Nineteen sites reporting this week. European corn borer numbers are starting to increase again with eight sites reporting ECB-E and four sites reporting ECB-Z. Two of the six sites reporting corn earworm (CEW) were over threshold, indicating a need for a spray, please see the chart at the bottom of this page to determine the correct spray interval for your field. Fall armyworm (FAW) catches were up this week as well, with ten sites reporting trap catches. The site in Erie County caught 77 total FAW. Western bean cutworm (WBC) was also up this week with fourteen sites reporting trap catches, one as high as 96 moths.

Michigan State University recommends scouting for WBC egg masses when cumulative trap catch numbers reach 100 moth/trap for field corn. Whether this guideline also pertains to sweet corn is not known. Therefore it is recommended that all fields that are in the whorl or early tassel stage be scouted for egg masses with a 4% threshold for processing sweet corn and a 1% threshold for fresh market sweet corn. I scouted one field this week that had a cumulative trap catch of only 5 WBC moths and found one egg mass. WBC will usually lay eggs on the upper side of the top 1-3 leaves of pre-tassel corn, close to the leaf base. After tasseling has finished WBC seek out younger corn or dry beans. To scout for egg masses check the top 3 leaves of ten corn plants in ten locations throughout the field. The eggs are easy to observe if you view the leaf while holding it towards the sun. The egg mass will appear as a distinct shadow (see photo).

It takes between 5-7 days for eggs to hatch. It is critical that sprays are timed before the larvae have a chance to enter the ear. The egg mass will become purple in color approximately 24 hours before egg hatch (see photo).

Location ECB-E ECB-Z CEW FAW WBC Total WBC
to date
DD
to date
Avoca (Steuben Co.) 0 0 0 0 1 1 1265
Avon (Livingston Co.) 0 0 0 9 6 6 1452
Baldwinsville (Onondaga Co.) 2 0 0 1 11 11 1470
Batavia (Genesee Co.) NA NA NA NA NA 0 1142
Bellona (Yates Co.) 2 2 0 4 2 2 1512
Eden (Erie Co.) 5 0 0 77 96 96 1361
Farmington (Ontario Co.) NA NA NA NA NA 0 1386
Hamlin (Monroe Co.) 2 1 1 0 0 0 1360
Kennedy (Chautauqua Co.) 0 0 0 4 19 24 1159
King Ferry (Cayuga Co.) 5 0 0 3 1 1 1425
Kirkville (Madison Co.) 22 0 1 1 9 9 1532
LeRoy (Genesee Co.) 0 2 2 0 0 0 1260
Lockport (Niagra Co.) 6 0 0 NA 0 0 1282
Oswego (Oswego Co.) 0 0 1 3 2 5 1342
Owego (Tioga Co.) 0 0 0 0 0 0 1292
Pavilion (Genesee Co.) NA NA NA NA NA 3 1260
Penn Yan (Yates Co.) 0 0 0 0 1 1 1469
Plessis (Jefferson Co.) 1 0 1 0 13 15 1274
Preble (Cortland Co.) 0 0 0 7 3 3 1417
Seneca Castle (Ontario Co.) 0 0 0 0 1 2 1395
Sherwood (Cayuga Co.) NA NA NA NA NA NA 1425
Spencerport (Monroe Co.) 0 0 2 1 0 0 1452
Waterport (Orleans Co.) NA NA NA NA NA 0 1360
Williamson (Wayne Co.) 0 1 0 0 10 11 1296
ECB – European Corn Borer
CEW – Corn Earworm
FAW – Fall Armyworm
WBC – Western Bean Cutworm
NA – not available
DD – Degree Day (modified base 50F) accumulation
trap catches for the week of 7.15.14-7.22.14

 

Below is a graph of the average trap catches to date. The first flight of ECB happened in mid June and we are now seeing the beginning of the second flight of ECB as well as the beginning of WBC and FAW flights.

Average trap catch to date.

Average trap catch to date.

cewtable