Studies were conducted to evaluate seed and root reproduction and herbicide sensitivity of maypop passionflower (Passiflora incarnata L. ♯ PAQIN). Water-leached seeds that were not exposed to light had the greatest germination (53%). Depending on soil type, seedlings emerged from depths of 10 to 12 cm. Most rapid germination and seedling development occurred between 30 and 35 C. Plants rapidly produced an extensive system of lateral roots and rhizomes that had regenerative capability at maturity. Root or rhizome sections of only 0.5 cm in length had a 20% regeneration rate. Desiccation effectively reduced viability of root and rhizome pieces. Effective herbicide control was limited to the triethylamine salt of triclopyr {[(3,5,6-trichloro-2-pyridinyl)oxy] acetic acid} at 2.2 ai kg/ha, alkanolamine salt of 2,4-D [(2,4-dichlorophenoxy)acetic acid] at 1.7 kg/ha, and dicamba (3,6-dichloro-o-anisic acid) at 0.3 to 0.6 kg/ha.

Studies were conducted to investigate the reproductive biology and herbicide response of horsenettle (Solanum carolinense L. # SOLCA) and robust horsenettle (Solanum dimidiatum Raf. # SOLDM) that are common in peanut (Arachis hypogaea L.) production. Of these two species, horsenettle had a higher rate of seed germination, greater ability for seedling establishment in a competitive situation (pasture), greater ability to regenerate from smaller root fragments, and greater ability to regenerate from progressively greater depths in soil. Horsenettle was relatively more sensitive to glyphosate [N-(phosphonomethyl)glycine] (1.1 and 2.2 ai kg/ha), propylene glycol butyl ether esters of 2,4-D [(2,4-dichlorophenoxy)acetic acid] (0.8 and 1.7 ae kg/ha), and the ethanolamine salt of 2,4-D (1.7 ae kg/ha) than robust horsenettle. Conversely, robust horsenettle was more sensitive to dicamba [3,6-dichloro-2-methoxybenzoic acid)] (0.3 and 0.6 ae kg/ha). In a field study, dicamba applied annually in July or August for 2 yr at a rate of at least 1.1 kg/ha controlled 92% or more.