effect of winter annual weedeffect of winter annual weed ... · nematode population and...

Effect of Winter Annual WeedEffect of Winter Annual Weed Management on Soybean Cyst

Nematode Population and WeedNematode Population and Weed Density

Valerie A. Mock J. Earl Creech William G. Johnson

Soybean Cyst Nematode (SCN)

• Endoparasitic roundworm• Endoparasitic roundworm• Cysts can produce up to600 eggsgg

• Can complete lifecycle in28 days under optimal fieldconditions

• Reported in 82 of 92counties in Indiana*counties in Indiana*

• Yield loss

* Faghihi, J., and V.R. Ferris. 2006. http://www.entm.purdue.edu/Entomology/ext/targets/e-series/EseriesPDF/E-210.pdf.

Winter Annual Weeds

Winter Annual Weed Hosts

Purple deadnettle Henbit Field pennycress

Shepherd’s-purse Common chickweed

Smallflowered bittercress

Cool Season Perennial Host

Mouseear chickweed

SCN and Winter Annual Weeds• Winter annual weed survey-20041

- Indiana fields with SCN were sampled- Found 93% of fields had winter annual weedFound 93% of fields had winter annual weedhosts

• Field experiment: SCN can complete its lifecycle onpurple deadnettle 2purple deadnettle.

• Growth chamber experiment: Juveniles survivedperiods of cold temperature in roots and continued development when temperatures warmed 3development when temperatures warmed.3

1Creech, J.E., and W.G. Johnson. 2006. Weed Tech. 20:1066-1075.2Creech, J.E., W.G. Johnson, J.Faghihi, V.R. Ferris, and A. Westphal. 2005. Crop Management.3Creech, J.E., J.B. Santini, S.P. Conely, A. Westphal, and W.G. Johnson. 2007. Weed Science. 55:592-598.

SCN Management

C i i h h• Crop rotation with non-hostcrop

• SCN-resistant soybean

• Weed management??

Objective

To determine if winter annual weedd iti d SCN l ti d itidensities and SCN population densities can be reduced by using winter covercrops or herbicidescrops or herbicides.

Materials & Method‘s• Experiment established in2003 (2006-2008)

West Lafayette

( )• 2 locations

- Northern site - W. LafayetteCh l ilt l l

yChalmers silty clay loamLow weed density and SCN

Vincennes

SCN- Southern site - Vincennes

Patton silt loam Vincennes

High weed density andSCN

Materials & Method‘s

• 2 crop rotations- Soybean - soybeany y- Soybean - corn

• 6 weed management tactics: - Untreated- Untreated- Spring + fall glyphosatetreatments (Weed free)S i l h t- Spring glyphosatetreatment

- Fall glyphosate treatmentg y- Wheat cover crop- Annual ryegrass covercrop (ARG)crop (ARG)

Data collection

SCN egg counts- Spring and fall 2007- Sieving and decanting*

Weed counts- Fall 2006-07

nematology.umd.edu/scn.html (McGawley)

Fall 2006 07- Spring 2007-08- Quadrats

* Faghihi, J., and J.M. Ferris. 2000. J. Nematol. 32:411-413.

Data analysis

PROC MIXED- Locations analyzed separately- Locations analyzed separately- All data were log transformed- Means separated at P=0.05p- Back-transformed means will bepresented for clarity

Northern SCN egg counts (no. / 100 cc of soil)Weed management * rotation * season

S (C)* S (S)

Weed management rotation seasonP=0.0145

Weed mgmt. Spring‘07

Fall‘07

Spring‘07

Fall‘07

/ 100 f il_________ no. / 100 cc of soil _________

UntreatedWheatWheatARGFall ‘06 (F)Fall 06 (F)F + S Spring ‘07 (S)p g ( )

* Spring 2007 corn planted


S (C)* S (S)



Fall‘07

Spring‘07

Fall‘07

/ 100 f il_________ no. / 100 cc of soil _________

Untreated 0 bWheat 6 abWheat 6 abARG 4 abFall ‘06 (F) 11 abFall 06 (F) 11 abF + S 4 abSpring ‘07 (S) 16 ap g ( )



S (C)* S (S)



Fall‘07

Spring‘07

Fall‘07

/ 100 f il_________ no. / 100 cc of soil _________

Untreated 0 b 10 aWheat 6 ab 0 aWheat 6 ab 0 aARG 4 ab 4 aFall ‘06 (F) 11 ab 1 aFall 06 (F) 11 ab 1 aF + S 4 ab 5 aSpring ‘07 (S) 16 a 0 ap g ( )



S (C)* S (S)



Fall‘07

Spring‘07

Fall‘07

/ 100 f il_________ no. / 100 cc of soil _________

Untreated 0 b 10 a 1 aWheat 6 ab 0 a 2 aWheat 6 ab 0 a 2 aARG 4 ab 4 a 4 aFall ‘06 (F) 11 ab 1 a 2 aFall 06 (F) 11 ab 1 a 2 aF + S 4 ab 5 a 2 aSpring ‘07 (S) 16 a 0 a 0 ap g ( )



S (C)* S (S)



Fall‘07

Spring‘07

Fall‘07

/ 100 f il_________ no. / 100 cc of soil _________

Untreated 0 b 10 a 1 a 6 bWheat 6 ab 0 a 2 a 47 abWheat 6 ab 0 a 2 a 47 abARG 4 ab 4 a 4 a 30 abFall ‘06 (F) 11 ab 1 a 2 a 161 aFall 06 (F) 11 ab 1 a 2 a 161 aF + S 4 ab 5 a 2 a 39 abSpring ‘07 (S) 16 a 0 a 0 a 46 abp g ( )


SCN Conclusions• S(C) rotation in spring

- Higher SCN egg counts in spring timingthan untreated

- SCN eggs may have hatched in untreatedl tplots

• S(S) rotation in the fall• S(S) rotation in the fall- Higher SCN in fall timing than untreated- Winter annual weeds may serve as trap cropy p p

• Cover crops not effective in reducing SCNpopulations

Spring weed counts (Northern)

50

60

40

50

r m

2

30

ds

pe

10

20

Weed

0

10

Unt. ARG Wheat Fall gly.


50

60a

40

50

r m

2

b b30

ds

pe b b

10

20

Weed

0

10c



50

60

40

50

r m

2

30

ds

pe

a a

10

20

Weed a a a

0

10b



50

60

40

50

r m

2

a30

ds

pe

aa

a

aa a

10

20

Weed a

b0

10b



50

60

40

50

r m

2

30

ds

pe

a aa

a

a

10

20

Weed a a a

a

0

10b b

ba

bc


Spring weed counts (Southern)

240

160

200

r m

2

120

160

ds

pe

40

80

Weed

0

40



240a

a a

160

200

r m

2

120

160

ds

pe

40

80

Weed

0

40 b



240

160

200

r m

2

120

160

ds

pe

40

80

Weed

ba a

0

40c



240

160

200

r m

2

120

160

ds

pe

aab

40

80

Weed

ba a

bab

0

40c c



240

160

200

r m

2

a

120

160

ds

pe

aab

a

a

40

80

Weed

ba a

bab

b

0

40c c c


Spring Weed Count Conclusions

• Fall glyphosate treatments provide betterweed suppression than cover crops.

• Annual ryegrass and wheat did not reduceSCN winter weed hostsSCN winter weed hosts.

• Winter weed hosts seem to compete betterthan the non-hosts with annual ryegrassthan the non hosts with annual ryegrassand wheat.

Future Research

T d t i if i t l d• To determine if winter annual weeds can:- Stimulate earlier egg hatch in spring- Serve as trap crops in the field- Serve as trap crops in the field- Increase soil microbes that suppressSCN

Questions??

effect of winter annual weedeffect of winter annual weed ... · nematode population and...

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