Trap Catches Sept 06 - Sept 13, 2024.

As the season winds down and only 3 sites reporting this week, aphid vector numbers again decreased. The average number of vector aphid species recovered per location is less than half that of last week, and the average PVY Vector Risk Index values at each location reflect that decrease.  Our average regional numbers are close to the 2012-2023 average (see chart below).  

Most locations have already vine killed and movement from other cropping systems is also declining significantly.  Even soybean aphids were low.  Good news after late season flights.

For those few locations that have not yet vine killed, remember, virus transmission remains a concern as long as plant material is green and circulating. 

Bottom line - this will likely be the last week of trap contents coming in.  Our regional populations this season closely matched the 2013-2023 average for both aphid vector numbers and PVY Vector Risk Index values in pattern and magnitude.

The top chart shows the average regional aphid vector captures/trap and PVY Vector Risk Index to Sept 13, 2024.  The lower graph shows the regional average aphid vector captures/trap and PVY Vector Risk Index averaged from 2012 to 2023.  The dates are expressed in ISO Week numbers (a standardized method of presenting dates across years).    

Click on any image below for full-scale version.

Cumulative PVY Vector Risk Index to 9/13/2024

Cumulative PVY Vector Risk Index to 9/08/2023 for Comparison

Aphid Species Capture and PVY Vector Risk Index for the week ending 9/13/2024

Cumulative Aphid Species Capture and PVY Vector Risk Index to 9/13/24

 Trap Catches Aug 31 - Sept 06, 2024.

With 5 trap locations reporting, the average number of vector aphid species recovered per location has again significantly declined this week, as has the average PVY Vector Risk Index values at each location.  The early September drop in aphid numbers agrees closely with the 2012-2023 average of regional aphid population dynamics (see chart).  

While numbers are lower, important vector species remain in the trapping area.  Both Becker, MN and Crystal ND traps recorded green peach aphids this week.  Soybean aphids are lower but still widely distributed (both MN and ND sites reported this species). Other aphid species, including non-vectors, have decreased.  

Heavy aphid infestations in central MN commercial fields have continued, becoming wide spread in some fields.  Thee higher temperatures this week may continue to drive reproduction somewhat but the cool nights will ameliorate that increase.  Many fields have been vine killed and so this is not problematic.  For those that are continuing to grow and populations are difficult to control, several aphid-targeted insecticides may be effective; Transform (Cortev; sulfoxaflor), Sivanto Prime (Bayer Cropscience; flupyradifurone), or Sefina (BASF; afidopyropen) are all effective aphicides and have performed well in field trials.

For those locations that have not yet vine killed, virus transmission remains a concern as long as plant material is green and circulating. 

Bottom line - aphid populations and PVY Vector Risk significantly decreased again over the last week. Any field that is not yet vine killed remains susceptible to potential virus transmission...  

The top chart shows the average regional aphid vector captures/trap and PVY Vector Risk Index to Sept 06, 2024.  The lower graph shows the regional average aphid vector captures/trap and PVY Vector Risk Index averaged from 2012 to 2023.  The dates are expressed in ISO Week numbers (a standardized method of presenting dates across years).    

Click on any image below for full-scale version.

Cumulative PVY Vector Risk Index to 9/06/2024

Cumulative PVY Vector Risk Index to 9/08/2023 for Comparison

Aphid Species Capture and PVY Vector Risk Index for the week ending 9/06/2024

Cumulative Aphid Species Capture and PVY Vector Risk Index to 9/06/24