9000 kg ha–1and 49% of the fruit was marketable, while tomato yields were 30 000 kg ha–1and 70% of the fruit was marketable when nightshade was established 9 weeks after tomato planting.