Soil bacteria as selective biological control agents of winter annual grass weeds in winter wheat

AbstractDowny brome, feral rye, and jointed goatgrass are problematic winter annual grasses in central Great Plains winter wheat production. Integrated control strategies are needed to manage winter annual grasses and reduce selection pressure exerted on these weed populations by the limited herbicide options currently available. Harvest weed-seed control (HWSC) methods aim to remove or destroy weed seeds, thereby reducing seed-bank enrichment at crop harvest. An added advantage is the potential to reduce herbicide-resistant weed seeds that are more likely to be present at harvest, thereby providing a nonchemical resistance-management strategy. Our objective was to assess the potential for HWSC of winter annual grass weeds in winter wheat by measuring seed retention at harvest and destruction percentage in an impact mill. During 2015 and 2016, 40 wheat fields in eastern Colorado were sampled. Seed retention was quantified and compared per weed species by counting seed retained above the harvested fraction of the wheat upper canopy (15 cm and above), seed retained below 15 cm, and shattered seed on the soil surface at wheat harvest. A stand-mounted impact mill device was used to determine the percent seed destruction of grass weed species in processed wheat chaff. Averaged across both years, seed retention (±SE) was 75% ± 2.9%, 90% ± 1.7%, and 76% ± 4.3% for downy brome, feral rye, and jointed goatgrass, respectively. Seed retention was most variable for downy brome, because 59% of the samples had at least 75% seed retention, whereas the proportions for feral rye and jointed goatgrass samples with at least 75% seed retention were 93% and 70%, respectively. Weed seed destruction percentages were at least 98% for all three species. These results suggest HWSC could be implemented as an integrated strategy for winter annual grass management in central Great Plains winter wheat cropping systems.

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Imazamox for Winter Annual Grass Control in Imidazolinone-Tolerant Winter Wheat

Weed Technology ◽

10.1614/wt-03-115r1 ◽

2004 ◽

Vol 18 (4) ◽

pp. 924-930 ◽

Cited By ~ 20

Author(s):

Patrick W. Geier ◽

Phillip W. Stahlman ◽

Anthony D. White ◽

Stephen D. Miller ◽

Craig M. Alford ◽

...

Keyword(s):

Winter Wheat ◽

Field Experiments ◽

Wheat Yield ◽

Early Spring ◽

Annual Grass ◽

Application Timing ◽

Jointed Goatgrass ◽

Early Fall ◽

Winter Annual ◽

Feral Rye

Field experiments were conducted at five locations in Kansas, Nebraska, and Wyoming to determine the effects of imazamox rate and application timing on winter annual grass control and crop response in imidazolinone-tolerant winter wheat. Imazamox at 35, 44, or 53 g ai/ha applied early-fall postemergence (EFP), late-fall postemergence, early-spring postemergence (ESP), or late-spring postemergence (LSP) controlled jointed goatgrass at least 95% in all experiments. Feral rye control with imazamox was 95 to 99%, regardless of rate or application timing at Hays, KS, in 2001. Feral rye control at Sidney, NE, and Torrington, WY, was highest (78 to 85%) with imazamox at 44 or 53 g/ha. At Sidney and Torrington, feral rye control was greatest when imazamox was applied EFP. Imazamox stunted wheat <10% in two experiments at Torrington, but EFP or LSP herbicide treatments in the Sidney experiment and ESP or LSP treatments in two Hays experiments caused moderate (12 to 34%) wheat injury. Wheat injury increased as imazamox rate increased. Wheat receiving imazamox LSP yielded less grain than wheat treated at other application timings in each Hays experiment and at Sidney in 2001. No yield differences occurred in one Torrington experiment. However, yields generally decreased as imazamox application timing was delayed in the other Torrington experiment. Generally, imazamox applied in the fall provided the greatest weed control, caused the least wheat injury, and maximized wheat yield.

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Dose-Responses of Weeds and Winter Wheat (Triticum aestivum) to MON 37500

Weed Technology ◽

10.1017/s0890037x0004094x ◽

1996 ◽

Vol 10 (4) ◽

pp. 870-875 ◽

Cited By ~ 12

Author(s):

Patrick W. Geier ◽

Phillip W. Stahlman

Keyword(s):

Winter Wheat ◽

Residual Effects ◽

Downy Brome ◽

Annual Grass ◽

Jointed Goatgrass ◽

Weed Growth ◽

Annual Grasses ◽

Winter Annual ◽

Dose Responses ◽

Weed Emergence

Greenhouse studies determined the dose-responses of cheat, downy brome, Japanese brome, jointed goatgrass, and winter wheat to preplant-incorporated MON 37500 and its residual effects on kochia. Concentrations of MON 37500 up to 60 ppbw did not affect winter wheat. MON 37500 did not prevent weed emergence, but increasingly inhibited weed growth as the dose was increased up to about 20 ppbw. GR50values were 16, 16, 11, and 31 ppbw for cheat, downy brome, Japanese brome, and jointed goatgrass, respectively. Japanese brome was more susceptible than cheat or downy brome, and jointed goatgrass tolerated two to three times more MON 37500 than theBromusspecies. Plant dry weights of kochia seeded after removal of the winter annual grasses decreased with increasing initial MON 37500 concentrations up to 20 ppbw. Kochia density was influenced by which winter annual grass was grown previously.

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Winter Annual Grass Control in Winter Wheat

Kansas Agricultural Experiment Station Research Reports ◽

10.4148/2378-5977.7446 ◽

2017 ◽

Vol 3 (6) ◽

Cited By ~ 1

Author(s):

D. E. Peterson ◽

C. Thompson ◽

C. L. Minihan

Keyword(s):

Winter Wheat ◽

Annual Grass ◽

Winter Annual

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Cropping Systems Control Winter Annual Grass Weeds in Winter Wheat

jpa ◽

10.2134/jpa1995.0535 ◽

1995 ◽

Vol 8 (4) ◽

pp. 535-539 ◽

Cited By ~ 40

Author(s):

Drew J. Lyon ◽

David D. Baltensperger

Keyword(s):

Winter Wheat ◽

Cropping Systems ◽

Annual Grass ◽

Winter Annual ◽

Systems Control

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Characterizing traits that enhance the competitiveness of winter wheat (Triticum aestivum) against jointed goatgrass (Aegilops cylindrica)

Weed Science ◽

10.1017/s0043174500090688 ◽

1999 ◽

Vol 47 (1) ◽

pp. 74-80 ◽

Cited By ~ 49

Author(s):

Alex G. Ogg ◽

Steven S. Seefeldt

Keyword(s):

Winter Wheat ◽

Seed Production ◽

Latent Variables ◽

Annual Grass ◽

Aegilops Cylindrica ◽

Growing Seasons ◽

Jointed Goatgrass ◽

Important Trait ◽

Winter Annual ◽

Grass Weed

Our objective was to identify traits in winter wheat important to competitiveness against jointed goatgrass, measured as increased wheat yields and reduced jointed goatgrass seed production. Jointed goatgrass is an important winter annual grass weed that cannot be controlled selectively in winter wheat. Seven cultivars of soft white winter wheat were grown with and without competition from jointed goatgrass over two growing seasons. Measurements of numerous traits of winter wheat and jointed goatgrass were recorded throughout each growing season. The data were analyzed using path analysis with latent variables to determine which traits most enhanced competitiveness. In a drier year, increased rate of height development was important in maintaining wheat yields when wheat was growing in competition with jointed goatgrass. Increased rate of height development also was an important trait in reducing jointed goatgrass seed production. In a wet year compared to a dry year, the number of wheat heads per plant, the rate of water use, and weight gain were positively correlated to maintaining winter wheat yields. Jointed goatgrass seed production in the wet year was reduced overall compared to the dry year, but from the cultivars tested, there were no traits identified that were critical in enhancing this loss of seed production. This study suggests that cultivars with greater height development rates will be more competitive when growing in fields infested with jointed goatgrass.

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Yellow Brazilian Pepper-tree Leaf Galler (suggested common name) Calophya latiforceps Burckhardt (Insecta: Hemiptera: Calophyidae: Calophyinae)

EDIS ◽

10.32473/edis-in1186-2017 ◽

2017 ◽

Vol 2017 (6) ◽

Author(s):

James P. Cuda ◽

Patricia Prade ◽

Carey R. Minteer-Killian

Keyword(s):

Biological Control ◽

North America ◽

Natural Enemies ◽

Host Plants ◽

Classical Biological Control ◽

Biological Control Agents ◽

Pepper Tree ◽

Brazilian Pepper ◽

Close Relatives ◽

Tree Leaf

In the late 1970s, Brazilian peppertree, Schinus terebinthifolia Raddi (Sapindales: Anacardiaceae), was targeted for classical biological control in Florida because its invasive properties (see Host Plants) are consistent with escape from natural enemies (Williams 1954), and there are no native Schinus spp. in North America. The lack of native close relatives should minimize the risk of damage to non-target plants from introduced biological control agents (Pemberton 2000). [...]

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