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 |