Sweet Corn

Due to continued cold night temperatures, European corn borer (ECB) moth captures have been extremely low in northern and central county light traps.  Thus far this flight has been weak, and no feeding has been detected on whorl and pre-tassel stage sweet corn as far south as northern Burlington County.  An increase in nighttime temperatures (even temporarily) may result in somewhat higher numbers over the next week.   Whorl corn is the primary target for egg laying.  If the first flight is late rather than nonexistent, this sometimes results in heavier infestations on 2nd and 3rd plantings than on the first.  Feeding levels could be somewhat higher in the southern counties, and should rise over the next 3 weeks.

Look for the characteristic “shot-hole” type of feeding (photo below at right) and consider treating when infested plants exceed 12% in a 50 plant sample.  As plantings proceed to the pre-tassel stage, ECB larvae may be found in emerging tassels (see photo at left).  It is a good idea to treat individual plantings as they move into the full tassel/first silk stage one time.  This eliminates any ECB larvae that have emerged with the tassels as they begin to move down the stalk to re-enter near developing ears.

Useful insecticides for this particular application include synthetic pyrethroids (IRAC Grp 3), spinosyns (including OMRI approved Entrust) IRAC Grp 5), and diamides such as Coragen or Vantacor (IRAC Grp 28) or materials such as Besiege which include the active ingredient in Coragen.  Synthetic pyrethroids alone should NOT be used for corn earworm (CEW) protection on silking corn.  Control with these materials is very inconsistent.

The highest nightly trap catches of ECB for the week ending 5/30/23 are as follows:

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Sweet Corn

Scattered European corn borer (ECB) moths are now being captured in central and northern counties, and this insect is certainly active in southern parts of the state.  Numbers are quite low.  It remains to be seen whether this first flight will amount to much, but recent years’ catches give no reason to suspect that a large population will develop.   Whorl corn is the primary target for egg laying, but as yet, scouts have reported no signs of feeding injury.  In northern and central counties, corn plantings that were started on/under plastic are now reaching a size that will support ECB larvae.  We expect to encounter some level of feeding over the next 2 weeks, although the majority of plantings have not required insecticide treatments for ECB prior to full tassel in the past several years.

Look for the characteristic “shot-hole” type of feeding (photo below at right) and consider treating when infested plants exceed 12% in a 50 plant sample.  As plantings proceed to the pre-tassel stage, ECB larvae may be found in emerging tassels (see photo at left).  It is a good idea to treat individual plantings as they move into the full tassel/first silk stage one time.  This eliminates any ECB larvae that have emerged with the tassels as they begin to move down the stalk to re-enter near developing ears.

Useful insecticides for this particular application include synthetic pyrethroids (IRAC Grp 3), spinosyns (including OMRI approved Entrust) IRAC Grp 5), and diamides such as Coragen or Vantacor (IRAC Grp 28) or materials such as Besiege which include the active ingredient in Coragen.  Synthetic pyrethroids alone should NOT be used for corn earworm (CEW) protection on silking corn.  Control with these materials is very inconsistent.

The highest nightly trap catches* of ECB for the week ending 5/24/23 are as follows:

*  No blacklight traps are in operation south of the Columbus (Burlington Co.) area this season.

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Sweet Corn

IPM Program personnel are finished deploying black light traps in central and northern New Jersey and with help from South Jersey grower cooperators, nearing completion of a corn earworm (CEW) pheromone trap network in the state.    Limited collections from traps thus far have captured a small number of European corn borer (ECB) moths in blacklight traps as far north as Hunterdon County.  We anticipate only limited CEW and  ECB moths for the near term, and as numbers increase, look for updates on ECB, CEW and  brown marmorated stink bug (BMSB) catches, including interpretive information.

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Sweet Corn

There will be significant changes to insect trapping efforts in the Vegetable IPM Program for this season.  At present, personnel are deploying black light and corn earworm (CEW) pheromone trap networks in central and northern New Jersey counties.  In areas from central Burlington County southward, grower cooperators have been provided with CEW pheromone traps and will be monitoring these traps on their own properties and reporting catch data to IPM personnel.  This is an effort to maintain a statewide reporting program for the most significant economic pest of sweet corn despite a shortage of professional staff this year.  The IPM program thanks these growers in the southern counties for their assistance in maintaining this necessary service.

Black light trap derived maps for European corn borer (ECB), CEW and brown marmorated stink bug (BMSB) will not appear in the Plant and Pest Advisory, as there is no longer a statewide blacklight trap network.  Data from existing black lights in the central and northern counties will appear in table format, with associated information on the relevance of the populations.  Provided that  data from the southern CEW pheromone traps is available on a regular basis, maps will be generated for this pest/trap type.   Limited collections from traps thus far have not contained any target pests.

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