Sweet Corn

European corn borer (ECB) adults have all but disappeared over the past week, and no map will appear in this edition.    Larval infestations are sparse now, as the last corn plantings to be exposed to ECB in the whorl now have entered the silk stage.

The highest nightly trap catches of ECB for the week ending 7/15/20 are as follows:

Fall armyworm (FAW) has declined, and larval infestations are no longer evident in the northern counties.  There are still low infestations in Cape May County, and moths are being captured there as well as near the Burlington/Camden County border.  This is the time of the summer when FAW can show up, resulting in significant injury to whorl and even seedling stage corn.  Injury from newly hatched larvae shows up as “window panes” or areas where leaf tissue has been eaten down the the lower epidermis (see photo at left).  This injury leads down into the whorl.  As larvae gain size, they begin to consume leaf tissue in its’ entirety, creating ragged holes and lots of droppings (see photo at right).  FAW can be tough to manage because it is resistant to synthetic pyrethroid insecticides (IRAC 3A) and because larvae are often covered by their own droppings, making contact with the insecticide more difficult.  Treat when 12% or more plants exhibit FAW injury alone, or in combination with ECB injury.

Corn earworm (CEW) moth captures remained steady at reasonably low levels in blacklight traps this past week.   Despite these lower counts,  silking corn continues to require protection from this pest.  Blacklight catches remain highest overall along the coast (see map at left).

The highest nightly trap catches of CEW in black light traps for the week ending 7/15/20 are as follows:

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Sweet Corn

European corn borer (ECB) moth catches have fallen to very low levels over the past week.   Remaining activity is highest in Gloucester and Camden counties (see ECB map at left).  Threshold (12%+) level larval infestations are declining now, as the last corn plantings to be exposed to ECB in the whorl now are entering the silk stage.  Larval infestations should decline sharply until the second flight appears.

The highest nightly trap catches of ECB for the week ending 7/08/20 are as follows:

Fall armyworm (FAW) larvae have appeared in low numbers in fields in Cape May County, as well as in Hunterdon and Morris counties.  This pest seems to have arrived last week some time, and has since subsided somewhat.  This is the time of the summer when FAW can show up, resulting in significant injury to whorl and even seedling stage corn.  Injury from newly hatched larvae shows up as “window panes” or areas where leaf tissue has been eaten down the the lower epidermis (see photo at left).  This injury leads down into the whorl.  As larvae gain size, they begin to consume leaf tissue in its’ entirety, creating ragged holes and lots of droppings (see photo at right).  FAW can be tough to manage because it is resistant to synthetic pyrethroid insecticides (IRAC 3A) and because larvae are often covered by their own droppings, making contact with the insecticide more difficult.  Treat when 12% or more plants exhibit FAW injury alone, or in combination with ECB injury.

Corn earworm (CEW) moth captures have declined in blacklight traps this past week.   Despite lower moth levels,  silking corn continues to require protection from this pest.  Blacklight catches remain highest overall along the coast (see map at left).

The highest nightly trap catches of CEW in black light traps for the week ending 7/08/20 are as follows:

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Sweet Corn

European corn borer (ECB) moth catches have remained steady at very low levels over the past week.   At this time, activity is highest in Gloucester and Camden counties (see ECB map at left).  Catches are widely dispersed.   Above threshold (12%) larval infestations continue into the northern counties.  Larval infestations should be expected to continue for another week or so.

The highest nightly trap catches of ECB for the week ending 7/01/20 are as follows:

Corn earworm (CEW) moth captures stayed largely unchanged in blacklight traps this past week.   This lingering population is somewhat heavier than normal for this time of year, and silking corn will need protection from this pest.  Blacklight catches were highest overall along the coast (see map at left).

The highest nightly trap catches of CEW in black light traps for the week ending 7/01/20 are as follows:

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Sweet Corn

European corn borer (ECB) moth catches have declined somewhat over the past week.   At this time, activity is highest in Gloucester County and along the Cape May/Cumberland bay shore (see ECB map at left).  Catches are widely dispersed.   Larval infestations above 20% continue into the northern counties this past week.  Larval infestations should be expected to continue for approximately another 2 weeks.

As always, 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 (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 6/24/20 are as follows:

Corn earworm (CEW) moth captures increased slightly in blacklight traps this past week.   As early plantings are now in the silk stage, they will need protection from this pest.  Blacklight catches sere highest overall along the coast (see map at left).

The highest nightly trap catches of CEW in black light traps for the week ending 6/24/20 are as follows:

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Sweet Corn

European corn borer (ECB) moth catches increased somewhat over the past week although higher numbers were recorded in a relatively low number of locations.  At this time, activity is highest in Gloucester and central  Morris counties (see ECB map at left).  Catches remain widely dispersed.   Larval infestations into the 30+% range were detected as far north as Morris County this past week.  As moth catches begin to fall, larval development and damage increase.  We expect that these infestation rates will continue to climb for the next 1-2 weeks in many parts of the state.

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 (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 6/17/20 are as follows:

Increased catches of corn earworm (CEW) moths were recorded this past week.   As early plantings proceed to full tassel and on to silk, they will need protection from this pest.  Blacklight catches (see map at left) were scattered, but higher in locations than the previous week.

The highest nightly trap catches of CEW in black light traps for the week ending 6/17/20 are as follows:

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Sweet Corn

European corn borer (ECB) moth catches have declined over the past week despite increasing temperatures.  At this time, activity is highest near the Hunterdon/Warren County border, although this is still a low level population (see ECB map at left).  The number of traps registering moderate catches remains low, and catches are widely dispersed.  Another week of trapping will clarify whether this decrease in activity signifies the end of the first flight.  A number of corn plantings are now in whorl through tassel stages and able to support ECB larvae.  Larval infestations as high as 12% were detected as far north as Hunterdon County this week.  As moth catches fall, larval development and damage increase.  We expect that with a few more warm days, these infestation rates will climb quickly in many parts of the state.

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 (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 6/10/20 are as follows:

Widely scattered, but slightly increased catches of corn earworm (CEW) occurred this past week.   As the earliest plantings (mainly in the south) proceed to full tassel and on to silk, even this low population can present a limited threat.

The highest nightly trap catches of CEW in black light traps for the week ending 6/10/20 are as follows:

[Read more…]