Pestwatch Reveals Sweet Corn Moth Pressure Starting

Corn earworm is already present throughout the state. European corn borer flights are high in Bradford Co, and significant in Bucks, Clinton, and Lancaster Counties.

This is Shelby Fleischer, from the Penn State Vegetable Extension Team, reporting from PestWatch on June 18, 2014.

Earworm, as in this picture, and corn borers, present risk to early season sweet corn

Corn earworm (CEW):

Moths are already present throughout the state: 18 of 21 sites reported captures, an additional 2 sites not on the chart also reported captures.  Sites in Clinton and Washington exceed a wide spray threshold, but this would only apply to silking corn.  If silking corn is present on your farm, it will strongly attract egg-laying females.  If silking corn is not present, CEW will lay its eggs on other flowering crops and weeds.  Mortality to the resulting eggs and larva can be very high due to both biocontrol and weather.  This early appearance of corn earworm does create the potential for a 2nd generation in PA later this summer.  Hopes of a delayed presence of CEW due to the cold winter do not appear to be working.

European corn borer (ECB):

Counts pheromone traps are very high in Bradford Co., and also exceeding thresholds in Bucks, Clinton, Lancaster, and Centre counties.  Scout fields for shothole and feeding damage to see if ECB have already moved into your fields.  If they have, a single spray at row tasel should be sufficient.  Bt-sweet corn will not be damaged by ECB.

Fall armyworms (FAW):

are being reported from several counties.  At this time of year, this is due to nontarget captures of a moth called Leucania phragmatidicola  (it does not have a common name).  More information about this nontarget is available on our Armyworm Pheromone capture factsheet

In summary, we already have corn earworm throughout the state, which can be a threat to silking corn.  If you have silking corn in Westmoreland or Clinton counties, wide spray intervals are warranted.  Corn borer trap counts are very high in Bradford Co., and also significant in Bucks, Clinton and Lancaster Counties.

Source : psu.edu