Thursday, June 9, 2016

Watch for Cereal Aphids in Winter and Spring Wheat / Small Grain Survey Maps for Minnesota and North Dakota



Cereal aphid Infestation levels in recent weeks 
illustrate the northward movement to HRSW 
from the earlier infestations of Winter Wheat in 
southern MN.
Field reports from Minnesota (MN) indicate that the cereal aphids reported in winter wheat in early May, many of which were treated at the time of herbicide/fungicide applications, are now moving to spring wheat in those southern areas of MN. Surveys are also detecting movement and colonization northward to central and northern HRSW areas of MN. In North Dakota and Minnesota, IPM Scouts are finding these increasing populations, so continue to scout fields for cereal aphid population buildups.

Small Grain Survey maps are now available on a weekly basis and can be accessed for viewing:
  • crop development
  • disease observations, both incidence (% infested plants) and severity (level of infection)
  • insect infestations

Links to the survey maps are at the top of the right column or can be found at:  


Recent rains last week can help reduce aphid populations by increasing the risk of infection by fungal pathogens that infect and kill aphids (see image to right). Fungal infected aphids do not move and appear bloated and fuzzy. 

The economic threshold is 85% incidence (infested stems) prior to the completion of heading. After heading, cereal aphids usually do not cause significant yield losses, but can reduce grain quality (protein and test weight) if populations are economic and plants are stressed from abiotic factors, such as drought. Normally, after heading stages, aphid populations fail to sustain themselves for long enough time to affect quality.