Wetland Nightshade (Solanum tampicense) Growth Response to Temperature, and Winter Survival, in Relation to Potential Spread

Greenhouse, growth chamber, and winter survival studies were conducted at Stoneville, MS from 1996 to 2002 to determine growth, time to first flower, and winter survival of wetland nightshade. At 12 wk after emergence, wetland nightshade plants had 58-, 45-, 48-, and 4-cm heights, respectively; 24, 21, 21, and 12 nodes/plant, respectively; 62, 31, 36, and 21 leaves/plant, respectively; and 7.1, 3.9, 5.1, and 0.3 g/plant dry weights, respectively, at temperatures of 26/36, 20/30, 14/24, and 8/18 (±0.5) C at the 14/10 day/night length. Flowering occurred at 79, 85, and 85 days after emergence at 26/36, 20/30, and 14/24 C night/day, respectively at the 14/10 day/night cycle. Wetland nightshade plants did not flower at 8/18 C. Wetland nightshade growth was adequate for flowering and fruit production in additional areas of the southeastern United States with night/day temperatures greater than or equal to 14/24 C. Winter survival was greater than or equal to 33% for established wetland nightshade plants in 5 of 6(1996 to 2002) above water levels and 82% from 20 cm below the water surface. Based on these results, wetland nightshade has the potential to continue to spread in the United States.