Sweet Corn

European corn borer (ECB) moth catches are very low in blacklight traps in the northern and central counties.  Feeding signs are largely absent from whorl and pre-tassel stage plantings.

The highest nightly trap catches of ECB for the week ending 7/03/24 are as follows:

The low level fall armyworm (FAW)  infestations we had found in some whorl stage corn in central NJ, have been treated and new infestations have not occurred.  It is possible that some infestations remain in unmonitored fields.  It is important to check  short whorl plantings at least weekly for the remainder of the season because early detection and treatment limit irreversible damage to plants.

Newly hatched FAW larvae cause holes and scratches on leaves that are similar to ECB feeding, except that they tend to be more concentrated and always lead down into the whorl  (see photo at left).  As the larvae grow, the feeding becomes more destructive, with large ragged holes and obvious droppings deposited in the whorl (see photo at right). 

We will provide updates on new FAW appearances and severity as reports come in.  FAW are resistant to synthetic pyrethroids.  Effective sprays should include IRAC grp. 5 (spinosyns) or IRAC grp. 28 (diamides).  The carbamate (IRAC grp. 1A) Lannate is also still effective.  Sufficient water should be used in the applications to allow the solution to penetrate the layer of droppings that may have formed above the caterpillar.

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Sweet Corn

European corn borer (ECB) moths have declined in blacklight traps in the northern and central counties, and feeding is also declining as previously infested plantings enter the silk stage and are treated.   Plantings now in whorl stage are showing little feeding.

The highest nightly trap catches of ECB for the week ending 6/26/24 are as follows:

Low level fall armyworm (FAW)  infestations have been detected in a few whorl stage plantings in central counties ranging from Princeton in Mercer County to Farmingdale in Monmouth County.  There are likely more of these infestations in central and southern NJ counties.  The appearance of very scattered clusters of infested plants points to a low number of moths arriving prior to the last weather front.  These individuals will have deposited eggs on small groups of plants, resulting in the feeding pattern we now see.  Many of these fields are below 2% plants infested.  It is possible, however, that some fields in the southern counties have higher infestation levels, so it’s important to check these short whorl plantings at least weekly.

Newly hatched FAW larvae cause holes and scratches on leaves that are similar to ECB feeding, except that they tend to be more concentrated and always lead down into the whorl  (see photo at left).  As the larvae grow, the feeding becomes more destructive, with large ragged holes and obvious droppings deposited in the whorl (see photo at right). 

We will provide updates on new FAW appearances and severity as reports come in.  FAW are resistant to synthetic pyrethroids.  Effective sprays should include IRAC grp. 5 (spinosyns) or IRAC grp. 28 (diamides).  The carbamate (IRAC grp. 1A) Lannate is also still effective.  Sufficient water should be used in the applications to allow the solution to penetrate the layer of droppings that may have formed above the caterpillar.

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Sweet Corn

European corn borer (ECB) moths continue to be captured in blacklight traps in the northern and central counties, although catches are occurring at fewer sites.  The highest feeding levels are in Somerset and southern Hunterdon Counties.   ECB injury is declining as infested plantings pass into the tassel stage and receive the first insecticide application.  Plantings now in whorl stage are showing little feeding.  While ECB has become something of a local phenomenon in NJ, growers should not assume that feeding is below economic levels in their area.  ECB infestations will be present for another 1-2 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 6/19/24 are as follows:

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