Fall Armyworm Moth Flight Numbers Begin to Rise Again.

Doug Johnson, Extension Entomologist


The number of reports of fall armyworm (FAW) infested fields has slacked off for the present. Unfortunately, I do not think this problem is over for the year. I believe our IPM pheromone- baited traps are supporting this notion with an up-tick in captures this week.

Notice up-tick in green line.

If we look at the FAW moth captures for the year so far (Figure 1.), we can see three telltale signs. All three of these may be found in the relationship of the 2012 flight (Green line) to the 2007 outbreak population (Red line) and the rolling five-year average (Blue line). The 2012 flight of moths is: 1. much earlier, 2. much larger, and 3. appears to be starting to climb, indicating a second moth flight. None of these is absolutely definitive that we will experience a second economically important worm population, but they certainly indicate that we should be watching for one. That certainly seems to be the opinion of my colleagues in states to the south of us, and they experience FAW more often than do we.

We will not know until we see the moth flight numbers for the trap week ending Thursday, Sept 13th, or perhaps even the trap week ending Sept. 20th whether or not we have a second and threatening population. To my knowledge, there is no precedence for this in KY. Certainly we have seen FAW linger until frost, but we have not seen them do this in widespread large numbers.

When viewing these graphs, please remember that you are looking at moth capture. Moths are not the damaging stage in this insect. Moths (adults) are simply responsible for reproduction, dispersal, and egg lay. The resulting worms (damaging stage) will appear after a 1-2 week delay from the moth flight.

See the article: The Affect of Insect on Wheat Planting Decisions, in Kentucky Pest News at:
http://www.ca.uky.edu/agcollege/plantpathology/extension/kpnindex.htm
 for a look at the possible impact of insects, including FAW, and mites on the 2012 wheat crop.

Also see the Wheat Science News Letter at:

http://www2.ca.uky.edu/wheatscience-files/Sept_6_2012_Wheat_Newsletter.pdf

for Insect & other pest considerations and agronomic information related to the 2012 planting season.