WILD OAT INTERFERENCE IN SUNFLOWER

1985 ◽  
Vol 65 (1) ◽  
pp. 219-222 ◽  
Author(s):  
W. O. CHUBB ◽  
G. H. FRIESEN

In field experiments, sunflower (Helianthus annuus L. ’Hybrid 894’) recovered from initial effects of wild oat (Avena fatua L.) interference and yielded normally if the weed was removed within 4 wk after crop emergence and the crop was kept relatively free of wild oats thereafter until harvest. In widely spaced plantings, wild oats growing between-the-rows competed just as vigorously as in-the-row infestations. Selective postemergence herbicides did not always provide sufficient control of wild oats to prevent significant losses in sunflower yield.Key words: Competition, interference, seed yield, oil content, herbicides, critical period

Weed Science ◽  
1983 ◽  
Vol 31 (6) ◽  
pp. 889-891 ◽  
Author(s):  
P. Ashley O'Sullivan

Field experiments were conducted for 2 yr to determine the influence of picloram (4-amino-3,5,6-trichloropicolinic acid) and a commercial mixture of picloram plus 2,4-D [(2,4-dichlorophenoxy)acetic acid] (1:16, w/w) on control of wild oats (Avena fatua L. # AVEFA) with four postemergence herbicides. The phytotoxicity to wild oats of barban (4-chloro-2-butynyl m-chlorocarbanilate) or difenzoquat (1,2-dimethyl-3,5-diphenyl-1H-pyrazolium) in 1981 and diclofop {2-[4-(2,4-dichlorophenoxy)-phenoxy] propanoic acid} or flamprop [N-benzoyl-N-(3-chloro-4-fluorophenyl)-DL-alanine] in 1981 and 1982 was reduced when these herbicides were applied in a mixture with picloram plus 2,4-D. Consequently, the use of these mixtures for broad-spectrum weed control in one spray operation is not recommended. Picloram applied at a rate equivalent to the amount present in the picloram plus 2,4-D mixture did not influence the control of wild oats obtained with any herbicide, indicating that the antagonism was due to the 2,4-D component of the picloram plus 2,4-D mixture.


1997 ◽  
Vol 11 (2) ◽  
pp. 283-289 ◽  
Author(s):  
Robert N. Stougaard ◽  
Bruce D. Maxwell ◽  
Jerry D. Harris

Field experiments were conducted during 1992 and 1993 at Kalispell and Moccasin, MT, to determine the influence of application timing on the efficacy of reduced rate postemergence applications of imazamethabenz and diclofop in spring barley. Herbicides were applied at their respective 1 × and ½ × use rates at either 1, 2, or 3 weeks after crop emergence (WAE). While excellent wild oat control was sometimes achieved with reduced rates, there was no consistent relationship between wild oat growth stage and the level of control at either site regardless of the herbicide or rate applied. This response suggests that efficacy is governed not only by wild oat growth stage, but also by weed demographics and environmental considerations. Barley yield and adjusted gross return values were highest at Kalispell when imazamethabenz treatments were applied at 1 WAE, regardless of the level of wild oat control. Adjusted gross return values were similar for the 1 × and ½ × imazamethabenz treatments. Yields and adjusted gross returns with diclofop treatments were more related to the level of wild oat control at Kalispell, with the 1 × diclofop treatments providing the greatest yields and adjusted gross return values. The level of wild oat control at Moccasin had minimal effect on barley yield and adjusted gross returns, with both values being comparable to the nontreated check.


1983 ◽  
Vol 63 (2) ◽  
pp. 503-507 ◽  
Author(s):  
M. P. SHARMA ◽  
W. H. VANDEN BORN

Field experiments were conducted over a 2-yr period to evaluate the need for competition by crop plants along with the application of postemergence herbicides for wild oat (Avena fatua L.) control in barley and wheat. Barban, difenzoquat, and barban plus difenzoquat were used in barley and barban, benzoylprop ethyl, diclofop methyl, flamprop methyl, and barban plus benzoylprop ethyl were used in wheat, at the two-leaf stage and the four-leaf stage of wild oats seeded alone or in a crop. Barban and diclofop methyl were effective for wild oat control at both the two-leaf and four-leaf stage of wild oats. Benzoylprop ethyl, difenzoquat and flamprop methyl alone or in combination with barban were more effective at the four-leaf than at the two-leaf stage of wild oats. Herbicide treatments increased barley yield up to 84% and wheat yield up to 177%. In the absence of herbicide treatments, crop competition from barley or wheat reduced the wild oat dry weight by about 50%. Competition by crop plants was essential for effective wild oat control with all foliage-applied wild oat herbicides included in this study.Key words: Competition, crop, wild oat, herbicides, wheat, barley


2017 ◽  
Vol 8 (1) ◽  
pp. 96
Author(s):  
A.U. Ingle ◽  
S.S. Nichal ◽  
V.L. Gawande ◽  
E.R. Vaidya ◽  
B.S. Kharat

Helia ◽  
2001 ◽  
Vol 24 (34) ◽  
pp. 115-120
Author(s):  
G. Nanjundappa ◽  
B. Shivaraj ◽  
S. Janarjuna ◽  
S. Sridhara

SUMMARY Field experiments have been conducted to study the effect of organic and inorganic sources of nutrients applied alone or in combination on the growth and yield of sunflower. Application of a recommended dose of fertilizer (62.5:75:62.5 kg NPK ha-1) coupled with 10 t ha-1 of farmyard manure has recorded highest seed and stalk yields of sunflower. Growth and yield parameters were also favorably influenced by the application of the recommended dose of fertilizer coupled with farmyard manure. Seed oil content was not influenced by the application of organic or inorganic sources of nutrients.


1989 ◽  
Vol 69 (4) ◽  
pp. 1251-1254 ◽  
Author(s):  
G. H. GUBBELS ◽  
W. DEDIO

Field experiments were conducted in 1983, 1984 and 1986 to determine the response of Sun M 20 (early) and 894 (late) sunflower (Helianthus annuus L.) hybrids to three plant densities (30 000, 45 000 and 60 000 plants ha−1) at two seeding dates (18–24 May and 13–16 June). With increase in plant density, achene yields followed the same trends in each seeding date for both hybrids. Yields were similar at the 30 000 and 45 000 plant densities, but lower at the 60 000 density. Plant height and oil content of achenes increased while achene weight decreased with increase in plant density. Plant height was greater but achene weight, oil content and achene yield were lower in the late than the early seeding.Key words: Sunflower, Helianthus annuus L., plant density, seeding date


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