Sweet Corn

Low numbers of European corn borer (ECB) moth activity has declined to very low levels in areas where blacklight traps are operating in the northern and central counties.  Feeding in whorl and pre-tassel stage corn has increased only slightly over the past week, with many plantings exhibiting no ECB injury at all.    While ECB has become something of a local phenomenon in NJ, growers should not assume that feeding is below economic levels in their area.

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 6/28/23 are as follows:

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Sweet Corn

Low numbers of European corn borer (ECB) moths remain active in areas where blacklight traps are operating in the northern and central counties, although feeding in whorl and pre-tassel stage corn is low and sporadic in occurrence.  The highest feeding levels are in southern Hunterdon and Monmouth counties.   ECB injury around 20% of plants infested has been found in those areas recently.  While ECB has become something of a local phenomenon in NJ, growers should not assume that feeding is below economic levels in their area.   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 6/21/23 are as follows:

[Read more…]