IAEA-TECDOC Use of isotopic tracers in studies of herbicide performance

Transcription

1 IAEA-TECDOC-1003 Use of isotopic tracers in studies of herbicide performance on grasses

2

3 The originating Section of this publication in the IAEA was: Food

4 FOREWORD Herbicide products as sold to the user are a mixture or formulation of active ingredient, surfactants and other adjuvants, plus a carrier, which will be a liquid if the formulation is to be applied as a spray. The adjuvants affect the characteristics of the spray, including the retention of the droplets by plant surfaces and the penetration of active ingredient into the plant. Thus they play

5 EDITORIAL NOTE In preparing this publication for press, staff of the IAEA have made up the pages from the original manuscripts as submitted by the authors. The views expressed do not necessarily reflect those of the IAEA, the governments of the nominating Member States or the nominating organizations. Throughout the text names of Member States are retained as they were when the text was compiled. The

6 SUMMARY CONTENTS

7 SUMMARY OF THE CO-ORDINATED RESEARCH PROGRAMME 1. INTRODUCTION Herbicides, like

8 Cynodon dactylon (purple nutsedge) was chosen for study in this programme because it has been classified as the "world's worst weed"; it occurs in 92 countries and is a serious weed in over 50 crops [2]. It spreads by rhizomes which also produce tubers that continue to proliferate forming chains that

9 promising components

10 in some cases cheap local household detergents, such as washing-up liquids, were included among

11 results. This is supported by the report from Malaysia that 100 L ha was more effective than 400 L. These possibilities are,

12 [5] TURNER, D.J., "Effects on glyphosate performance of formulation additives and mixing with other herbicides", The Herbicide Glyphosate (GROSSBARD, E. ATKINSON, D., Eds), Butterworths (1984) 221. [6] TERRY, P.J., "Efficacy of glyphosate for weed control in the tropics", The Herbicide Glyphosate (GROSSBARD,

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14 TABLE 1. THE UPTAKE OF PERMETHRIN AND ETHIRIMOL INTO ORANGE LEAVES Surfactant Percentage uptake Arquad

15 TABLE 3. THE UPTAKE OF ETfflRIMOL INTO ORANGE LEAVES AT TWO CONCENTRATIONS

16 about 1000 mg/l in a 5% surfactant solution. Transient concentrations of surfactant of 5% or more occur when spray drops dry, with final equilibrium concentrations

17 other. A number of emulsions have been tested, and found to give improved uptake but there is no way to confirm that this is the result of emulsification of the cuticle waxes or some other aspect of the uptake process, such as emulsification of the pesticide, reducing precipitation, or maintaining

18 solution would allow the spray drops to flow directly into the open stomata, but there is some evidence that the actual process is more complex than this.

19 STUDIES OF HERBICIDE PERFORMANCE IN GRASSES AND SEDGES C.L. FUENTES,

20 TABLE

21 C. rotundas control was assessed in cropped plots 30, 60 and 90 days after treatment (DAT) using a visual scale (0 = no control; 100 = total control). Also, density (tillers m 2 ) was recorded

22 TABLE

23 TABLE C-GLYPHOSATE UPTAKE

24 00 TABLE

25 3.2. Field experiment Tiller density The density of C. rotundus was homogeneous in the experimental area before the glyphosate was applied. This was verified when significant differences on the density were not detected among the plots (Table 5). TABLE 5. CYPERUS ROTUNDUS DENSITY (SHOOTS nt) IN CROPPED PLOTS Treatment Days after treatment %of increasing 1. Untreated 2. Mechanical control a a a bed a b a b

26 glyphosate was to reduce the purple nutsedge population or at least keep them stable during the period of the experiment. The glyphosate treatments at the high rate (1.5 kg ha" 1 ) produced the greatest decrease of the C. rotundus population, e.g. 30% to 40%, when the herbicide

27 TABLE 7. CYPERUS ROTUNDUS DRY WEIGHT (gnt 2 ) IN CROPPED PLOTS Treatment 1. Untreated 2. Mechanical control Glyphosate application at 9 a.m. 3. Glyphosate 1.5 kg a.e. ha" 1 unamended 4. Glyphosate 1.5 kg a.e. ha" 1 amended 5. Glyphosate 0.75 kg a.e, ha~' amended Days after treatment

28 INFLUENCE OF PALM OIL ON THE EFFICACY OF GLYPHOSATE IN THE CONTROL OF CYPERUS ROTUNDUS L XA ROSLIB. MOHAMAD, DZOLKHDFLI OMAR Faculty of Agriculture, Universiti Pertanian Malaysia, Serdang, Selangor, Malaysia Abstract The influence of the addition of palm oil to the formulation on the efficacy of glyphosate for the control of Cyperus rotundus was evaluated in the laboratory, glass-house and field. Triton X-100 failed to maintain a stable emulsion of palm oil in the formulation 10 minutes after mixing. In glass-house experiments adding mineral

29 within ±20%

30 TABLE 2. SPRAY FORMULATIONS Treatment Tl Formulation Control

31 TABLE

32 Tubers taken from the treated plants at 2 weeks after the treatments were subjected to standard tetrazolium chloride test

33 TABLE

34 Affect of spray volume application rates

35 Chlorophyll content of the treated plants also showed variations on the 3rd day. However, the results seem to stabilize on day 6 and further on to day 10 (Table 10). Evaluation of the chlorophyll content showed that there

36 4. CONCLUSIONS Triton X-100 could

37 STUDIES ON THE PERFORMANCE OF GLYPHOSATE IN THE CONTROL XA

38 major role

39 (D) Roundup

40 both cropped

41 Tween-80 with diesel oil as an adjuvant in the absence of ammonium sulfate resulted in 96.2% absorption, whereas with ammonium sulfate there was only 66.2% absorption (Table

42

43 Tween-20 with coconut

44 There

45 Weed control as measured by dry weight of weeds was effective with 1.5 kg a.e. ha ' of amended "Roundup" applied in the evening and it was equivalent to all the other treatments except 0.5 kg a.e. ha" 1 amended "Roundup" applied in the morning and unweeded control Maize yield Fresh weight of cobs (four) recorded was highest (377.5g) with unamended Roundup applied at the rate of 1.5 kg a.e. ha"

46 In

47 [20] SUWUNNAMEK,

48 EFFECT

49 midrib

50 There

51 USE OF ISOTOPIC TRACERS IN STUDIES ON 14 C-GLYPHOSATE PERFORMANCE ON CYPERUS ROTUNDUS XA

52 2. MATERIALS AND METHODS 2.1.Laboratory experiments Estimation

53 Modification of treatment studies The best treatment from experiment 2 was selected and formulation No. F was modified by replacing 1% diesel oil with 0.5% or 2% diesel oil or with 1% glycerol Short term penetration studies Formulations D and F were selected for the above experiment and penetration was measured over 1 hour and 2 hours following the revised protocol Field experiments Layout

54

55 TABLE

56 The assessment of weed population in the field plots made two days before herbicide application showed that the population was uniform over the whole site (Tables 4 and 5).

57 TABLE 8. DRY WEIGHT OF CYPERUS PLANTS IN PLOTS TREATED WITH DIFFERENT CONCENTRATIONS AND FORMULATIONS OF GLYPHOSATE Treatment Morning plots Evening plots Average weight Weight loss After 4 week After 8 week after 4 week After 8 week Control a 71.6 a 1.5 kg/ha unamended "Roundup" c 68.6 b 1.5 kg/ha amended "Roundup" Id 71.5 a 0.75 kg/ha amended "Roundup" c 68.7 b 0.5 kg/ha amended "Roundup" b 72.0 a The values

58 The fresh weight data of the plants in the uncropped pots (Table?) show that 1.5 kg/ha amended and unamended "Roundup" and 0.75 kg/ha amended "Roundup" significantly reduced fresh weight

59 [9] HOLT, H.A., SHERRICK, S.L., HESS F.D., Effect of adjuvants and environment during plant development on glyphosate absorption and translocation in field bind weed, Weed Res.

60 EFFECT

61 spray adjuvants and the manipulation of spraying time. The environment was also modified in some cases

62 under

63 Data

64 infested with both the natural weed flora and C. rotundus yielded, significantly, shorter plants. "Roundup"

65 EFFECTS OF ADDITIVES ON GLYPHOSATE ACTIVITY IN PURPLE NUTSEDGE ^ RUNGSIT SUWANKETNIKOM Department of Agronomy, Kasetsart University, Bangkok, Thailand Abstract 14 Effects of additives on C-glyphosate penetration into purple nutsedge leaves were examined in the laboratory. and efficacy of glyphosate for purple nutsedge control was studied in the greenhouse and field The addition of

66 weeks after planting). Eight drops 14

67 a T-jet, flat fan No The pressure was 87 kg/cm^. The temperature before 9.0 a.m. was 27 C with

68 14 (Table 2). (NH 4 ) 2 SO 4 + Triton X oil increased C-glyphosate penetration into nutsedge leaves

69 At 14 days after application, (NH 4 ) 2 SO 4 at 1.0% + oil at 1.0% + Tendal at 0.12 or 0.25 or 1.0% increased the activity of glyphosate at 0.5 and 0.75 kg a.e./ha However, at 21 days after application, the additives increased activity of glyphosate only at 0.5 kg a.e./ha (Table 4). TABLE 4. PURPLE NUTSEDGE CONTROL WITH GLYPHOSATE IN COMBINATION WITH VARIOUS ADDITIVES UNDER GREENHOUSE CONDITIONS Glyphosate (NH 4 ).,SO 4 (kg a.e./ha) (% v/v) Nontreated - Diesel oil Tendal

70 TABLE

71 TABLE

72 TABLE 11. EFFECT OF GLYPHOSATE IN COMBINATION WITH VARIOUS ADDITIVES ON DRY WEIGHT AND NUMBER OF PURPLE NUTSEDGE PLANTS IN CORN AREA AT HARVESTING Glyphosate (kg a e /ha) 1

73 REFERENCES [1] HOLM, L.G., PLUCKNETT, D.L., PANCHO, J.V., HERBERGER J.P., The World Worst Weeds.

74 Appendix EXPERIMENTAL PROTOCOLS 1. FIRST PHASE 1.1. Leaf penetration study

75 Therefore,

76 2. SECOND PHASE 2.1. Introduction

77 B. "Roundup" + ammonium sulfate: As for A above but replace 25 ul of the water with 25uL4%(NH4) 2 SO 4. f i C. "Roundup" + Triton X-100: As for A with addition of the amount of Triton X-100 determined in 1) above. D. "Roundup"

78 necessary. The uncropped plots will be 3 x 2 m and the cropped plots 5 x 5 m. Layout should

79 LIST OF PARTICIPANTS Babiker, Abdel G.T. Gezira Research Station, Botany & Plant Pathology Section, Agricultural Research Corporation, P.O. Barredo-Medina, M.J. Fuentes, C.L. Hance, R.J. Rosli Mohamad Price, C.E. Mallikarjuna Swamy Putchala Qureshi, Jamil M. Suwanketnikom, Rungsit Wills, G.D.