SA Animal & Plant Control Commission GPO Box 1671 Adelaide SA 5001
SA Animal & Plant Control Commission Box 618 Naracoorte SA 5271
Summary. Herbicides reduce one-leaf and two-leaf cape tulip, Homeria flaccida and H.miniata, in non- arable permanent pastures however increased yields may not cover control cost. Sprayed herbicides give good control, but reduce desirable pasture species. Carpet roller applicators are effective on one leaf cape tulip. The recommended treatment is using a contra-rotating carpet roller to wipe a solution of glyphosate (45 g a.i./L water) or metsulfuron-methyl (60 mg a.i. /L water) with an organosilicone surfactant (2 mL/L) from flower-stem emergence until flowering.
Cape tulip is a weed of non-arable pastures in southern Australia. There are limited control options. Phenoxy herbicides are useful (2) but may damage nearby crops. We tested ways for farmers to manage cape tulip, in pastures in South Australia.
In field trials from 1981 until 1991 we tested herbicides and application methods for cape tulip control. All trials were in randomised block design in permanent pasture. European Weed Research Council (EWRC) scoring system was used for visual assessment (1).
At Clare. on one- and two- leaf cape tulip. we treated 4 replicates with the herbicides shown on Table 1 at two times. Plots were 20x3 m. Treatments were applied by a 1.7 to wide hand boom, with spray volume of 166 IJha. Table 2 shows a similar experiment sprayed in 1983. A third trial shown in Table 3, evaluated a wiper.
Table 1. Effect of herbicide timing on the control of one-leaf cape tulip at Clare.
Table 2. Effect of sulfonyl-urea herbicides on one and two leaf cape tulip at Clare.
Table 3. Effect of pipe rope-wick wiper applied glyphosate on cape tulip at Clare.
we applied 'Lug giypnosate iso-propyiamme tormulatea witn surfactant) witn a iivan pipe rope-wick wiper, set 3-10 cm from desirable pasture, with two passes at opposite directions at 6 km/hr. We applied 2,4-D and amitrole by boomspray in 70 L/ha spray volume, with plots 200x 10 m replicated three times.
Eden Valley site
At a site with two-leaf cape tulip, we sprayed herbicides listed in Table 4, with a 2.8 m boom at 100 IJha. We wiped glyphosate with a Winstone Wick Wiper one or two times.
Table 4. Cape tulip and pasture regeneration one year after treatment at Eden Valley.
Mount Benson site
At Mount Benson, we sprayed the herbicides listed in Table 5 onto one-leaf cape tulip in 1987. The four replicates included plots 2x25 m. In 1988 half the plots were retreated. We burnt another area in autumn 1988 to improve sprouting or dormant corms (3) and applied the same treatments in spring.
Table 5. Effect of herbicides on one-leaf cape tulip with and without burning.
On an area burnt in autumn 1989, we applied 45 g/L glyphosate or 60 mg/L metsulfuron-methyl with 2 mL/L organosilicone surfactant (Pulse()) by contra-rotating carpet roller. Plots were 20x4 m. The herbicide was applied in either a single or double pass at two speeds at times shown in Table 6. Approximately 10 L/ha of solution was applied. Pasture samples were hand cut on 28 August 1990, separated from cape tulip and oven dried to measure dry matter production. All means were compared using a t-test.
Herbicides reduce cape tulip counts in permanent pastures however increased yields may not cover control cost. Sprayed herbicides give good control, but reduce desirable pasture grasses and legumes (data not shown). Ropewipers are difficult to maintain and unreliable. Carpet roller applicators are effective on one-leaf cape tulip. The best treatments use a contra-rotating carpet roller to wipe a solution of glyphosate (45 g/L water) or metsulfuron-methyl (60 mg/L water) with an organosilicone surfactant from flower-stern emergence until flowering. Burning in autumn improves control (Table 5). At Clare both one and two leaf cape tulip were assessed separately, but arc reported together here in Tables I, 2 and 3.
The wiper technique was as effective as sprayed herbicide at Clare (Table 3) and Eden Valley (Table 4). Wiping reduced pasture damage. Reduced speed or double wiping did not improve control except for double wiped early treatments at Mt Benson (Table 6). Glyphosate, or metsulfuron, applied by wiper protected the pasture, and gave good control of one and two leaf cape tulip at all sites.
Depending on application method and timing, glyphosate, chlorsulfuron and metsulfuror. methyl are equal or more effective than butoxyethyl ester 2,4-D, or amitrole. Pasture damage with sprayed glyphosate, chlorsulfuron or amitrol is too severe for practical use.
Timing of herbicide
Timing of herbicide treatment is critical. From Tables I and 2, early treatment, prior to bulb exhaustion, is best for sprayed chlorsulfuron, metsulfuron, 2,4-D, and amitrole. Wiping was more effective at stem emergence or flowering, probably due to smaller leaf area at earlier times.
Table 6. Effect of timing and herbicide on one-leaf cape tulip at Mount Benson.
Pasture production, excluding cape tulip from treated plots (Table 6) was less than from the untreated plots. The dry matter from plots increased with cape tulip plants (R2=0.666), from 35.7 g/m2 where cape tulip was totally removed, to 119 g/m2 at the highest cape tulip density (data not shown). This highlights the need to resow pastures after cape tulip is reduced.
Farmers should include cape tulip control in a general pasture improvement strategy, including resowing suitable species. The increased pasture production from cape tulip removal may not cover control costs without resowing. Farmers in SA are adopting these strategies.
1. Australian Weeds Committee, 1979. Guidelines for field evaluation of herbicides, (AGPS:Canberra) ppA1/1-4
2. Parsons. W.T. & Cuthbertson, E.G. 1992. Noxious Weeds of Australia. (lnkata:Melbourne) pp. 7479.
3. Pearce, G.A. 1963. Weed Research 3.215-229.