6 Australian Weeds Dec. 1981

Studies on rubber vine (Cryptostegia grandiflora): furfuryl ester; picloram as the acid. and triclopyr as the ethyleneglycol but yl et her III Basal bark application of phenoxyalkanoic acid (EGBE) ester (as Doweo 233. M 4021 ). herbicides Trial I The eight herbicide esters and one oil -soluble acid formulation listed G. J. Harvey in Table I all di ssolved in diesel distillate Department of Land s, Sherwood, Oueensland 4075 at 5% and 2% a.e. concentrations with and without 1% dibutyJ phthalate. were applied in 10-microlitre droplets to the basal 2.5 cm of stem of 1600 rubber vine seedlings. Four diese l distillate controls. al so with and without 1% dibutyl phthal­ ate. were included . The experimental design was a ran­ Summary Materials and methods domi zed block design with 40 treatme nt s (8 herbicid es x 2 conce ntrations + 4 Rubber vine (Cryptostegia gralldif/ora) Rubber vi ne seedli ngs were grown in a diesel distillate controls x 2 factors. with is a serious weed of grazing lands in glasshouse in individual nursery seedling and without 1% dib utyl phthalate). fi ve north Queensland. A research pro­ tubes (7 cm hi gh x 4.5 em diameter) replicates and ten plants per pl ol. Treat­ gramme aimed at improving existing using commercial potting mixes. Freshly­ ment s were assessed four months after recommendations for chemical con­ collected rubber vine seed has a germi­ application, by whi ch time those plants trol of rubber vine was commenced in nation rate greater than 95%. and at sum­ not killed by the treatment s were show­ 1977 and this paper presents data from mer temperatures (33°C day/20°C night) in g early s igns of recovery. two glasshouse trials. In one trial, di­ germination is complete within seven to Plant counts were converted to per­ camba acid and dicamba, 2,4-D, 2,- ten days. Plants used in these experi­ centage mortality figures and the data 4,5-T and triclopyr ester formulations ment s were approximately nine months subjected to analysis of variance and a (but not dichlorprop or fenoprop ester old. about 30 cm tall with basal stem factorial analysis using inverse si ne formulations) were very effective diameter of 0.5 em. transformed data. against rubber vine when applied as The fo ll owing herbicides were used solutions in diesel distillate to the basal in these trials: 2.4-D. as the eth yl ester Trial 2 2.4.5-T butyl/isobutyl esters . section of the stem . Adding dibutyl (as Farmeo 0 -80) ; 2.4.5-T as the acid 2.4.5-T acid , di camba acid and picloram phthalate to these solutions did not and mi xe d bu tyl/isobutyl esters (as acid in diesel distillate, with and without alTect the results. In a second trial, Farmeo T-80); dichlorprop as the iso­ I % wetting agellt (calcium dodecylben­ basal bark application of picloram, octyl ester; fenoprop as the butoxycthyl zene sulphonate) were appl ied as 10- dicamba and 2,4,5-T acids and 2,4,5-T and mi xed butyl/isobut yl esters (as microlitre droplets to the basal 2.5 cm ester solutions in diesel distillate, with Farmco TP-70); dicamba as the acid and of stem o f 768 rubber vine seedlings at and without I % calcium dodecylben­ zenesulphonate wetting agent, were effective. Picloram and dicamba were more effective than 2,4,5-T, while a 2,4,5-T ester formulation was more elTective than 2,4,5-T acid. Addition Table I Herbicides used in Trial and results. in ranked order of the wetting agent was without elTect.

Treatments Mortality Arc~ine Introduction (%)' transformed data

Rubber vinc (CrY{JIO.\"Ie~ ia grwu/ij7ora R.Br.) is a scrious weed of grazin g lands dicamba ac id. 5% 100 1. 5708 in north Queensland . Concern about it s dicamba. furfuryl cster. 5% 100 1.5708 prese nce and spread was ex pressed be­ tridopyr. EGBE ester. 5% 100 1.5708 fore 1923 (White. 1923) and has contin­ 2.4-0 . ethyl ester. 5% 100 1. 5708 dicamba acid . 2% tOO 1. 5708 ued to be expressed to the prese nt dicamba. furfuryl ester. 2% 100 1.5708 (Caltabiano. 1973). Declaration of rub ­ triclopyr. EGBE ester. 2% 100 1. 5708 ber vi ne as a noxious weed occurred in 2.4-0. ethyl ester. 2% 99.2 1.4806 1955 under the SlOe/.: ROllles lIlId Ru ral 2.4.S-T. butyl/isobut yl esters. 5% 99 .2 1.4806 LaHds Pro fc'ef;oll A ct.\" and has led to a 2.4.5-T . but yl/isobutyl esters. 2% 99 .2 1.4806 greater awareness of the problems that fenoprop. butoxyethyl ester. 5% 98.2 1. 461 3 it causes. Many landho ld ers regard fenoprop. butyl/isobutyl esters, 5% 98 .8 1.4613 c urrently-available chemical control fenoprop. butoxyethyl ester, 2% 9 1.2 1. 2698 methods as unreliable o r prohibitively fenoprop. butyl/isobutyl esters. 2% 80.8 1. 11 72 dichlorprop. iso-octyl ester. 5% 70.5 0.9968 expensive. dichlorprop. iso-octyl ester. 2% 5 1.0 0.7955 Under these circumstances. a research diesel distillate 0.7 0.0823 programme aimed at achieving more re­ li able chemical comrol of rubber vine L.S.D. I% 0.3475 was commenced in 1977 (Harvey. 1981). 5% 0.2620 This paper reports the results of two glasshouse trials .which are part of this , There w~re nn differences be tw een treatme nt s with and wilhnur lIibut)' 1 phrhalatl'. M) rh~ dara WCI"(' lu mped til giv e five programme. repticatcs (I f 20 plams per tre atmen!. Mon alit)' figu res given are thl' me an values (If ,he fi ve repl icates. Aus tralian Weeds Dec . 1981 7 concentrations of 5%. 1%. 0.5% and (S %) herbicides are used. while larger to rubber vine (Harvey. 198 1) . How­ 0. 1% a.e. volumes (approximately 50 microlitres) ever. the data obtained in these experi­ The experimental design was a raJl ­ of more d ilute (0 .5 to 1.0%) solutions ment s all ow 110 explanatio n of these domized block dcsign with 32 treatments are used in the fie ld . resu lt s. (4 herbicides x 4 concentrations x 2 Fro m Table I it can be seen that factors. with and without wetting agent ), 2.4-D. 2A.S-T. dicamba and triclopyr four replicates and six plants per plot. are ve ry effective aga in st rubber vine. Assessment and analysis were the same whil e the propionic acid analogue s of References as for Trial I . except that untransformed 2.4-0 and 2.4.5-T (i.e. dichl orprop and Beger. H. W . ( 1969). Effects of2.4.5-T and data were used in the analyses. fenoprop) are not. dibu1 yl ph thalate on blood wood (Eucalyp' Robert son ( 196S) reported 'rumn"rs ' IuS dh·/woll lOphh,;a). QIf('('II.'i/oll(l j (J/il'lllll that phthalic acid and dimethyl phthalate of Agricultural lind AI/ill/al Sch,I1t't's Results enhanced bark penetnlt ion and hence. it 26( I): t t 7-20. Results of the analyses of variance o f is implied. the efficacy of basal bark Caltabiano. G. ( 1973) . Rubber vin e (CrYfJ - data in Table 2 were: (i) the wetting agent herbicide treatment s. These rumours 1O.\·legill gralllfij7om) in north Queensland . Queensland Department of Lands Report . had no signiticant effect on the results; persist and were the reason for the in ­ (unpubli shed) (ii) 2.4.5-T ester was more e ffecti ve than clusion of d ibutyl phthalate treatments Harvey. G. J. ( 198 1). Siudies on ru bber vine 2.4 .S-T acid (P < O.OS) ; and ( iii) in this experiment. The resulrs of these (Cryp lOsl('~ill grlllulij1ora): II Field trials picloram and di camba ac ids were more treatment s are not reported separately as usin g various herbicides. AII.\·fralilln W<'<'t/s effecti ve than 2.4.5-T ac id (P < 0.0 1). the dibutyl phthalate was found to be 1:3-5. abso lutely without effect. a conclusion Robcrtson. J. A. ( 1965). Chcmical control of En'l//ophil(l lIIilcl/e/lii. Australiall Jour­ Discussion similar to that of Robertson ( 1965) and Beger ( 1969). IIl1l of £,rperillll'llfa/ A~ric ll /l l1 r(' (llId Ani- The results given in Tabl e I are inter­ Similarly. addition of the wetting agent 1//01 Hm·/wI/{lr." 5:299-303 . esting in that they arc consistent with calcium dodecylbell zenesulphonate to the White. C. T. ( 1923) . Weeds of Queensland No. 31. The rubber vine (CI :\,PI(J.~I('x ia data from fi eld trials (Harvey. unpub­ herbicide solutions in diesel disttll ate in xrlllulif/ortl). QII{'{'IIS/WIlI AX riculrural li shed data). except that the much larger Trial 2 was without effect. Joul'l1al 19:286-7. number of plants whic h can be managed The greater phytotoxicit y of picloram in the gla sshouse has all owed the emer­ and di camba over 2.4.5-T shown in gcnce of statisticall y significant differ­ Table 2 was expected. as picioram and ences. whereas the diffe rences in the fi eld dicamba are generally known to be very Acknowledgements resu lt s were not statisticall y signficant. effecti ve arbori cides. The greater effi ­ The only other important d ifference be­ cacy of 2.4.S-T ester over the acid is Mr H . Mulder . D . P. " . Bi o metrics tween fi eld tri als and glasshouse tri als in teresting in that it parallels the re sults Branch. performed the statisti cal anal­ is that in the g lasshouse trials ve ry small o btained with fo liar appl icati o ns o f yses. Messrs P. E. van Ha arcn and L. C. volumes ( 10 microlitres) of concentrated 2.4-0 ester and 2.4-0 acid formulations Orr provided technical assistance.

Tat.le 2 Herbicides used in Trial 2 and results

Chemical Concentration Mortality (%) (% a.e.) Without wetting With wetting agent agent

2.4.5-T 5 96 88 butyl/isoburyl eslers I 42 50 0 .5 t3 t3 O. t a 4 2 .4 .5-T acid 5 83 92 I 8 t7 0.5 4 8 O. 0 0 picloram acid 5 96 96 t 46 7 t 0.5 a t7 O. t 4 13 dicamba acid 5 96 tOO I 54 38 0.5 38 38 0 . 1 0 4