Aphid Alert 2000, No. 5, July 9

Update: Summary of virus vector situation through 9 July

To date, aphid captures in the Aphid Alert network traps have been few. Only four green peach aphids have been collected, one each at Little Falls - 26 June, Climax - 3 July, Walhalla - 7 July, and Karlstad - 10 July. On this date in 1998 and 1999, we were averaging 0.5-0.75 green peach aphid per trap.

Other aphid species (most of which are potential PVY vectors) have been more abundant, but during the week ending 14 July total captures were still in the range of 0-35 per location (i.e., 0-12 per trap).

It is possible that some locations aphids were lost from pan traps flooded by heavy rains. Note: In Minnesota, North Dakota and Wisconsin, we operate one suction trap and two pan traps at each location. Our cooperators in Nebraska and South Dakota operate a suction trap only.

Our team in the Red River Valley reports that many canola fields now have moderate to heavy infestations of green peach aphid. These populations do not appear to be as large as large as occurred last year. However, green aphid numbers likely will to continue to increase for the next several weeks.

Much of the canola in the Valley is past flowering and the lower leaves are beginning to senesce. We anticipate that as the canola matures, captures of green peach aphid captures in our traps will increase sharply.

Small grains are now maturing and it does not appear that these crops are supporting large aphid populations. Cereal aphids are potential PVY vectors, so their comparative low numbers are good news.

Aphid captures per trap by location for week ending 9 July

Minnesota

Minnesota Baker
10 July
Climax
10 July
Crookston
10 July
Gully
10 July
Hollandale
12 July
Karlstad
10 July
  Aphids per trap per week
Species PLRV/PVY vectors  
green peach aphid           1 (9.1)
potato aphid 1 (2.9) 1 (9.1)       2 (18.2)
  PVY vectors
bird cherry-oat aphid 6 (17.1) 3 (27.3) 1 (8.3)      
corn leaf aphid         1 (16.7)  
English grain aphid 2 (5.7)       1 (16.7)  
greenbug            
sunflower aphid            
thistle aphid 2 (5.7) 1 (9.1) 4 (33.3) 1 (9.1) 1 (16.7)  
turnip aphid   1 (9.1) 2 (16.7) 2 (18.2) 2 (33.3) 2 (18.2)
Other PVY vectors            
  Non-vectors and unidentified
non-vectors 19 (54.3) 4 (36.4) 3 (25) 5 (45.5) 1 (16.7) 4 (36.4)
unidentified 5 (14.3) 1 (9.1) 2 (16.7) 3 (27.3)    
Totals 35 11 12 11 6 11

Minnesota

Minnesota Little Falls
10 July
Morris
10 July
Rice
11 July
Rosemount
10 July
Thief River
11 July
Williams
10 July
  Aphids per trap per week
Aphid species PLRV/PVY vectors
green peach aphid            
potato aphid 1 (7.1)       1 (6.7) 1 (6.7)
  PVY vectors
bird cherry-oat aphid 5 (35.7)   2 (13.3)      
corn leaf aphid     1 (6.7)     2 (13.3)
English grain aphid           2 (13.3)
greenbug            
sunflower aphid         5 (33.3) 1 (6.7)
thistle aphid     2 (13.3)   7 (46.7) 2 (13.3)
turnip aphid            
Other PVY vectors            
  Non-vectors and unidentified
non-vectors 4 (28.6)   6 (40) 1 (100) 2 (13.3) 7 (46.7)
unidentified 4 (28.6)   4 (26.7)      
Totals 14 0 15 1 15 15

North Dakota

North Dakota Cando
7 July
Hoople
7 July
Linton
10 July
Mandan
10 July
Minot
10 July
Rolette
7 July
Walhalla
7 July
  Aphids per trap per week
Aphid species PLRV/PVY vectors
green peach aphid             1 (8.3)
potato aphid         2 (5.3)    
PVY vectors
bird cherry-oat aphid   1 (6.7)          
corn leaf aphid 1 (25.0) 7 (46.7)     4 (10.5)    
English grain aphid         1 (2.6)    
greenbug   1 (6.7)          
sunflower aphid              
thistle aphid              
turnip aphid         3 (7.9)    
other PVY vectors              
Non-vectors and unidentified
non-vectors 3 (75) 5 (33.3)     28 (73.6) 8 (88.9) 7 (58.3)
unidentified   1 (6.7)         1 (8.3)
Totals 4 15 0 0 38 9 12

Wisconsin

Wisconsin Antigo
19 June
Rhinelander
19 June
  Aphids per trap per week
Aphid species PLRV/PVY vectors
green peach aphid    
potato aphid    
  PVY vectors
bird cherry-oat aphid    
corn leaf aphid   1 (100)
English grain aphid    
greenbug    
sunflower aphid    
thistle aphid    
turnip aphid    
other PVY vectors    
  Non-vectors and unidentified
non-vectors 1 (100)  
unidentified    
Totals 1 1

South Dakota

South Dakota Watertown
10 July
  Aphids per trap per week
Aphid species PLRV/PVY vectors
green peach aphid  
potato aphid  
  PVY vectors
bird cherry-oat aphid 2 (33.3)
corn leaf aphid 1 (16.7)
English grain aphid  
greenbug  
sunflower aphid  
thistle aphid  
turnip aphid 1 (16.7)
other PVY vectors  
  Non-vectors and unidentified
non-vectors 2 (33.3)
unidentified  
Totals 6

Nebraska

Nebraska Cody
11 July
  Aphids per trap per week
Aphid species PLRV/PVY vectors
green peach aphid  
potato aphid  
  PVY vectors
bird cherry-oat aphid  
corn leaf aphid  
English grain aphid  
greenbug  
sunflower aphid  
thistle aphid  
turnip aphid  
other PVY vectors  
  Non-vectors and unidentified
non-vectors  
unidentified  
Totals