HERBICIDES in Asian rice - IRRI books - International Rice ...

More documents

Recommendations

Info

demand for herbicide combinations capable of controlling annual as well as perennial weeds with one application. Most of these mixtures are based on sulfonyl urea types, such as bensulfuron and pyrazosulfuron. A single application of a herbicide mixture seems to be effective and economical, but relatively early application, within 10 d after transplanting, does not give satisfactory control of E. kuroguwai and Sagittaria triforia, which need a long period for emergence and often escape the residual effect of the herbicides. These species have become the most troublesome weeds in transplanted rice in Korea (Kim 1993a). Changes in weed flora caused by cultural practices About 92 weed species belonging to 27 families are found in Korean ricefields; 30 species are considered to be common weeds (Kim 1981). Changes in weed flora over the last 3 decades may be useful in predicting weed flora changes in other countries as their rice culture changes (Kim 1993a). About 10 species, including both annuals and perennials, were the major weeds in transplanted rice for half a century. The relative importance of different species has been affected by recent changes in rice cultural practices and weed control measures used by farmers, in particular by the type and amount of herbicide applied. The heavy applications of herbicides in rice since 1980 have stabilized weed populations, with perennial weeds dominating. In 1965, before herbicide use had become prevalent, 17 species were identified as common (Table 6). Echinochloa crus-galli was the most troublesome, followed by M. vaginalis, which was also a serious weed in rice seedbeds. Other species were minor weeds. In 1971, Rotala indica was recognized as the dominant species, followed by Eleocharis acicularis, M. vaginalis, C. difformis, E. crus-gulli, Lindernia procurnbens, Potarnogeton distinctus, Aneilema japonica, E. kuroguwai, S. juncoides, and Persicaria hydropiper. These species constituted 86% of all ricefield weeds; 81% are annuals. In 1981, the most important weed was again M. vaginalis, followed by Sagittaria pygrnaea, S. trifolia, P distinctus, Cyperus serotinus, R. indica, A. japonica, L. procumbens, E. kuroguwai, and Ludwigia prostrata. These species constituted 87% of all ricefield weeds; 54% are perennials. In 1990, S. trifolia had become the dominant weed species, followed by S. pygmaea, E. crus-galli, P. distinctus, C. serotinus, and M. vaginalis. About 60% of these species are perennials. Similarity coefficients of change in the level of dominance of different weed species over time were 37-39 from 1971 to 1981, but 62 from 1981 to 1991 (Table 7). This confirms a major change in weed flora between 1971 and 1981, but indicates little change between 1981 and 1991, except that E. kuroguwai and E. crus-galli became the dominant species. Eleocharis kuroguwai and S. trifolia are regarded as the most difficult weeds to control. They require a relatively higher cumulative temperature (417 °C for E. kuroguwai and 297 °C for S. trifolia ) and can easily escape the effects of herbicide applied early, within 5-10 d after transplanting. Ecological forces influencing weed competition and herbicide resistance 137
Table 6. Dominant weed species in Korean ricefields, 1965-90. Weed Dominance of weed a 1965 1971 1981 1990 Life cycle Echinochloa crus-galli Monochoria vaginalis Rotala indica Persicaria hydropiper Ludwigia prostrata Lindernia procumbens Dopatrium junceum Aneilema japonica Cyperus difformis Cyperus iria Sagittaria pygmaea Sagittaria trifolia Potamogeton distinctus Neocharis kuroguwai Cyperus serotinus Neocharis acicularis Scirpus juncoides +++++ +++++ ++ – – – – – – – – – – – – – + ++ +++ +++++ – + + – + ++ – – + + + + ++++ + + ++++ ++ – + – – + – – +++ ++ ++ + ++ – + +++ +++ ++ – + – – + + – +++ +++ ++ +++ ++ – + Annual Annual Annual Annual Annual Annual Annual Annual Annual Annual Perennial Perennial Perennial Perennial Perennial Perennial Perennial a — = present, but of minor importance, + = below 5%, ++ = 5-10%, +++ = 11-20%, ++++ = 21-30%, +++++ = more than 30%. Table 7. Similarity coefficient in terms of changes in dominant species over time (15). Year 1971 1981 1991 1971 (0.208) a 39.3 36.5 1981 (0.111) 62.0 (0.117) a Parentheses indicate index of diversity. Source: Kim (1993a). The currently dominant weed species can be expected to continue as major weeds in Korean ricefields, with varying degrees of dominance, for at least the next 10-20 yr, if current control methods continue to be used. WEED RESISTANCE TO HERBICIDE Herbicide resistance is the inherited ability of a weed io escape control by a herbicide (Gressel 1993). Resistance is relative; one important modifier is the rate of herbicide applied. Resistance to normal agricultural levels of herbicide application is assumed here. Resistance evolves in one of the following ways: 138 Kim
Page 2:
DEDICATION To Keith Moody WEED SCIE
Page 5 and 6:
The International Rice Research Ins
Page 7 and 8:
Bioherbicides and weed management i
Page 9 and 10:
ful insects caused adverse response
Page 11 and 12:
The need to raise yields and mainta
Page 13 and 14:
ACKNOWLEDGMENTS Any volume that dra
Page 16:
Overview
Page 19 and 20:
as more lucrative, full-time job op
Page 21 and 22:
Table 3. Herbicide use in rice prod
Page 23 and 24:
only 3.3:1. The benefit-cost ratio
Page 25 and 26:
EFFECTS ON SOCIETY AND ECOSYSTEMS S
Page 27 and 28:
mulate in soils and in water tables
Page 29 and 30:
unds from the field into canals and
Page 31 and 32:
tion. Even if herbicide mixtures ar
Page 33 and 34:
plant pathogens for controlling gra
Page 35 and 36:
spectrum herbicides glufosinate-amm
Page 37 and 38:
De Datta SK. 1981. Principles and p
Page 39 and 40:
Li KM, Li PZ. 1996. Effect of herbi
Page 41 and 42:
Vongsaroj P. 1994. Weed control in
Page 43 and 44:
i ce env ironments and how they res
Page 45 and 46:
Soil fertility. Monochoria vaginali
Page 47 and 48:
Such problems could be avoided by a
Page 49 and 50:
Ho NK, Md Zuki I. 1988. Weed popula
Page 52 and 53:
HERBICIDES IN UNITED STATES RICE PR
Page 54 and 55:
LOSSES TO WEEDS IN U.S. RICE US. ri
Page 56 and 57:
propanil, which remains the backbon
Page 58 and 59:
4. U.S. rice yields and adoption of
Page 60 and 61:
6. Use of herbicides to control bro
Page 62 and 63:
8. Thiobencarb and molinate transpo
Page 64 and 65:
oping programs that curtail negativ
Page 66 and 67:
Dunshee CF, Jones JW. 1924. Results
Page 68:
Impacts of herbicides
Page 71 and 72:
Pesticide users The pesticide user
Page 73 and 74:
Table 3. Frequency of pesticide app
Page 75 and 76:
Poly- Multiple Eye Pulmonary neurop
Page 77 and 78:
(weight/height) had the expected ne
Page 79 and 80:
Table 5. Anticipated health costs o
Page 81 and 82:
When no consideration is given to h
Page 83 and 84:
MAFF. 1991. Pesticides approved und
Page 85 and 86:
and analyzed. We used this data bas
Page 87 and 88:
soluble herbicide is distributed in
Page 89 and 90:
of the rice herbicides thiobencarb
Page 91 and 92:
germination because they compete fo
Page 93 and 94:
in N 2 fixation and nitrate reducti
Page 95 and 96:
Table 3. Effects of pesticides on n
Page 97 and 98:
transformations in soils are studie
Page 99 and 100:
Floodwater invertebrates Applicatio
Page 101 and 102: tally prevented photosynthetic acti
Page 103 and 104: CITED REFERENCES Almazan LL, Robles
Page 105 and 106: Mandal BB, Bandyopadhyay P, Bandyop
Page 107 and 108: Smith RJ, Flinchum WT, Seaman DE. 1
Page 110 and 111: IMPACT OF HERBICIDE USE ON THE ENVI
Page 112 and 113: Factors that reduce toxic risk Phys
Page 114 and 115: Table 3. Persistence in soil of ric
Page 116 and 117: One infamous herbicide spill occurr
Page 118 and 119: investigated because of the large,
Page 120 and 121: Given the current state of knowledg
Page 122: Way JM, Newman JF, Moore NW, Knaggs
Page 125 and 126: powder)—one-third the total amoun
Page 127 and 128: tants, however—such as cyanide an
Page 129 and 130: In both 1987 and 1988, 42 t of copp
Page 131 and 132: compounds such as the germicide Aso
Page 133 and 134: otation of one wet season, one dry
Page 136 and 137: ECOLOGICAL FORCES INFLUENCING CROP-
Page 138 and 139: may also vary with the resource use
Page 140 and 141: crease competitive ability into cro
Page 142: Tilman D. 1988. Plant strategies an
Page 145 and 146: Table 1. Important rice weeds in te
Page 147 and 148: 2. Costs of production of rice and
Page 149 and 150: covered only about 7,500 ha in 1993
Page 151: Table 5. Herbicide-treated area in
Page 155 and 156: cides in the mix. Most mixtures, wh
Page 157 and 158: Kim KU, Shin DH. 1993. Development
Page 160 and 161: INTEGRATED WEED MANAGEMENT IN RICE
Page 162 and 163: after crop establishment) mostly co
Page 164 and 165: Table 2. Most common rice herbicide
Page 166 and 167: Table 4. Examples of rice herbicide
Page 168 and 169: portant where direct method options
Page 170 and 171: too wet. Optimum moisture is needed
Page 172 and 173: For direct-seeded rice, the availab
Page 174 and 175: visible effects. These methods are
Page 176 and 177: CITED REFERENCES Ampong-Nyarko K, D
Page 178 and 179: Jikihara K, Kimura I. 1977. Benthio
Page 180: Watson AK. 1992. Current status of
Page 183 and 184: 1. Framework for planning and imple
Page 185 and 186: Baseline data The problems associat
Page 187: 3. Filling vacant areas in the fiel
Page 190 and 191: emained the dominant weed, their in
Page 192 and 193: 6. Cultural practices in the Muda a
Page 194 and 195: LESSONS LEARNED FROM THE PROGRAM St
Page 196: Ho NK, Md Zuki I, Asna BO. 1990. Th
Page 199 and 200: Using mycoherbicides involves apply
Page 201 and 202: Community education also is importa
Page 203 and 204:
the crop of interest. This should i
Page 205 and 206:
asically biological, technological,
Page 207 and 208:
cause they are likely to be applied
Page 209 and 210:
Similarly, the risks of bioherbicid
Page 211 and 212:
Baki MM, Azmi M. 1992. Integrated m
Page 213 and 214:
Matthews GA, Bateman RP. 1990. Appl
Page 215 and 216:
Watson AK. 1985. Host specificity o
Page 217 and 218:
vars as it was with very short-dura
Page 219 and 220:
While it may not be possible to ide
Page 221 and 222:
CITED REFERENCES Ahmad S, Majid A,
Page 224 and 225:
USING BIOTECHNOLOGY IN GENETIC IMPR
Page 226 and 227:
Molecular markers are being used ro
Page 228 and 229:
use of herbicides as part of a rice
Page 230 and 231:
A final strategy would be to use bi
Page 232:
Rathore KS, Chowdhury VK, Hodges TK
Page 235 and 236:
Putnam and Duke (1974) postulated t
Page 237 and 238:
Visual ratings were made 7 wk after
Page 239 and 240:
nels; and most of the genotypes tha
Page 241 and 242:
Leaf Root Leaf Root Leaf Root Leaf
Page 243 and 244:
One hypothesis is that rice plants
Page 246:
Use of herbicides in Asian rice
Page 249 and 250:
icides such as 2,4-D and butachlor
Page 251 and 252:
lems, it has resulted in quantitati
Page 253 and 254:
Reasons for herbicide selection Far
Page 255 and 256:
Carey VP III, Talbert RE, Baltazar
Page 258 and 259:
EXPERIENCE WITH RICE HERBICIDES IN
Page 260 and 261:
2. Time spent weeding Japanese rice
Page 262 and 263:
3. Area of Japanese ricefields rece
Page 264 and 265:
4. Sequence of herbicide applicatio
Page 266 and 267:
Table 6. Important weed species in
Page 268 and 269:
CURRENT PROBLEMS IN WEED MANAGEMENT
Page 270 and 271:
DEVELOPING A WEED MANAGEMENT STRATE
Page 272 and 273:
(Timmer et al 1983, World Bank 1993
Page 274 and 275:
gets of plant growth regulators and
Page 276 and 277:
in their role of implementing agric
Page 278 and 279:
clearly needed if farmers are to av
Page 280 and 281:
Kuhrt WJ. 1992. The California grap
Page 282 and 283:
Participants Dr. Heidi Albers Food
Page 284 and 285:
Dr. Gurdev S. Khush International R
show all

HERBICIDES in Asian rice - IRRI books - International Rice ...

Create successful ePaper yourself

Delete template?

Save as template?