Variations in Seed Production and the Response to Pests of Morningglory (Ipomoea) Species and Smallflower Morningglory (Jacquemontia tamnifolia)
Flowering dates, seed production, and disease and insect susceptibility of sevenIpomoeaspp. and smallflower morningglory [Jacquemontia tamnifolia(L.) Griseb.] were determined under field conditions in 1973 and 1974. Seed produced per plant were as follows: ivyleaf morningglory [Ipomoea hederacea(L.) Jacq.], 6000; entireleaf morningglory [I. hederacea(L.) Jacq. var.integriusculaGray], 5000; pitted morningglory [I. lacunosaL.], 10000; wild tall morningglory [I. purpurea(L.) Roth.], 26000; commercial tall morningglory [I. purpurea(L.) Roth ‘Crimson Rambler′], 15 000; cypressvine morningglory (I. quamoclitL.), 9000; cotton morningglory [I. trichocarpaEll. var.torreyana(Gray) Shinners], 9000; palmleaf morningglory (I. wrightiiGray), 7000; and smallflower morningglory, 11000. Seed weights were about 29, 26, 22, 21, 19, 13, 19, 37, and 5 mg/seed, respectively. Pitted morningglory appeared to have a qualitative short day-length requirement for flower initiation and the other species appeared less day-length sensitive. Ivyleaf morningglory and entireleaf morningglory were highly susceptible to orange rust [Coleosporium ipomoeae(Schw.) Burrill] and white rust [Albugo ipomoea panduratae(Schw.) Swingle], but the otherIpomoeaspecies were only slightly susceptible and smallflower morningglory was resistant. Cotton bollworms (Heliothis zeaBoddie) and cabbage loopers (Trichoplusia niHubner) fed preferentially on ivyleaf morningglory and entireleaf morningglory.