Aphid Alert 1999, No. 6, July 20

Summer 1999: Aphid trapping data.

Results reported in this issue of Aphid Alert are total captures of winged aphids and species identifications for the following locations and sampling interval end-dates. Data for missing locations will be incorporated into this week's issue of the newsletter as the data becomes available.

During the week ending 20 July, green peach aphid captures remained at essentially the same level per trap as in the previous week. We anticipate green peach captures in the traps will remain relative stable until they start moving from potatoes. This begin in early August as the potato crop matures and aphid numbers on commericial potato production increases. Captures of PVY vectors (counts here include potato aphid, but not green peach aphid) increased about 45% over the previous week. This increase in PVY vectors probably reflects the maturation of small grains and canola causing the insects to seek alternative hosts.

We have been contacted by several seed potato growers interested in the use of mineral oils as a possible means of reducing the spread of PVY. For more information on this see Robert Suranyi's report, Crop borders and Mineral Oil: Two tactics for management of PVY in seed potatoes.

Summary of aphid captures per trap in 1999 compared to same dates in 1998

Aphids captured per trap (mean all locations)

1998

1999

Week ending PVY vectors* GPA
5-Jul 0.22 0
12-Jul 0.86 0.04
19-Jul 7.75 0.19
27-Jul 22.26 0.69
2-Aug 27.92 0.69
9-Aug 83.97 0.42
16-Aug 223.76 2.2
23-Aug 53.15 2.08
30-Aug 67.34 2.88
5-Sep 28.77 1.92
13-Sep 8.13 0.26
20-Sep 3.75 0.4
27-Sep 1.75 0
4-Oct 2.28 0.08
Week ending PVY vectors* GPA 
14-Jun 0.36 0
22-Jun 2.08 0.03
29-Jun 2.94 0.06
6-Jul 4.27 0.27
13-Jul 5.08 0.51
20-Jul 10.86 0.56

*GPA not included in PVY vectors

We maintain a list of e-mail addresses to facilitate communication with those of you interested in receiving updates about this research or any resulting advisories sooner than this information can be delivered by mail or even before it is posted on the WWW. If you wish your name added to receive such messages please send us an e-mail at radcl001@umn.edu. In the message, write "Aphid Alert subscribe."

Errors: If you find errors, typographic or factual, we would appreciate having them called to our attention so they can be corrected. Phone: Robert Suranyi (218) 773-3346 or Ted Radcliffe (612) 624-773 or send an e-mail to radcl001@umn.edu.

 

Results

Minnesota: Baker, Climax, Gully, Hollandale, Karlstad, Little Falls, Morris, Williams
North Dakota: Cando, Hoople, Linton, Mandan, Rolette, Walhalla

Baker, MN, week ending 19 July

  Aphid species # captured % of total capture
PLRV/PVY vectors green peach aphid    
  potato aphid 1 3
       
PVY vectors bird cherry-oat aphid 2 6.1
  corn leaf aphid 1 3
  English grain aphid    
  greenbug    
  sunflower aphid 3 9.1
  thistle aphid 3 9.1
  turnip aphid 9 27.3
       
Identified non-vector species   4 12.1
       
Unidentified   10 30.3
       
  Total 33  

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Climax, MN, week ending 20 July (based on a sample of 183 aphids)

  Aphid species # captured * % of total capture
PLRV/PVY vectors green peach aphid 4 (6) 2.2
  potato aphid 2 (3) 1.1
       
PVY vectors bird cherry-oat aphid 2 (3) 1.1
  corn leaf aphid    
  English grain aphid 2 (3) 1.1
  greenbug    
  sunflower aphid 98 (134) 53.6
  thistle aphid 15 (21) 8.2
  turnip aphid 21 (29) 11.5
       
Identified non-vector species   6 (8) 3.3
       
Unidentified   33 (45) 18
       
  Sorted / Total * 183 / 251  

*Actual numbers in sorted subsample (projected numbers in total collection)

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Gully, MN, week ending 19 July

  Aphid species # captured % of total capture
PLRV/PVY vectors green peach aphid 5 11.4
  potato aphid 1 2.3
       
PVY vectors bird cherry-oat aphid 5 11.4
  corn leaf aphid    
  English grain aphid 5 11.4
  greenbug    
  sunflower aphid    
  thistle aphid 10 22.7
  turnip aphid 11 25
       
Identified non-vector species   3 6.8
       
Unidentified   4 9.1
       
  Total 44  

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Hollandale, MN, week ending 20 July

  Aphid species # captured % of total capture
PLRV/PVY vectors green peach aphid    
  potato aphid 1 14.3
       
PVY vectors bird cherry-oat aphid    
  corn leaf aphid    
  English grain aphid    
  greenbug    
  sunflower aphid    
  thistle aphid 1 14.3
  turnip aphid 1 14.3
       
Identified non-vector species   3 42.9
       
Unidentified   1 14.3
       
  Total 7  

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Karlstad, MN, week ending 21 July

  Aphid species # captured % of total capture
PLRV/PVY vectors green peach aphid    
  potato aphid    
       
PVY vectors bird cherry-oat aphid    
  corn leaf aphid 1 2.1
  English grain aphid 2 4.2
  greenbug 1 2.1
  sunflower aphid 8 16.7
  thistle aphid 11 22.9
  turnip aphid 13 27.1
       
Identified non-vector species   7 14.6
       
Unidentified   5 10.4
       
  Total 48  

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Little Falls, MN, week ending 19 July

  Aphid species # captured % of total capture
PLRV/PVY vectors green peach aphid    
  potato aphid 5 17.9
       
PVY vectors bird cherry-oat aphid 11 39.3
  corn leaf aphid 2 7.1
  English grain aphid 1 3.6
  greenbug    
  sunflower aphid    
  thistle aphid 1 3.6
  turnip aphid 4 14.3
       
Identified non-vector species   2 7.1
       
Unidentified   2 7.1
       
  Total 28  

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Morris, MN, week ending 21 July

  Aphid species # captured % of total capture
PLRV/PVY vectors green peach aphid 6 8.1
  potato aphid 3 4.1
       
PVY vectors bird cherry-oat aphid 2 2.7
  corn leaf aphid 1 1.4
  English grain aphid    
  greenbug    
  sunflower aphid    
  thistle aphid 48 64.9
  turnip aphid 4 5.4
       
Identified non-vector species   6 8.1
       
Unidentified   4 5.4
       
  Total 74  

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Williams, MN, week ending 19 July

  Aphid species # captured % of total capture
PLRV/PVY vectors green peach aphid    
  potato aphid    
       
PVY vectors bird cherry-oat aphid 9 21.4
  corn leaf aphid    
  English grain aphid    
  greenbug    
  sunflower aphid    
  thistle aphid 18 42.9
  turnip aphid    
       
Identified non-vector species   4 9.5
       
Unidentified   11 26.2
       
  Total 42  

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Cando, ND, week ending 16 July

  Aphid species # captured % of total capture
PLRV/PVY vectors green peach aphid    
  potato aphid    
       
PVY vectors bird cherry-oat aphid 6 22.2
  corn leaf aphid    
  English grain aphid 1 3.7
  greenbug    
  sunflower aphid 5 18.5
  thistle aphid 5 18.5
  turnip aphid 4 14.8
       
Identified non-vector species   1 3.7
       
Unidentified   5 18.5
       
  Total 27  

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Hoople, ND, week ending 16 July

  Aphid species # captured % of total capture
PLRV/PVY vectors green peach aphid 2 3.9
  potato aphid    
       
PVY vectors bird cherry-oat aphid 18 35.3
  corn leaf aphid    
  English grain aphid    
  greenbug    
  sunflower aphid 7 13.7
  thistle aphid 3 5.9
  turnip aphid 3 5.9
       
Identified non-vector species   4 7.8
       
Unidentified   14 27.5
       
  Total 51  

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Linton, ND, week ending 18 July

  Aphid species # captured % of total capture
PLRV/PVY vectors green peach aphid 11 5.1
  potato aphid 12 5.6
       
PVY vectors bird cherry-oat aphid 5 2.3
  corn leaf aphid 13 6.1
  English grain aphid 2 0.9
  greenbug    
  sunflower aphid 7 3.3
  thistle aphid 1 0.5
  turnip aphid 103 47.9
       
Identified non-vector species   49 22.8
       
Unidentified   12 5.6
       
  Total 215  

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Mandan, ND, week ending 18 July

  Aphid species # captured % of total capture
PLRV/PVY vectors green peach aphid 7 6.3
  potato aphid 9 8
       
PVY vectors bird cherry-oat aphid 21 18.8
  corn leaf aphid    
  English grain aphid 1 0.9
  greenbug    
  sunflower aphid 4 3.6
  thistle aphid 10 8.9
  turnip aphid 45 40.2
       
Identified non-vector species   8 7.2
       
Unidentified   7 6.3
       
  Total 112  

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Rolette, week ending 16 July

  Aphid species # captured % of total capture
PLRV/PVY vectors green peach aphid    
  potato aphid 2 7.1
       
PVY vectors bird cherry-oat aphid 12 42.9
  corn leaf aphid 1 3.6
  English grain aphid    
  greenbug    
  sunflower aphid 2 7.1
  thistle aphid    
  turnip aphid 3 10.7
       
Identified non-vector species   3 10.7
       
Unidentified   5 17.9
       
  Total 28  

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Walhalla, ND, week ending 15 July

  Aphid species # captured % of total capture
PLRV/PVY vectors green peach aphid    
  potato aphid 1 9.1
       
PVY vectors bird cherry-oat aphid 2 18.2
  corn leaf aphid    
  English grain aphid 1 9.1
  greenbug    
  sunflower aphid    
  thistle aphid 2 18.2
  turnip aphid 3 27.3
       
Identified non-vector species   1 9.1
       
Unidentified   1 9.1
       
  Total 11  

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