Aphid Alert

No. 8, posted
8 August, 1999

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:
1998 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>

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.

Baker, MN 2 August	Climax, MN 2 August	Gully, MN 2 August	Hollandale, MN 3 August
Karlstad, MN 3 August	Little Falls, MN No data	Morris, MN 2 August	Williams, MN 3 August
Cando, MN 30 July	Hoople, ND 30 July	Linton, ND 1 August	Mandan, ND 1 August
Rolette, ND 30 July	Walhalla, ND 29 July

Figure 1 (below). Mean number of winged green peach aphid captured per trap across all locations reported, 1998 data (blue line) and 1999 data (maroon line). These data are also available in table format (Table 1).

Figure 2 (below). Mean number of winged aphids of species known to be capable of transmitting PVY (exclusive of green peach aphid) captured per trap across all locations reported, 1998 data (blue line) and 1999 data (maroon line). These data are also available in table format (Table 1).

Summary of observations for week ending 3 August.

The number of green peach aphids captured in our traps increased sharply during the past week. Numbers of this species have been consistently higher throughout 1999 than on comparable dates in 1998. Last week's green peach aphid captures were double that of the previous year on the same date. None of the green peach aphids tested to date (those captured through 27 Jul) have tested positive for PVY or PLRV, but the high numbers that are present are reason for concern. The other aphid species that are potential vectors of PVY remain at densities very comparable to what we observed in 1998. Numbers of these aphids are also increasing rapidly and can be expected to peak in the next week or two. We consider the risk of virus spread to be high at this time.

We are establishing 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

Baker, MN, week ending 2 August
	Aphid species	# captured	% of total capture
PLRV/PVY vectors	green peach aphid	8	10.3
	potato aphid

PVY vectors	bird cherry-oat aphid	4	5.1
	corn leaf aphid	4	5.1
	English grain aphid	1	1.3
	greenbug
	sunflower aphid
	thistle aphid	13	16.7
	turnip aphid	32	41.0

Identified non-vector species		7	9.0

Unidentified		9	11.5

	Total	78

Climax, MN, week ending 2 August
	Aphid species	# captured*	% of total capture
PLRV/PVY vectors	green peach aphid	7 (13)	4.3
	potato aphid

PVY vectors	bird cherry-oat aphid	6 (11)	3.7
	corn leaf aphid	5 (5)	1.9
	English grain aphid	1 (2)	0.6
	greenbug
	sunflower aphid	58 (104)	35.8
	thistle aphid	10 (18)	6.2
	turnip aphid	63 (113)	38.9

Identified non-vector species		5 (9)	3.1

Unidentified		9 (16)	5.6

	Sorted/Total*	162/290
*Actual numbers in sorted subsample (projected numbers in total collection)

Gully, MN, week ending 2 August
	Aphid species	# captured	% of total capture
PLRV/PVY vectors	green peach aphid
	potato aphid	1	0.9

PVY vectors	bird cherry-oat aphid
	corn leaf aphid	24	20.7
	English grain aphid	2	1.7
	greenbug
	sunflower aphid	12	10.3
	thistle aphid	2	1.7
	turnip aphid	54	46.6

Identified non-vector species		10	8.6

Unidentified		11	9.5

	Total	116

Hollandale, MN, week ending 3 August
	Aphid species	# captured	% of total capture
PLRV/PVY vectors	green peach aphid	1	2.1
	potato aphid

PVY vectors	bird cherry-oat aphid	3	6.4
	corn leaf aphid	27	57.4
	English grain aphid	1	2.1
	greenbug
	sunflower aphid
	thistle aphid	1	2.1
	turnip aphid

Identified non-vector species		7	14.9

Unidentified		7	14.9

	Total	47

Karlstad, MN, week ending 3 August
	Aphid species	# captured*	% of total capture
PLRV/PVY vectors	green peach aphid	9 (11)	5.9
	potato aphid	2 (3)	1.3

PVY vectors	bird cherry-oat aphid	6 (8)	3.9
	corn leaf aphid	6 (8)	3.9
	English grain aphid
	greenbug
	sunflower aphid	47 (59)	6.9
	thistle aphid	11 (14)	13.8
	turnip aphid	62 (78)	45.7

Identified non-vector species		3 (4)	2.0

Unidentified		6 (8)	17.2

	Sorted/Total*	152/191
*Actual numbers in sorted subsample (projected numbers in total collection)

Little Falls, MN, week ending 2 August
	Aphid species	# captured	% of total capture
Data not yet available

Morris, week ending 2 August
	Aphid species	# captured	% of total capture
PLRV/PVY vectors	green peach aphid	2	10.5
	potato aphid

PVY vectors	bird cherry-oat aphid
	corn leaf aphid	5	26.3
	English grain aphid
	greenbug
	sunflower aphid
	thistle aphid	2	10.5
	turnip aphid	7	36.8

Identified non-vector species		1	5.3

Unidentified		2	10.5

	Total	19

Williams, MN, week ending 3 August
	Aphid species	# captured	% of total capture
PLRV/PVY vectors	green peach aphid	2	1.3
	potato aphid

PVY vectors	bird cherry-oat aphid	7	4.7
	corn leaf aphid	50	33.3
	English grain aphid	2	1.3
	greenbug
	sunflower aphid	47	31.3
	thistle aphid	7	4.7
	turnip aphid	16	10.7

Identified non-vector species		6	4.0

Unidentified		13	8.7

	Total	150

Cando, week ending 30 July
	Aphid species	# captured	% of total capture
PLRV/PVY vectors	green peach aphid	2	4.3
	potato aphid	3	6.5

PVY vectors	bird cherry-oat aphid	5	10.9
	corn leaf aphid	10	21.7
	English grain aphid	1	2.2
	greenbug
	sunflower aphid
	thistle aphid	9	19.6
	turnip aphid	9	19.6

Identified non-vector species		4	8.7

Unidentified		3	6.5

	Total	46

Hoople, week ending 30 July
	Aphid species	# captured	% of total capture
PLRV/PVY vectors	green peach aphid	8	10.1
	potato aphid

PVY vectors	bird cherry-oat aphid	6	7.6
	corn leaf aphid	3	3.8
	English grain aphid
	greenbug
	sunflower aphid	3	3.8
	thistle aphid	8	10.1
	turnip aphid	26	32.9

Identified non-vector species		7	8.9

Unidentified		18	22.8

	Total	79

Linton, ND, week ending 1 August
	Aphid species	# captured*	% of total capture
PLRV/PVY vectors	green peach aphid	4 (9)	2.0
	potato aphid

PVY vectors	bird cherry-oat aphid
	corn leaf aphid	48 (106)	23.4
	English grain aphid
	greenbug
	sunflower aphid	13 (29)	6.3
	thistle aphid	1 (2)	0.5
	turnip aphid	129 (285)	62.9

Identified non-vector species		1 (2)	0.5

Unidentified		9 (20)	4.4

	Sorted/Total*	205/453
*Actual numbers in sorted subsample (projected numbers in total collection)

Mandan, ND, week ending 1 August
	Aphid species	# captured*	% of total capture
PLRV/PVY vectors	green peach aphid	11 (27)	4.7
	potato aphid	2 (5)	0.9

PVY vectors	bird cherry-oat aphid	4 (10)	1.7
	corn leaf aphid	2 (5)	0.9
	English grain aphid	1 (2)	0.4
	greenbug
	sunflower aphid	14 (34)	6.0
	thistle aphid	7 (17)	3.0
	turnip aphid	177 (429)	75.6

Identified non-vector species		6 (15)	2.6

Unidentified		10 (24)	4.3

	Sorted/Total*	234/567
*Actual numbers in sorted subsample (projected numbers in total collection)

Rolette, week ending 30 July
	Aphid species	# captured	% of total capture
PLRV/PVY vectors	green peach aphid
	potato aphid	2	9.1

PVY vectors	bird cherry-oat aphid	9	40.9
	corn leaf aphid
	English grain aphid
	greenbug
	sunflower aphid
	thistle aphid
	turnip aphid	6	27.3

Identified non-vector species		1	4.5

Unidentified		4	18.2

	Total	22

Walhalla, ND, week ending 29 July
	Aphid species	# captured	% of total capture
PLRV/PVY vectors	green peach aphid	5	5.7
	potato aphid	2	4.5

PVY vectors	bird cherry-oat aphid	3	3.4
	corn leaf aphid	5	5.7
	English grain aphid	1	1.1
	greenbug
	sunflower aphid	1	1.1
	thistle aphid	11	12.5
	turnip aphid	31	35.2

Identified non-vector species		9	10.2

Unidentified		18	20.5

	Total	88

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