Abstract
It is now widely recognized that Bidens pilosa has become a problematic broadleaf weed in many ecosystems across the world and, particularly in the light of recent climate change conditions, closer management strategies are required to curtail its impact on agricultural cropping. In this investigation, experiments were conducted to evaluate the effect of environmental factors on the germination and emergence of B. pilosa, and also on the response of this weed to commonly available post-emergence herbicides in Australia. The environmental factors of particular interest to this current work were the effect of light and temperature, salinity, burial depth and moisture on B. pilosa since these are key management issues in Australian agriculture. In addition, the effects of a number of commonly used herbicides were examined, because of concerns regarding emerging herbicide resistance. In the tested light/dark regimes, germination was found to be higher at fluctuating day/night temperatures of 25/15 °C and 30/20 °C (92-93%) than at 35/25 °C (79%), whilst across the different temperature ranges, germination was higher in the light/dark regime (79-93%) than in complete darkness (22-38%). The standard five-minute temperature pretreatment required for 50% inhibition of maximum germination was found to be 160 °C, and it was further shown that no seeds germinated at temperatures higher than 240 °C. With regard to salinity, some B. pilosa seeds germinated (3%) in 200 mM sodium chloride (NaCl) but all failed to germinate at 250 mM NaCl. Germination declined from 89% to 2% as the external osmotic potential decreased from 0 to -0.6 MPa, and germination ceased at -0.8 MPa. Seeding emergence of B. pilosa was maximum (71%) for seeds placed on the soil surface and it was found that no seedlings emerged from a depth of 8 cm or greater. A depth of 3.75 cm was required to inhibit the seeds to 50% of the maximum emergence. In this study, application of glufosinate, glyphosate and paraquat provided commercially acceptable control levels (generally accepted as >90%) when applied at the four-leaf stage of B. pilosa. However, none of the herbicide treatments involved in this study provided this level of control when applied at the six-leaf stage. In summary, B. pilosa germination has been clearly shown to be stimulated by light and thus its emergence was greatest from the soil surface. This suggests that infestation from this weed will remain as a problem in no-till conservation agriculture systems, the use of which is increasing now throughout the world. It is intended that information generated from this study be used to develop more effective integrated management programs for B. pilosa and similar weeds in commercial agricultural environments which are tending toward conservation approaches.
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Claims 17
Claim · model-written summary
Germination was higher at 25/15 and 30/20 °C than at 35/25 °C.
- Taxon
- Bidens pilosa
Bidens pilosat0 - Treatment
- 25/15 °C and 30/20 °Ce0
- Outcome
- germinatione0
- Direction
- highere0
- Value
- 92-93%e0
- Qualifier
- 79%e0
- Comparator
- 35/25 °Ce0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“germination was found to be higher at fluctuating day/night temperatures of 25/15 °C and 30/20 °C (92-93%) than at 35/25 °C (79%)”
t0“Bidens pilosa”
Claim · model-written summary
Germination was higher under light/dark than complete darkness.
- Taxon
- Bidens pilosaBidens pilosat0
- Treatment
- light/dark regimee0
- Outcome
- germinatione0
- Direction
- highere0
- Value
- 79-93%e0
- Qualifier
- 22-38%e0
- Comparator
- complete darknesse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“germination was higher in the light/dark regime (79-93%) than in complete darkness (22-38%)”
t0“Bidens pilosa”
Claim · model-written summary
A five minute 160 °C pretreatment inhibited half of maximum germination.
- Taxon
- Bidens pilosaBidens pilosat0
- Treatment
- five-minute temperature pretreatmente0
- Outcome
- maximum germinatione0
- Direction
- inhibitione0
- Value
- 50%e0
- Qualifier
- 160 °Ce0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The standard five-minute temperature pretreatment required for 50% inhibition of maximum germination was found to be 160 °C”
t0“Bidens pilosa”
Claim · model-written summary
No seeds germinated above 240 °C.
- Taxon
- Bidens pilosaBidens pilosat0
- Treatment
- temperatures higher than 240 °Ce0
- Outcome
- no seeds germinatede0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“no seeds germinated at temperatures higher than 240 °C”
t0“Bidens pilosa”
Claim · model-written summary
Three percent of seeds germinated at 200 mM NaCl.
- Taxon
- Bidens pilosaBidens pilosat0
- Treatment
- 200 mM sodium chloride (NaCl)e0
- Outcome
- B. pilosa seeds germinatede0
- Value
- 3%e0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“some B. pilosa seeds germinated (3%) in 200 mM sodium chloride (NaCl)”
t0“Bidens pilosa”
Claim · model-written summary
No seeds germinated at 250 mM NaCl.
- Taxon
- Bidens pilosaBidens pilosat0
- Treatment
- 250 mM NaCle0
- Outcome
- failed to germinatee0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“all failed to germinate at 250 mM NaCl”
t0“Bidens pilosa”
Claim · model-written summary
Germination fell from 89% to 2% as osmotic potential fell from 0 to -0.6 MPa.
- Taxon
- Bidens pilosaBidens pilosat0
- Treatment
- external osmotic potentiale0
- Outcome
- Germinatione0
- Direction
- declinede0
- Value
- 89% to 2%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Germination declined from 89% to 2% as the external osmotic potential decreased from 0 to -0.6 MPa”
t0“Bidens pilosa”
Claim · model-written summary
Germination ceased at -0.8 MPa.
- Taxon
- Bidens pilosaBidens pilosat0
- Treatment
- -0.8 MPae0
- Outcome
- germination ceasede0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“germination ceased at -0.8 MPa”
t0“Bidens pilosa”
Claim · model-written summary
Surface placed seeds had maximum emergence of 71%.
- Taxon
- Bidens pilosaBidens pilosat0
- Outcome
- Seeding emergence of B. pilosae0
- Direction
- maximume0
- Value
- 71%e0
- Setting
- soil surfacee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Seeding emergence of B. pilosa was maximum (71%) for seeds placed on the soil surface”
t0“Bidens pilosa”
Claim · model-written summary
No seedlings emerged from at least 8 cm depth.
- Taxon
- Bidens pilosaBidens pilosat0
- Treatment
- a depth of 8 cm or greatere0
- Outcome
- no seedlings emergede0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“no seedlings emerged from a depth of 8 cm or greater”
t0“Bidens pilosa”
Claim · model-written summary
A 3.75 cm burial depth inhibited half of maximum emergence.
- Taxon
- Bidens pilosaBidens pilosat0
- Treatment
- A depth of 3.75 cme0
- Outcome
- maximum emergencee0
- Direction
- inhibite0
- Value
- 50%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A depth of 3.75 cm was required to inhibit the seeds to 50% of the maximum emergence”
t0“Bidens pilosa”
Claim · model-written summary
Glufosinate gave commercially acceptable control at the four leaf stage.
- Taxon
- Bidens pilosaBidens pilosat0
- Organ / stage
- four-leaf stagee0
- Treatment
- glufosinatee0
- Outcome
- control levelse0
- Value
- >90%e0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“application of glufosinate, glyphosate and paraquat provided commercially acceptable control levels (generally accepted as >90%) when applied at the four-leaf stage of B. pilosa”
t0“Bidens pilosa”
Claim · model-written summary
Glyphosate gave commercially acceptable control at the four leaf stage.
- Taxon
- Bidens pilosaBidens pilosat0
- Organ / stage
- four-leaf stagee0
- Treatment
- glyphosatee0
- Outcome
- control levelse0
- Value
- >90%e0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“application of glufosinate, glyphosate and paraquat provided commercially acceptable control levels (generally accepted as >90%) when applied at the four-leaf stage of B. pilosa”
t0“Bidens pilosa”
Claim · model-written summary
Paraquat gave commercially acceptable control at the four leaf stage.
- Taxon
- Bidens pilosaBidens pilosat0
- Organ / stage
- four-leaf stagee0
- Treatment
- paraquate0
- Outcome
- control levelse0
- Value
- >90%e0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“application of glufosinate, glyphosate and paraquat provided commercially acceptable control levels (generally accepted as >90%) when applied at the four-leaf stage of B. pilosa”
t0“Bidens pilosa”
Claim · model-written summary
None of the herbicides reached acceptable control at the six leaf stage.
- Taxon
- Bidens pilosaBidens pilosat0
- Organ / stage
- six-leaf stagee0
- Outcome
- this level of controle0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“none of the herbicide treatments involved in this study provided this level of control when applied at the six-leaf stage”
t0“Bidens pilosa”
Claim · model-written summary
Light stimulated germination.
- Taxon
- Bidens pilosaBidens pilosat0
- Treatment
- lighte0
- Outcome
- germinatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“B. pilosa germination has been clearly shown to be stimulated by light”
t0“Bidens pilosa”
Claim · model-written summary
The weed was predicted to remain problematic in no till conservation systems.
- Taxon
- Bidens pilosaBidens pilosat0
- Outcome
- infestation from this weed will remain as a problem in no-till conservation agriculture systemse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“infestation from this weed will remain as a problem in no-till conservation agriculture systems”
t0“Bidens pilosa”
The same questions in other papers
glyphosate · control · Bidens pilosa (bur-marigold)Results agree
1 paper in the same direction as this paper
- positive
light · growth · Bidens pilosa (bur-marigold)Positive and negative results
4 papers in the same direction as this paper · 1 in the opposite direction
- positive
- no effect
- positive
2 papers more in this group
See all 6 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.