| Week 1, 1998. Aphid trapping was begun the last week of June.
The dots (actually circles) on the map represent sample locations. In all maps, the
area of the circle is in proportion to numbers of aphids captured per trap. During
the first week of trapping no green peach aphids were captured. To view any image in
greater detail click on image. |
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| Week 2, 1998. Trapping network was still under construction. Traps were
operating only at Little Falls, Hollandale, Morris, and Lamberton. A single green peach
aphid was captured at Morris, which was most likely a spring migrant arriving from its
overwintering site. |
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| Week 3, 1998. Trapping network has been established except the site at
Karlstad. A single green peach aphid was captured at Morris, and 10 green peach aphid was
captured at Climax. |
|
| Week 4, 1998. Large colonies of green
peach aphids containing all life stages and forms (winged and wingless) has been found in
a canola field near Crookston, MN. Green peach aphids were captured at Waseca (4), Climax
(1), and Karlstad (1). |
|
| Week 5, 1998. Sporadic green peach aphid captures occurred across the
trapping network, Little Falls (1), Hoople (1), Cando (1), and Rolette (1). Green peach
aphid colonization of seed potato fields had begun. The numbers of wingless green peach
aphids found at Hoople and a field near Grafton had exceeded treatment threshold. |
|
| Week 6, 1998. Green peach aphids were captured across the trapping network
indicating that summer migration of green peach aphid is now occurring throughout the Red
River Valley. Green peach aphids were captured at Lamberton (1), Little Falls (1), Climax
(2), Hoople (12), Cando (8), and Rolette (1). |
|
| Week 7, 1998. An increase of green peach aphid captures has been observed
across the trapping network indicating the increased flight activity of summer migrants.
Inspectors of the Minnesota Department of Agriculture have also reported an increase in
seed potato fields colonized by green peach aphids. Green peach aphids were captured at
Hollandale (2), Waseca (3), Lamberton (2), Morris (2), Baker (1), Climax (5), Karlstad
(14), Hoople (31), Cando (12), and Rolette (46). |
|
| Week 8, 1998. Green peach aphids were captured across the trapping network
indicating that summer migrants of green peach aphid are now occurring throughout the
State. Green peach aphids were captured at Hollandale (2), Lamberton (2), Morris (12),
Little Falls (3), Baker (3), Climax (16), Karlstad (10), Williams (2), Hoople (21), Cando
(13), and Rolette (22). |
|
| Week 9, 1998. Green peach aphid capture continued to increase and
colonization of potato fields were a common occurrence across the Valley. In potato fields
where aphid management did not follow recommendations, result of large-scale aphid
colonization is especially striking. In these fields severe aphid pressure did not only
caused aphid holes but also whole fields were killed prematurely by aphids. Green peach
aphids were captured at Waseca (2), Lamberton (3), Morris (1), Little Falls (1), Baker
(3), Climax (57), Karlstad (25), Williams (6), Hoople (67), Cando (2), and Rolette (9). |
|
| Week 10, 1998. Green peach aphid flight activity was generally similar to
that of previous week. Aphid holes had been observed on seed potato fields. Green peach
aphids were captured at Morris (4), Little Falls (1), Climax (71), Karlstad (13), Williams
(2), Hoople (26), and Rolette (1). |
|
| Week 11, 1998. Green peach aphids flight activity decreased across the
State. Green peach aphids were captured at Little Falls (1), Climax (4), Karlstad (4),
Williams (1), Hoople (6). There were no traps at Hollandale. |
|
| Week 12, 1998. Green peach aphids were captured only at Hoople (5). There
were no traps at Rolette. |
|
| Week 13, 1998. No green peach aphid capture. There were no traps at
Lamberton, and Little Falls. |
|
| Week 14, 1998. Green peach aphids were captured at Climax (1), and
Williams (1). There were no traps at Morris. |
|
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| Week 1, 1998. Few PVY vectors
bird-cherry oat aphids and English grain aphids were captured at Little Falls and
Hollandale. |
 |
| Week 2, 1998. PVY species capture
increased in the southern sites. |
 |
| Week 3, 1998. Increased flight of PVY vectors with the largest aphid
capture at Climax. Sunflower and grain fields in close proximity to the Climax trapping
site are most likely responsible for the large numbers of aphid caught at Climax. |
|
| Week 4, 1998. PVY vector capture
almost doubled in Climax and Hoople. Substantial numbers were also caught at Karlstad.
However, the southernmost site, Baker and the northernmost sites Williams, Cando and
Hoople had lower captures than the central Red River Valley. |
|
| Week 5, 1998. There was a general
increase in PVY capture across the Red River Valley. This increase corresponds to the
buildup of aphids in maturing small grain fields, weeds and other crops. |
|
| Week 6, 1998. There was a rapid increase of PVY vector capture this week.
Sunflower aphids were abundant at all sites of the Red River Valley and over 70% of aphids
captured were sunflower aphids at Climax and Hoople where the highest capture occurred. |
|
| Week 7, 1998. Aphid captures begun to decline at the southern sites while
they peaked at the northern sites. Sunflower aphids were the dominant species at all
sites. |
|
| Week 8, 1998. Flight activity of PVY vector species declined across the
Red River Valley. |
|
| Week 9, 1998. Similar flight activity of PVY species to the previous week. |
|
| Week 10, 1998. Rapid declined flight activity of PVY vector species
signaling the end of PVY vector flight activity. |
|
| Week 11, 1998. Only sporadic capture of PVY vector species across the
trapping network. |
|
| Week 12, 1998. Only sporadic capture of PVY vector species across the
trapping network. |
|
| Week 12, 1998. Only sporadic capture of PVY vector species across the
trapping network. |
|
| Week 12, 1998. Only sporadic capture of PVY vector species across the
trapping network. |
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