Aphids continue to fly in the Red River Valley and beyond and vector captures increased in several locations this week. Catches in Hoople and Forest River (ND) and Stephen, Crookston, Erskine and Perham (MN) all recovered aphid vectors. Green peach aphids were recovered in the Hoople trap and soybean aphids were recovered in the Linton locations, Forest River, Stephen, Crookston, Lake of the Woods, Staples and Perham traps. Cereal aphids continued to be recovered in numbers from most locations. Additionally, there have been reports of potato aphids in flax in Roseau, MN. We continue to have an aphid summer in MN and ND.
So, vector pressure continues - if you have not yet vine killed, then...
Scouting & treating 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 standard broad-spectrum insecticides are not an effective control for PVY (by the time the aphid has been exposed and dies, it can have moved PVY inoculum into and, more importantly, within the field.
- 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
* the posts will be updated again Aug 16. If needed, contact the lab at 218.281.8633 and ask for Ian or Nate...
Weekly Trap Catch (click on the image for larger version)
Cumulative Seasonal Catch (click on the image for larger version)