Aphid numbers continue to climb this week with over 200 more aphid vectors collected this week as compared to last week. Twelve sites recorded their highest numbers of the season. We are seeing soybean aphids at most sites and high numbers of them at Ada, Perham, Forest River, and Sabin. Green peach aphid was recovered this week from Ada, Forest River, Hoople, Langdon, Perham, Staples, Stephen, and Walhalla.
Lots of potential for virus transmission out there right now. Make sure you are making the right management decisions to keep your potatoes disease-free!
Keep Scouting! 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.