Friday, June 20, 2014

Welcome to the 3rd season of Aphid Alert II

Welcome to the 3rd season of Aphid Alert II – assessing the weekly distribution of aphid vectors of Potato Virus Y in Minnesota and North Dakota.  We added several sites this year and hope to expand to more than 20 sites for the season.

The first week’s catch is in and identified.

As in the past two years, we’ll be supplying the data in both tabular and graphic formats.  This season has had a slow start, with late planting.  There have been a couple of wind events that could possibly bring aphid vectors into the region from the south.  Keep an eye on fields!

Scouting 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.
 - The use of feeding suppressing insecticides, such as pymetrozine (Fulfill®) or flonicamid (Beleaf®) 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. Some other insecticides, such as clothianidin (Belay®), imidacloprid (Admire Pro® or Provado®), and spirotetramat (Movento®), have also been demonstrated to reduce the transmission of PVY. 
- In table stock potatoes, a treatment threshold of 30 aphids /100 leaves should deter yield loss due to aphid feeding.