Aphid Alert

No. 10, 2000
13 August

Published cooperatively by
departments of Entomology & Plant Pathology,
College of Agricultural, Food and Environmental Sciences, University of Minnesota,
the University of Minnesota Extension Service,
and the State Seed Potato Programs of 
Minnesota and North Dakota

Funding provided by:
Minnesota State Legislature &
United States Department of Agriculture,
Cooperative State Research, Education and Extension Service,
Integrated Pest Management Program,
North Central Region

WWW address: http://ipmworld.umn.edu/alert.htm

Update: Summary of virus vector situation through 13 August.

Update: Summary of virus vector situation through 13 August.

Captures of winged aphids in the Aphid Alert network traps were roughly double  that of last week (144.5 per trap compared to 74.3). Captures of green peach aphid averaged 1.19 per trap compared to 0.55 per trap last week.   Some locations in North Dakota averaged 3.0 green peach aphids per trap.   Turnip aphid numbers also increased about 4.5-fold (to a mean of 19 per trap).   Green peach aphid and turnip aphid are commonly found in large numbers on canola.   Most canola has been swathed, but late planted fields still host high numbers of green peach aphid and most of the immatures will develop into winged adults.  Corn leaf aphid remains very abundant in many locations, but this species is not important as a PVY vector.

Last week, we noted reports of an aphid attacking soybean in Michigan and Illinois.  It since has been determined that this aphid is Aphis glycines, an Asiatic soybean pest.  This unwanted immigrant is very similar in appearance to Aphis gossypii (melon or cotton aphid).   Aphis glycines is native to northern China and Siberia so it unlikely to be limited by cold winter temperatures.   We suspect that Aphis glycines will prove capable of transmitting PVY.   That might reduce the value of soybean as a crop border for protection of elite potato seed lots from PVY, but small grains have proven effective as crop borders even though they host aphids capable of vectoring PVY.  A problem would only exist if the there was some virus already present in the field you were trying to protect.

We continue to hear reports or grower dissatisfaction with the aphid control  obtained using Fulfill (pymetrozine). Performance seems most problematic when low volume applications are made, especially with those applied by air.  There is some suspicion that potato aphid may be more difficult to control that green peach aphid.  In our insecticide efficacy trials at Rosemount, we have had good success with this product against both ot these aphids.  We have tested the product under extreme green peach aphid pressure giving us considerable confidence in that data; typically we get >98% control.  In our experiments,   potato aphid pressure has been too low to severely test the product, but we are getting >90% control.  Fulfill kills aphids very slowly (5-7 days may be required before the insect dies), but feeding activity ceases almost immediately. However, it may be that if application does not penetrate the canopy that UL light may reduce the effective life of the product.

Captures of winged aphids (mean number per trap), 1992-1994 & 1998-2000, Data for Minnesota and North Dakota locations in the Aphid Alert trapping network.
	Fig. 1. Captures of winged green peach aphid per trap.
	Fig. 2. Captures potential PVY vectors other than green peach aphid per trap.
	Fig. 3. Captures of winged turnip aphid per trap.
	Fig. 4. Captures of winged small grain aphids (i.e., bird cherry-oat aphid, English grain aphid and greenbug) per trap.
	Fig. 5. Captures of sunflower aphid per trap.
	Fig. 6. Captures of other potential PVY vectors (including potato aphid, corn leaf aphid, thistle aphid, and others) per trap.

Visit Jeff Miller's Late Blight Site

Trap locations in 2000

Status of Aphid Alert project

MINNESOTA

Baker
14 August

Climax
15 August

Crookston
14 August

Gully
14 August

Hollandale

Aphids per trap per week

Species

PLRV/PVY vectors  

green peach aphid

2 (2.7)

4 (0.8)

4 (2.2)

1 (0.9)

potato aphid

PVY vectors

bird cherry-oat aphid

2 (2.7)

2 (0.4)

1 (0.5)

2 (1.8)

corn leaf aphid

22 (29.3)

2 (0.4)

47 (42.7)

English grain aphid

1 (0.2)

2 (1.8)

greenbug

sunflower aphid

1 (0.2)

1 (.5)

10 (9.1)

thistle aphid

4 (5.3)

1 (0.2)

8 (4.4)

3 (2.7)

turnip aphid

18 (24)

459 (33.7)

142 (77.2)

9 (8.2)

Other PVY vectors

2 (2.7)

3 (0.6)

3 (2.7)

Non-vectors and unidentified

non-vectors

18 (24)

10 (2)

4 (2.2)

17 (15.5)

unidentified

5 (6.7)

7 (1.4)

10 (5.4)

16 (14.6)

Totals

75

490

184

No data

110

No data

Karlstad
14 August

Little Falls

Rice
14 August

Rosemount
14 August

Thief River

Williams
14 August

Aphids per trap per week

PLRV/PVY vectors

1 (9.1)

3 (2.2)

1 (9.1)

PVY vectors

1 (9.1)

5 (3.7)

4 (36.4)

100 (74.1)

82 (67.8)

1 (9.1)

3 (2.5)

1 (9.1)

1 (0.7)

2 (1.7)

1 (9.1)

3 (2.2)

13 (10.7)

Other PVY vectors

9 (6.7)

3 (2.5)

Non-vectors and unidentified

non-vectors

1 (9.1)

2 (1.5)

13 (10.7)

unidentified

12 (8.9)

5 (4.1)

Totals

11

No data

No data

135

No data

121

Cando
11 August

Hoople
11 August

Linton
14 August

Mandan
14 August

Minot
9 August

Rolette
11 August

Walhalla
11 August

Aphids per trap per week

PLRV/PVY vectors

7 (12.3)

1 (0.7)

2 (1.3)

9 (7.6)

7 (11.3)

9 (2.6)

1 (0.7)

1 (0.7)

4 (3.4)

2 (0.6)

PVY vectors

4 (7)

1 (3.3)

3 (2.2)

9 (6.0)

3 (2.5)

27 (43.6)

10 (2.9)

23 (40.4)

20 (66.7)

77 (56.6)

99 (66.0)

34 (28.8)

207 (60.2)

3 (5.3)

1 (0.7)

1 (0.7)

8 (6.8)

2 (3.2)

11 (3.2)

1 (0.7)

1 (3.3)

1 (0.3)

5 (8.8)

5 (3.7)

5 (3.3)

10 (8.5)

3 (4.8)

9 (2.6)

10 (17.5)

8 (26.7)

31` (22.8)

15 (10)

26 (22)

13 (21)

48 (14)

4 (2.9)

1 (0.7)

9 (7.6)

30 (8.7)

Non-vectors and unidentified

4 (7)

4 (2.9)

2 (1.3)

7 (5.9)

5 (8.1)

8(2.3)

1 (1.8)

7 (5.2)

15 (10)

8 (6.8)

5 (8.1)

9 (2.6)

57

30

136

150

118

62

344