Biocontrol efficacy of Colletotrichum truncatum for hemp sesbania (Sesbania exaltata) is enhanced with unrefined corn oil and surfactant

2007 ◽  
Vol 7 (1) ◽  
pp. 70-76 ◽  
Author(s):  
C. DOUGLAS BOYETTE ◽  
ROBERT E. HOAGLAND ◽  
MARK A. WEAVER
Keyword(s):  
Corn Oil ◽  
Colletotrichum Truncatum ◽  
Biocontrol Efficacy ◽  
Sesbania Exaltata ◽  
Hemp Sesbania

Unrefined Corn Oil Improves the Mycoherbicidal Activity ofColletotrichum truncatumfor Hemp Sesbania (Sesbania exaltata) Control

1994 ◽  
Vol 8 (3) ◽  
pp. 526-529 ◽  
Author(s):  
C. Douglas Boyette
Keyword(s):  
Corn Oil ◽  
Colletotrichum Truncatum ◽  
Greenhouse Experiments ◽  
Sesbania Exaltata ◽  
Oil Tank ◽  
Spray Volume ◽  
Hemp Sesbania

In greenhouse experiments, unrefined corn oil was tested as an adjuvant with the mycoherbicidal fungus,Colletotrichum truncatum.A1:1 (V/V) fungus/corn oil tank mixture extended by at least 70 h the period of time in which the fungus remains infective between inoculation and the onset of dew. This formulation also reduced the dew period requirements for optimal weed pathogenesis and mortality from 12 h to 2 h, and reduced the required spray volume by 100-fold, from 500 L/ha to 5 L/ha. These results suggest that formulatingC. truncatumin unrefined corn oil greatly improves the bioherbicidal potential of this pathogen.

Biological Control of Hemp sesbania (Sesbania exaltata) and Sicklepod (Senna obtusifolia) in Soybean with Anthracnose Pathogen Mixtures

2010 ◽  
Vol 24 (4) ◽  
pp. 551-556 ◽  
Author(s):  
C. Douglas Boyette ◽  
Robert E. Hoagland
Keyword(s):  
Weight Reduction ◽  
Field Experiments ◽  
Corn Oil ◽  
Dry Weight ◽  
Single Application ◽  
Sesbania Exaltata ◽  
Simultaneous Control ◽  
Weed Hosts ◽  
Hemp Sesbania ◽  
Narrow Row

In greenhouse and field experiments conducted over 3 yr, tank mixtures of spores of the fungiColletotrichum truncatumandColletotrichum gloeosporioides, formulated in unrefined corn oil and Silwet L-77 surfactant, were evaluated as a mycoherbicide mixture for simultaneous control of hemp sesbania and sicklepod, respectively. In greenhouse tests, 100% mortality and dry weight reduction of hemp sesbania occurred 6 d after treatment (DAT), whereas 15 d were required to achieve 100% mortality and dry weight reduction of sicklepod. In field experiments conducted in narrow-row (51-cm) soybean test plots, a single application of the fungal mixture formulated as described controlled hemp sesbania and sicklepod 94% and 88%, respectively, 28 DAT. Neither fungus, applied as aqueous conidial suspensions, provided control of their respective weed hosts. These results indicate that tank mixtures of these anthracnose-forming pathogens can effectively control hemp sesbania and sicklepod with a single application.

Biological Control of Hemp Sesbania (Sesbania exaltata) Under Field Conditions withColletotrichum truncatumFormulated in an Invert Emulsion

Weed Science ◽  
1993 ◽  
Vol 41 (3) ◽  
pp. 497-500 ◽  
Author(s):  
C. Douglas Boyette ◽  
Paul C. Quimby ◽  
Charles T. Bryson ◽  
Grant H. Egley ◽  
Floyd E. Fulgham
Keyword(s):  
Biological Control ◽  
Weed Control ◽  
Field Experiments ◽  
Field Conditions ◽  
Colletotrichum Truncatum ◽  
Greenhouse Experiments ◽  
Sesbania Exaltata ◽  
Invert Emulsion ◽  
Emulsion Formulation ◽  
Hemp Sesbania

In greenhouse experiments, conidia ofColletotrichum truncatumapplied in an invert emulsion formulation controlled hemp sesbania 100% in the absence of a dew treatment. In field experiments, hemp sesbania control averaged 95 and 97% in 1989 and 1990, respectively, when this formulation was applied to hemp sesbania seedlings using tractor-mounted, air-assist nozzles. This level of weed control was comparable to that achieved from the herbicide acifluorfen. These results indicate thatC. truncatumhas excellent potential as a mycoherbicide for controlling hemp sesbania and that this potential can be augmented by formulating the pathogen as an invert emulsion.

Interference between hemp sesbania (Sesbania exaltata) and soybean (Glycine max) in response to irrigation and nitrogen

Weed Science ◽  
1997 ◽  
Vol 45 (1) ◽  
pp. 91-97 ◽  
Author(s):  
C. Andy King ◽  
Larry C. Purcell
Keyword(s):  
Field Experiments ◽  
Yield Loss ◽  
Individual Species ◽  
Weed Species ◽  
Soybean Yield ◽  
Sesbania Exaltata ◽  
Competition For Light ◽  
Hemp Sesbania ◽  
Chamber Studies ◽  
Growth Chamber Studies

Soybean yield loss from weed interference depends upon weed density and competitiveness of crop and weed species in response to environment. Soil water availability and nitrogen fertility were evaluated for their effect on competitiveness of individual species in field experiments. Early-season temperatures in 1995, which were cool compared to 1994, slowed hemp sesbania growth without affecting soybean growth. This resulted in negligible competition with soybean by hemp sesbania at densities of 3 or 6 plants m−2. In 1994, hemp sesbania grew above the soybean canopy, decreasing soybean light interception 29 to 68%, and reducing soybean yield 30 to 48%. Fertilizer nitrogen increased soybean competitiveness, as indicated by biomass production, only in irrigated plots with hemp sesbania at 3 m−2, but did not affect soybean yield. Apparently, competition for light is a primary cause of soybean yield loss from hemp sesbania infestations. In growth chamber studies, simulating temperatures from the field, hemp sesbania growth was stimulated more by warm temperatures than was soybean. Hemp sesbania and soybean dry weights increased 4.4- and 2.7-fold, respectively, at 30/20 C day/night temperatures compared to 25/15 C.

Effects of Johnsongrass (Sorghum halepense), Hemp Sesbania (Sesbania exaltata), and Delayed Harvest on Soybeans

1993 ◽  
Vol 7 (2) ◽  
pp. 355-360 ◽  
Author(s):  
Chester G. McWhorter ◽  
James M. Anderson
Keyword(s):  
Harvest Date ◽  
Sorghum Halepense ◽  
Foreign Material ◽  
Soybean Cultivars ◽  
Sesbania Exaltata ◽  
Harvest Dates ◽  
Early Maturing ◽  
Hemp Sesbania

The effect of delayed harvest was investigated with two soybean cultivars that were grown weed free or in competition with johnsongrass or hemp sesbania over a 3-yr period. Johnsongrass reduced the yield of early-maturing ‘Hill’ soybean 32, 35, and 36% when harvested at an average of 1, 2, or 3 wk after maturity, when compared to weed-free yields of 2490, 2430, and 2270 kg ha−1, respectively. Late-maturing ‘Lee 68’ yields were reduced 27, 29, and 39% on three harvest dates compared to weed-free yields of 2570, 2310, and 2200 kg ha−1, respectively. Seed grades of both cultivars improved with delayed harvest, but this was offset when johnsongrass was present. Hemp sesbania reduced yields of Hill 23% on the first harvest date and 26% on the second and third dates. Yields of Lee 68 were reduced 16, 22, and 28% by hemp sesbania on three successive harvest dates. The value of soybean yields adjusted for excessive foreign material, moisture, and damaged kernels was decreased by delayed harvest when hemp sesbania was present in Lee 68 and when johnsongrass was present in both cultivars.

Weed Competition in Rice

Weed Science ◽  
1968 ◽  
Vol 16 (2) ◽  
pp. 252-255 ◽  
Author(s):  
Roy J. Smith
Keyword(s):  
Oryza Sativa ◽  
Weed Competition ◽  
Early Season ◽  
Echinochloa Crusgalli ◽  
Late Season ◽  
Sesbania Exaltata ◽  
Hemp Sesbania

Barnyardgrass [Echinochloa crusgalli (L.) Beauv.], duck-salad [Heteranthera limosa (Sw.) Willd.], hemp sesbania [Sesbania exaltata (Raf.) Cory], and northern jointvetch [Aeschynomene virginica (L.) B.S.P.] significantly reduced rice [Oryza sativa L.] yields. Damage to rice increased as populations of barnyardgrass, hemp sesbania, and northern jointvetch increased. Barnyardgrass and duck-salad lowered yields during early season, but hemp sesbania and northern jointvetch decreased yields in late season.

Moisture Stress and Hydration-Dehydration Effects on Hemp Sesbania (Sesbania exaltata) Seed Germination

Weed Science ◽  
1980 ◽  
Vol 28 (5) ◽  
pp. 487-492 ◽  
Author(s):  
Robert D. Williams
Keyword(s):  
Seed Germination ◽  
Osmotic Potential ◽  
Moisture Stress ◽  
Germination Percentage ◽  
Moisture Uptake ◽  
Sesbania Exaltata ◽  
Hemp Sesbania ◽  
Number Of Cycles

Increased osmotic potential from 0 to −14 bars decreased the moisture uptake and germination of mechanically scarified hemp sesbania [Sesbania exaltata(Raf.) Cory] seed. Germination percentage for osmotic potential of 0, −2, −4, −6, and −8 bars was 86%, 86%, 70%, 19%, and 1%, respectively. This response to moisture stress was modified by imbibition, or hydration-dehydration, of the seed prior to the moisture stress. Imbibing the seed for as little as 2 h significantly increased its subsequent germination against moisture stress. One hydration-dehydration cycle had little or no effect on germination, but as the number of cycles increased, the germination percentage decreased. Prolonged hydration of 3 and 7 days followed by dehydration greatly reduced subsequent seed germination.

Interference and Critical Time of Removal of Hemp Sesbania (Sesbania exaltata) in Cotton (Gossypium hirsutum)

1990 ◽  
Vol 4 (4) ◽  
pp. 833-837 ◽  
Author(s):  
Charles T. Bryson
Keyword(s):  
Gossypium Hirsutum ◽  
Field Experiment ◽  
Weed Control ◽  
Critical Period ◽  
Critical Time ◽  
Seedling Vigor ◽  
Seed Cotton ◽  
Sesbania Exaltata ◽  
White Cotton ◽  
Hemp Sesbania

Hemp sesbania interference in cotton was investigated in the greenhouse and in a 2-yr field experiment at Stoneville, MS. In greenhouse experiments, cotton and hemp sesbania heights and plant dry weights (PDW) were not different in ratios of cotton to hemp sesbania of 4:0, 2:2, 1:3, and 0:4 at 3 and 5 wk after emergence (WAE). Hemp sesbania PDW were less for ratios of cotton to hemp sesbania of 3:1 when compared to hemp sesbania PDW of other ratios. Early season cotton seedling vigor and growth (0 to 28 DAP) were not affected by 32 000 hemp sesbania plants ha-1(3 plants m of row-1). Hemp sesbania plants were hand removed 28, 42, 56, 70, and 84 d after planting (DAP). White cotton blooms and yields were reduced when hemp sesbania plants were not removed by 70 DAP. Seed cotton yields were 2590, 2570, 2460, 2030, 1610, and 1070 kg ha-1for hemp sesbania removed at 28, 42, 46, 70 and 84 DAP or not removed, respectively. The critical period of weed control or removal of hemp sesbania in cotton is ≤62 DAP.

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