Pestwatch Report

This week all sites reported corn earworm catches with counts trending strongly upwards across the southern portion of the state. Most locations across the southern region from Pittsburg through Belleville and east through Lancaster and Montgomery Counties are in a 4 day spray interval. Counties to the North have reported few trap catches and can maintain a longer spray interval. It is important to note that when average temperatures exceed 80 degrees, you should shorten your spray interval by one day because silks grow much more quickly leaving larger unprotected areas and corn earworm eggs also hatch more quickly. If irrigation or rain wash off the spray within 24 h after application, repeat treatment as soon as the foliage dries.

I expect trap catches to continue in this upward trend through August and Early September as we have both local moths generations emerging as well as storms carrying migrating moths up from the south. These population that migrate from the south tend to carry particularly high resistance to pyrethroid insecticides. David Owens at University of Delaware recommends paring a pyrethroid with a methomyl spray followed by either a spray containing a diamide or Intrepid Edge + a pyrethroid.

I would love to hear about how your sweet corn harvests are progressing whether you feel you have been getting good control or if you have experienced any challenges. Please send me an email at heathergrab@psu.edu or leave a message at 717-364-6198.

The maps and graphics below will update in real time as reports come in across the state.

Weekly Corn Earworm Trap Catches

Click on a site in the map below to see historical trap catch data for a site relative to catches during the current season. Spray intervals are indicated by the color of the point based on weekly trap catch.

Average Weekly Corn Earworm Catch

The table below shows trap catches for the two most recent weeks. If no data exist for that week, the cell is blank.

Statewide Corn Earworm Trends

The figure below shows the weekly average trap catch for the current year (bold line) up to the most recent period, as well as the weekly trends for past years.

Weekly Fall Armyworm Trap Catches

Click on a site in the map below to see historical trap catch data for a site relative to catches during the current season. Spray intervals are indicated by the color of the point based on weekly trap catch.

Average Weekly Fall Armyworm Catch

The table below shows trap catches for the two most recent weeks. If no data exist for that week, the cell is blank.

Statewide Fall Armyworm Trends

The figure below shows the weekly average trap catch for the current year (bold line) up to the most recent period, as well as the weekly trends for past years.