Sweet Corn

Low numbers of European corn borer (ECB) moths continue to be captured throughout the state.  The highest adult activity is currently from Gloucester through Burlington counties (see map at right).  Whorl corn is the primary target for egg laying, and injury well over the 12% threshold has been found in Hunterdon County this week.  Feeding percentages in many areas have been relatively low, but this pest still poses a threat to plantings now approaching full tassel.  It is typical for feeding percentages to rise as the moth catch declines.  We expect feeding to increase for the next 1-2 weeks before peaking.

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 6/08/22 are as follows:

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Sweet Corn

Low numbers of European corn borer (ECB) moths have been captured in parts of the state.  Overall, this flight has been weak, but consistently warmer weather may result in somewhat higher numbers over the next week.  The highest adult activity is currently in Burlington and Gloucester counties, although even there it is low.  Whorl corn is the primary target for egg laying, and injury as high as 4% of plants infested has been found in northern Burlington County this week.  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 5/31/22 are as follows:

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Sweet Corn

European corn borer (ECB) moths are now being captured in parts of the state.  Numbers are low, and no map will appear in this edition.  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 plants are not large enough to support ECB larvae.  We expect to encounter some level of feeding over the next 2 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 5/25/22 are as follows:

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Sweet Corn

IPM Program personnel are finished deploying black light traps and nearing completion of the corn earworm (CEW) pheromone trap network in New Jersey.    Limited collections from traps thus far have captured one corn earworm (CEW) from Chester in Morris County.  We anticipate only limited CEW and  European corn borer (ECB) moths for the near term, and as numbers increase, look for population maps of ECB, CEW, brown marmorated stink bug (BMSB).  The resulting full-state maps will include interpretive information.

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