Submitted to: Weed Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/6/2007
Publication Date: 7/1/2007
Citation: Bryson, C.T., Byrd, J.D. 2007. Biology, Reproductive Potential, and Winter Survival of Tropical Soda Apple (Solanum viarum). Weed Technology 21:791-795. Interpretive Summary: Tropical soda apple is an invasive Federal Noxious Weed that continues to spread at an alarming rate in the southeastern United States. Research determined that tropical soda apple seeds can germinate from green and ripened fruits depending on the fruit size and maturity. Seeds exposed to winter temperatures within intact mature fruits exhibited higher levels of germination than mature exposed seeds. All tropical soda apple plants established by late spring and early summer produced fruits and viable seeds by frost and some tropical soda apple plants were able to survive winter conditions from rootstocks as far north as Stoneville, MS. Winter survival of seeds and rootstocks should be taken into account in developing best management practices for tropical soda apple control.
Technical Abstract: Field and greenhouse studies were conducted from 1996 to 2000 to determine tropical soda apple fruit size required for mature seed, overwintering survival potential of seeds, growth and fruit production, and a combination of late summer clipping followed by herbicides on overwintering potential of mature tropical soda apple plants in a containment area near Stoneville, Mississippi (latitude 33o 25’ N). Seedling emergence was greater than or equal to 50% from tropical soda apple fruit greater than 1.8 cm diameter. Tropical soda apple overwintering emergence was 14, 10, 48, 42, and 13% from seed alone and 86, 83, 48, 41, and 18% for seeds in tropical soda apple fruit overwintering at 100, 0, -5, -10, and -15 cm from the soil surface, respectively. Prior to frost (early Nov), tropical soda apple plant heights were 0.8, 0.6, and 0.7m; plant diameters were 2.6, 1.7, and 2 m; fruit produced per tropical soda apple plant were 415, 342, 128; and plant weights were 9.9, 9.5, and 4.9 kg at 27 weeks after transplanting (WATP) for 1996, 1997, and 1998, respectively. Regeneration from overwintering tropical soda apple roots varied depending on the winter conditions. These results suggest that tropical soda apple plants can survive mild winters.