141 Weed Technology. 2005. Volume 19:141–147 Factors Affecting Sprouting and Glyphosate Translocation in Rootstocks of Redvine (Brunnichia ovata) and Trumpetcreeper (Campsis radicans) 1 DEMOSTHENIS CHACHALIS and KRISHNA N. REDDY 2 Abstract: Greenhouse and growth chamber experiments were conducted to investigate the sprouting potential of rootstock; the effect of temperature, burial depth, and length of rootstock on sprouting; and the effect of shoot removal on resprouting ability of rootstock in redvine and trumpetcreeper. Glyphosate translocation along the rootstock of redvine was also measured. Higher sprouting was observed at 20 to 40 C in trumpetcreeper (60 to 73%) and at 30 to 40 C in redvine (45 to 47%) compared with other temperatures. Redvine sprouting was totally inhibited at 15 C, whereas trum- petcreeper had a sprouting of 12%. Emergence of shoot from a 28-cm planting depth was completely inhibited in redvine, whereas trumpetcreeper had 23% sprout emergence. After shoot removal treat- ments applied every 3 wk, redvine rootstock segments 2 cm long were totally depleted after fifth shoot removal treatment (15 wk after planting [WAP]). In trumpetcreeper, total depletion was not reached by 15 WAP, regardless of rootstock length. 14 C-glyphosate was translocated from the treated shoot attached to the apical end of a 35-cm rootstock to the untreated end with slightly less 14 C- glyphosate recovered at the untreated end compared with 5 to 10 cm from the treated shoot. These results indicated that vegetative reproduction in redvine is more sensitive to cool temperatures, deep burial depth, and short rootstock segment than trumpetcreeper. Variable control of redvine with glyphosate could be due to inadequate herbicide translocation within the rootstock. Nomenclature: Glyphosate; redvine, Brunnichia ovata (Walt.) Shinners # 3 BRVCI; trumpetcreeper, Campsis radicans (L.) Seem. ex Bureau # CMIRA. Additional index words: Absorption, regrowth, sprout regeneration, uptake. Abbreviations: DAT, days after treatment; WAP, weeks after planting; WAT, weeks after treatment. INTRODUCTION Redvine and trumpetcreeper are native perennial fast- growing woody vines that climb on any support and oth- er vegetation or trail along the ground. They are found in cultivated fields, wastelands, yards, fencerows, river- banks, right-of-ways, and forests. In cultivated fields, their infestations may range from spotty to severe. Red- vine and trumpetcreeper are among the 10 most trouble- some weeds in cotton (Gossypium hirsutum L.), soybean [Glycine max (L.) Merr], and corn (Zea mays L.) in the midsouthern United States (Webster 2000, 2001). They are difficult to control because they can propagate from a deep and extensive root system (Elmore 1984). Red- 1 Received for publication January 14, 2004, and in revised form June 30, 2004. 2 Postdoctoral Research Associate and Plant Physiologist, Southern Weed Science Research Unit, United States Department of Agriculture, Agricultural Research Service, P.O. Box 350, Stoneville, MS 38776. Current address of senior author: Weed Scientist, Greek National Agricultural Research Foun- dation (NAGREF), Plant Protection Institute of Volos, P.O. Box 303, Volos 380 01, Greece. Corresponding author’s E-mail: dchachalis.ippv@nagref.gr. 3 Letters following this symbol are a WSSA-approved computer code from Composite List of Weeds, Revised 1989. Available only on computer disk from WSSA, 810 East 10th Street, Lawrence, KS 66044-8897. vine and trumpetcreeper produce numerous seeds in non- cultivated areas such as ditches, roadsides, and fence- rows (Chachalis and Reddy 2000; Shaw et al. 1991), and seeds serve as means of propagation and spread into new areas. However, the rapid increase in plant numbers after initial establishment is mainly attributable to the regen- erative capability of rootstocks (propagule production) due to numerous adventitious buds (Elmore 1984). The effects of factors such as temperature, burial depth, and size of the root segment on regenerative capacity of red- vine and trumpetcreeper are not known. Herbicides (e.g., acifluorfen, lactofen, paraquat) that are active on these weeds kill only top growth and have little or no effect on the rootstock (Chachalis et al. 2001; Reddy and Chachalis 2004). Desiccation of foliage is temporary, often partial, and new sprouts arise from un- derground rootstocks (Chachalis et al. 2001; Reddy and Chachalis 2004). Dicamba or glyphosate applied in the spring or fall either to a fallow field or after crop harvest can reduce redvine and trumpetcreeper (DeFelice and Oliver 1980; Edwards and Oliver 2001; Elmore et al. 1989). Glyphosate can be used to control these perennial