Here's the catch for the Trapping Period ending Aug 15
Green
peach aphid (one of the most important and most effective vectors of
PVY) was detected in 4 trap locations; the Forest River ND, Lake of the Woods MN, Sabin MN
and Staples MN sites. If
seed potato vines have not yet been killed at these sites, it should be noted
that green peach is the most efficient vector of PVY. For the second week soybean aphids were recovered at 1
location but
their presence and flight remains low. Southern MN is reporting
increased soybean aphid populations but it is not clear of these
populations will disperse to northern areas.
There were significant flights of both bird cherry oat and buckthorn aphids in several locations. While neither is the most efficient vector of virus disease, the
presence of any PVY vector is cause to scout and manage accordingly. At most sites there was a slight
decrease in the numbers of vectors recovered from traps with the exception of
Lake of the Woods, which saw a significant increase. It should be noted, however, that Lake of the
Woods trap contents from 8/08 and 8/15 had to be combined, and so this increase
reflects 2 weeks of sample effort.
The
number of non-vector aphid
species recovered in most traps was down this week, indicating overall aphid movement may have been suppressed by colder temperatures.
As always - to scout for aphids in
potatoes, select leaves from the lower to mid canopy. Lower, older leaves
will have more established colonies and aphids prefer the balance of nutrients
found here; aphids are rarely found on leaves in the upper canopy. Avoid leaves
on the ground or in contact with the soil. In seed potatoes there is only a
threshold for PLRV (10 aphids/100 leaves), reactive application of insecticides
an effective control for PVY. However, the use of feeding suppressing
insecticides, such as Fulfill (Syngenta Crop Protection) or Beleaf (FMC
Corp.) and refined crop oils, such as Aphoil and JMS Stylet Oil, at or prior to
field colonization by aphids may reduce the transmission of PVY within fields.
In table stock potatoes, a treatment threshold of 30 aphids /100 leaves should
deter yield loss due to aphid feeding.
Aphid
Species Captured (per suction trap 8/08/2012 – 8/15/2012)
|
|||||||||
Cando
ND
|
Forest
River ND
|
Linton
ND
|
Lake
of the Woods MN
|
Gully
MN
|
Stephen
MN
|
Sabin
MN
|
Perham
MN
|
Staples
MN
|
|
Green peach aphid (Myzus persicae)
|
1
|
2
|
1
|
1
|
|||||
Soybean aphid
(Aphid glycines)
|
2
|
||||||||
OTHER
PVY VECTORS
|
|||||||||
Bird cherry oat aphid (Rhopalosiphum padi)
|
32
|
2
|
1
|
9
|
3
|
||||
Corn leaf aphid (Rhopalosiphum maidis)
|
1
|
4
|
1
|
1
|
|||||
English grain aphid (Sitobion avenae)
|
4
|
1
|
|||||||
Green bug (Schizaphis graminum)
|
|||||||||
Potato aphid (Macrosiphum euphorbiae)
|
2
|
1
|
1
|
||||||
Sunflower aphid (Aphis helianthi)
|
|||||||||
Thistle aphid (Lipaphis
erysimi)
|
1
|
1
|
|||||||
Turnip aphid (Brevicoryne brassicae)
|
|||||||||
Cotton/melon aphid (Aphis gossypii)
|
|||||||||
Pea aphid (Acyrthosiphon pisum)
|
|||||||||
Cowpea aphid (Aphis craccivora)
|
1
|
2
|
1
|
1
|
|||||
black bean aphid (Aphis fabae)
|
|||||||||
Buckthorn aphid (Aphis nasturii)
|
24
|
1
|
2
|
2
|
|||||
Identified
non-vectored species
|
1
|
1
|
1
|
6
|
23
|
1
|
1
|
||
Unidentified
|
2
|
||||||||
Total # captured
|
4
|
2
|
2
|
62
|
7
|
12
|
38
|
8
|
7
|
Total Verctors
|
4
|
1
|
1
|
61
|
7
|
6
|
15
|
7
|
6
|
