Fall armyworm Resistant to B.t. Corn found in North Carolina: is your field next?

Doug Johnson, Extension Entomologist, University of Kentucky.

  Mr. Cam Kenimer, who runs our corn variety trials, sent me a link to an interesting article “Armyworms develop resistance to Bt corn.” The article which is actually about fall armyworm (FAW) reports that this pest carries a gene that makes it resistant to the B.t. trait Cry1F. This trait

Fall Armyworm Moth Captures Rebounding

Doug Johnson, Extension Entomologist, University of Kentucky

 Capture of fall armyworm moths (FAW) in the UK- IPM traps at the UK-REC in Princeton, KY have increased for the last two weeks. These captures are not as great as those from the known outbreaks of 2007 and 2012. Nevertheless, the current capture level is greater than the rolling five year average,

Got Fall Armyworm? Want Some More!!!

Doug Johnson, Extension Entomologist, University of Kentucky
Patty Lucas, Extension IPM Specialist, University of Kentucky

Fig.1 FAW moth capture in UK-IPM trap in Princeton, KY

For the past week or so we have been dealing with large populations of fall armyworm (FAW) caterpillars. These hungry little pests have devoured alfalfa, forage and lawn grasses while munching around the edges of soybean fields. I am sorry to inform you that while this problem is decreasing it may also reoccur.

The caterpillars that have thus far caused our damage are probably the result of an increase in FAW moths during the last week of July. You must remember that FAW has been trickling into KY for several months and is a normal part of the pest pressure in August and September, particularly in the western 1/3 of the state. You can see this “pulse” in Figure 1. Also note that this graph is updated every week and can be viewed on the IPM web pages at:

http://www.uky.edu/Ag/IPMPrinceton/counts/fall/fawgraph.htm

Something is Definitely Up with Fall Armyworm!!

Doug Johnson, Extension Entomologist, University of Kentucky

Something is most definitely up with armyworm (Mythimna unipuncta), fall armyworm (Spodoptera frugiperda) or both. I have received information from six counties in less than a week indicating the

Big Jump in Fall Armyworm Moth Capture

Doug Johnson, Extension Entomologist, University of Kentucky

The trap week of July 17-24 showed a large increase in fall armyworm (FAW) moths captured in the western UK-IPM traps. The capture increasing from virtually none to 155/trap-week, is a pretty major change and worth noting.

Could Fall Armyworm Be A Threat Now??

Doug Johnson, Extension Entomologist, University of Kentucky

It seems completely ridiculous to me to be talking about fall armyworm (FAW) at this time of year in Kentucky.  So far we have not detected this insect in our UK-IPM pheromone baited traps at Princeton or Lexington and I have not heard of any detections in TN. Unfortunately, Arkansas is reporting an “outbreak” of this insect, and that gives me a little pause. In most years I would not expect to detect this insect until mid or late July and with the exception of very late planted corn in the purchase region, I would not expect it as a problem until August.

Insect Considerations for Wheat Planting Decisions

Doug Johnson, Extension Entomologist

As I travel around the countryside, I see plenty of emerging corn in fields that will likely be planted in wheat. This “Green Bridge” could lead to problems with certain insects important to wheat Production. The insect pests we need to consider have not changed from previous years, but their relative importance may have changed from last year. Fall armyworm (FAW), Hessian Fly (HF), cereal aphid complex (CAC), and wheat curl mite (WCM) are annual threats. In most years, only the CAC is of major concern. In 2012 the FAW was a considerable problem in west Kentucky, not only in wheat,but also in many forage grasses.

Fall Armyworm- Follow-up on the Fall 2012 Infestation.

Doug Johnson, Extension Entomologist and Patty Lucas, IPM Specialist

Fall armyworm moths.

We know a number of you had to deal with the large infestation of fall armyworm we saw this past September and October. Infestations were reported in grass hay, & pasture, newly established or renovated forage grasses, wheat and rye cover crops, as well as in late maturing soybean and early planted wheat for grain. This was an unusual event, perhaps the largest population of FAW in recent memory.

We would like to gauge the spread and impact of this pest in Kentucky. To aid us in this we have prepared a short survey on the Survey Monkey web site. This is a short survey and will not take you more than a few minutes to complete. We would appreciate it very much if you would provide us with your experience. You can reach the site at:

https://www.surveymonkey.com/s/VCGX5QL

This may not be a clickable link in the blog. If you cannot click on the address then please copy and paste  the address into your browser.

No information that will identify you will be collected by the site. There is one location in the survey where you may leave an email address to follow up if you so choose. Those addresses will be held in strict confidence. They will NOT be shared with anyone else, and will be stored offline.

We thank you in advance for taking just a few minutes to help us understand the impact, and distribution this insect had in 2012.



Fall Armyworm Moth Flight Up-tick…. But why?

Doug Johnson, Extension Entomologist

After a drop last week to 487 moths/trap-week from the peak capture of 675 moths/trap-week, capture of fall armyworm (FAW) moths in the UK-IPM pheromone baited trap has increased  to 605 moths/trap-week (See Figure 2.). This indicates a continued and elevated risk of infestation by this pest for the next several weeks. This up-tick in moths captured does not indicate another generation. It is more likely that the cool weather in the previous week reduced the number of moths flying and the warm up has done just the opposite. If this is the case, then last week’s moth capture should have been a bit larger and this week’s a bit lower, making the curve appear a bit more normal.

Figure 2. 2012 FAW Capture.

 This spiky appearance to the graph is just due to a small number of data points and a wide span of time (a week) between data points. What is most important is the fact that there are still a great many moths flying and females will still be laying eggs for several more weeks unless there is a drastic change in temperatures. Caterpillars resulting from the egg lay of the current moth flight have already begun to appear.  I expect that egg lay resulting from the moths represented by this week’s data point will continue into the first week of October. Caterpillars resulting from the current egg lay could be active through the entire month of October. This is, of course, completely dependent upon temperature.

We would normally expect for the threat from FAW to end on or about the first killing frost. Certainly we have eggs and caterpillars, in various stages of growth, currently in the environment that can last past the average first killing frost date. This does not even account for the moths that are currently flying, mating and laying eggs.

Thus, small grass crops will remain at risk to infestation by FAW until the weather changes enough to stop the cycle.  This usually occurs with a “killing” frost.  Looking at Mr. Tom Priddy’s short-term forecast, this should be about the normal Oct. 22 date.

 FAW is a tropical insect and cold weather will solve the problem. Nevertheless, experience has shown me that light frost will not do the trick, even with air temps near or at freezing.  It’s because at the soil / air level, especially in no-till fields, temperatures may remain above freezing. This is certainly true for clear sunny days, when the soil litter can obtain heat from sunlight.

Our current change in weather to rainy cool temperatures will slow this insect down. In addition these conditions will select in favor of the cool season grass that have recently been planted. You will need to continue scouting of these new stands, but weather is looking more favorable.

At risk crops remain the same, with the possible exception of soybeans. Most of these should be beyond the stage that leaf damage will be important. Sowing or renovating pastures, waterways, and cover crops with any small grass needs to be scouted for FAW.  Sowing wheat earlier than the Hessian Fly free date will increase the risk of FAW problems. Even sowing on or after the Hessian Fly free day may not provide control if the normal killing frost is late. 

Having talked to many producers, consultants, and farm service personnel, it is apparent that the problem remains in detecting the infestation. Control, once the infestation has been spotted, does not seem to be a problem.

Several common questions continue to come up:

Q.  If I spray for the FAW now, will that prevent a future infestation?

A.  No. You will probably get some residual activity from your insecticide, but if the weather stays warm, the insect’s life cycle will outlast the residual. As the weather grows cold, the application will be unneeded.

Q. If I treat my wheat seed with an insecticide, will that control FAW?

A. No, the rates we use on wheat in KY are meant to control very small sucking insects like aphids and Hessian flies. Think how much more massive a FAW caterpillar is than an aphid. This is a rate problem, not whether or not the insecticide would kill FAW.

Q. My pasture is mowed off. Has FAW killed my pasture?

A. No, it is very unlikely that FAW will kill an established stand. You will lose your yield, e.g., hay, stockpile grazing, etc.  There is little difference in FAW and cattle feeding; FAW just have smaller feet!

Q. FAW has eaten up my newly sown pasture / waterway / wheat; has it killed my seedlings?

A.  This is impossible to answer without waiting & watching for re-growth. FAW does not usually kill established grasses. However, if the root system is not well established, some seedlings may die.  My experience with wheat tells me you should be careful about reseeding.  I have seen FAW graze off a field, making it look dead, then the producer reseeding as soon as possible and ending up with a “double seeding”.  This results in many problems in the spring.

Fall Armyworm Moth Flight – Has begun to drop, but still plenty around!

Doug Johnson, Extension Entomologist

Figure 1. 2012 Capture of FAW

The second flight of fall armyworm (FAW) has begun to drop as indexed by the UK-IPM pheromone baited trap in Princeton, KY. Nevertheless, the capture for the trap-week ending Sept. 20, 2012, is still greater than the peak capture during the outbreak of 2007. (See Figure 1.) So, hopefully, we are on the downhill side of this problem, but there will still be plenty of moths to lay eggs over the next couple of weeks.

Producers, consultants and farm service personnel are still calling to report infestations and ask questions. There does not seem to be much problem with obtaining control once an infestation is found, but many folks are still not finding the infestations until considerable damage has already been done. Certainly, most callers are interested in what is coming next. Although the moth capture gives us a heads up and an indication of the level of risk, they will never tell us what is happening in a given field.

Our current weather may tend to extend the time the caterpillars are present. Our cooling temperatures are not cool enough to hamper the worms, but their development may slow down, increasing the days they will be in the damaging stage.

The crops at risk remain the same. Grass crops (pasture, hay, lawns) still remain in danger. Still, soybean problems appear to be coming from the caterpillars “marching” out of grasses in to the beans. Don’t neglect to check a field interior now and again. FAW will lay their eggs in soybeans, but grasses are by far the preferred egg laying site.

Anyone planning to plant wheat, rye, or renovate / restore any “small” grass pasture or hay field should give strong consideration to waiting for a while longer to seed. Experience tells me FAW caterpillars will be around until frost, even if not in the large numbers present now.

Fall Armyworm Moth Counts Continue to Climb!

Doug Johnson, Extension Entomologist

Capture of fall armyworm (FAW) moths has increased for the second week in a row, and this week by a huge margin (Figure 1.). Not only has an unprecedented second distinct FAW flight begun, it has surpassed this year’s previous peak in size. The August flight which reached 549 moths / trap-week for the trap-week ending Thur., Aug 16th, now stands at 675 moths / trap-week for trap-week ending Sept 13, 2012. Will it go higher? Only time will tell.

In addition to the numbers of FAW moths being captured, there is a second situation that gives me pause. This 2nd flight peak will be earlier in the season than we normally see, if one occurs. If the current numbers turn out to be the largest capture, then the peak will be approximately two weeks earlier than we would normally expect. Putting this in perspective, if we have an average frost date of Oct 22nd , this flight has approximately 5 ½ weeks for the caterpillars to develop and feed on our crops as opposed to a more normal 3 weeks. If frost is late this interval could be even longer.

Remember, the graph above represents MOTH flight. Moths are not the damaging stage of this insect. These moths were captured because they were seeking female mates. Once mating and egg lay has occurred, we will begin to see very small FAW caterpillars. This is the beginning of the damaging stage. This will likely take a week, perhaps two, depending on temperatures. Of course, further south and west (toward the upper Mississippi River bottoms) caterpillars will appear sooner. Further north and east (in the western 1/3rd of KY), caterpillars will take longer to appear. Fortunately, the traps in Lexington have just this week captured FAW for the 1st time this year; and the numbers are small. I doubt that there is any unusual risk in central and eastern portions of our field crop / pasture-hay production area.

Remember, as well, that these trap counts will NOT predict what will happen in an individual field. There is really no easy way to detect the presence of this pest. One must go to the field and look for their presence / activity. I would start by sweeping in grasses that have received enough rainfall to start re-growth. This will be a preferred egg laying location. FAW will lay eggs in soybeans, but they are not the preferred host. If this generation acts like the last, most soybean infestations will start with worms moving from grass waterways, roadsides & pasture/hay fields.

Crops primarily at risk will be newly planted wheat, pasture / hay production and very late maturing soybeans.

There is really only one thing that can bring this cycle to a halt….cold weather. FAW is a tropical insect that cannot overwinter in KY. In fact, under historic conditions, FAW cannot overwinter outside the gulf coast areas. So, vigilance will be needed until a hard frost stops their northward migration. Certainly, this is not the year for early planting of wheat.

Also, see Kentucky Pest News No. 1318, Sept. 11, 2012 at:

http://www.ca.uky.edu/agcollege/plantpathology/extension/kpn/current.html

and the Wheat Science News Vol.16, No.5, Sept. 7, 2012 at:

http://www2.ca.uky.edu/wheatscience-files/Sept_6_2012_Wheat_Newsletter.pdf

for the article: “The Effect of Insects on Wheat Planting Decisions” for a more complete look at FAW and other arthropod pests on our upcoming wheat planting season.

Armyworm / Fall armyworm Problems Increase

Doug Johnson, Extension Entomologist, University of Kentucky

Feeding of one or several “armyworm” species appears to be on the increase. I cannot be completely sure which species are causing the damage, and it is likely that two species, the armyworm also know as True armyworm and the fall armyworm are the most likely culprits.

Fall armyworm moth captures in the IPM pheromone baited traps at Princeton, KY have skyrocketed in the last two weeks, going from 0 to 131 and currently to 550 moths captured in the trap week ending 9/16/12. This problem was reported in TN, AR & MS last week and recently in MO.

Fall Armyworm Moth Flight Increases, worms sited!

Doug Johnson, Extension Entomologist


Capture of fall armyworm (FAW) moths in UK-IPM pheromone-baited traps has increased substantially over the last week. Until recently, there had been no FAW moths captured at the UK-REC in Princeton (Caldwell Co.) and only small numbers in Cam Kenimer’s trap line in Fulton Co., KY. In the trap week ending 9 Aug. 12, the capture increased from zero to 131 moths / week at the UK-REC, though the Fulton Co. trap counts remain low.

It is difficult to know what the increase at the REC might mean, however, a producer in Caldwell Co. (the county in which the REC is located) has seen a small number of FAW crossing a road. Additionally, reports from counties further east and south report FAW infestations in pastures (they must have gotten some rain!!!). Add to this reports from our colleagues in states to the south, indicating increases in FAW activity in areas that have received recent rains; and I think this adds up to checking to make sure they are not present in your fields.

At this time of year FAW are primarily a risk to soybeans and pasture / grass hay fields. They would also attack corn, but we are too far along for this to happen in our major corn growing area. Nevertheless, this insect can be quite voracious so producers of soybean and pasture / grass hay are encouraged to check your fields to look for this critter.

FAW is a migratory pest in KY and is only an occasional pest of soybeans; but it can cause serious damage if infestations are large. Soybean is not a preferred host crop, but it may be infested especially in years when grass crops are not available. Given our unprecedented drought that is certainly the case this year. This is primarily a defoliating pest but can feed on pods as well.



FAW on corn leaf.



Newly hatched FAW are white with a black head, but the body darkens as it grows. Full-grown larvae are up to 1 1/4“ long, have black bumps, and may be light tan to dark green. The black head will have a distinct inverted “Y”.

Thresholds for this pest in soybean are not well established in KY. Like corn earworm, if sampling in wide row beans with a 3’ shake cloth, the threshold would be an average of 2 worms per row-foot. If sweeping narrow rows with a 15” sweep net, an average of 9 larvae per 25 sweeps would indicate a need for control.

Thresholds for FAW in pastures / grass hay fields are also not established. Clearly the insect can do great damage in some situations. In states further to the south of us 4-6 or 5-7 worms per square foot are used as the economic threshold. Though the season would be earlier and the grass variety different, that is probably as good as starting place as any.

If insecticidal control is required check ENT-13 (for soybeans) or ENT-17 (for pasture / grass hay) for a listing of registered insecticides. These publications may be obtained from your county extension office or on the web at:

                  http://pest.ca.uky.edu/EXT/Recs/welcomerecs.html

Relative Efficacy of Single and Stacked Corn Traits Against Insect Pests in Kentucky

Ric Bessin, Extension Entomology, University of Kentucky
Latest update: May 2011

Corn Types	Insect toxins		Dual modes of Action	ECB	SWCB	BCW	CEW	FAW	WCRW	Min. Refuge Requirement
YieldGard CB	Cry1Ab			++++	++++		++	++		20% block
Herculex 1	Cry1F			++++	++++	++	+	+++		20% block
Agrisure CB	Cry1Ab			++++	++++		++	++		20% block
YieldGard RW	Cry3Bb1								++	20% block
Herculex RW	Cry34Ab1, Cry35Ab1								++	20% block
Agrisure RW	mCry3A								++	20% block
YieldGard Plus	Cry1Ab, Cry3Bb1			++++	++++		++	++	++	20% block
Herculex Xtra	Cry1F, Cry34Ab1, Cry35Ab1			++++	++++	++	+	+++	++	20% block
Agrisure 3000GT	Cry1Ab, mCry3A			++++	++++		++	++	++	20% block
YieldGard VT3	Cry1Ab, Cry3Bb1			++++	++++		++	++	+++	20% block
YieldGard VT2 Pro	Cry1A.105, Cry2Ab2		yes	++++	++++	++	+++	++++		5% block
YieldGard VT3 Pro	Cry1A.105, Cry2Ab2, Cry3Bb1			++++	++++	++	+++	++++	+++	20% block
SmartStax	Cry1A.105, Cry2Ab2, Cry3Bb1, Cry1F, Cry34Ab1, Cry35Ab1		yes	++++	++++	+++	+++	++++	+++	5% block
Optimum Intrasect	Cry1Ab, Cry1F		yes	++++	++++	++				5% block
Agrisure Viptera 3110	Vip3Aa, Cry1Ab			++++	++++	+++	++++	++++		20% block
Agrisure Viptera 3111	Vip3Aa, Cry1Ab, mCry3A			++++	++++	+++	++++	++++	++	20% block
AcreMax 1	90% Cry1F, Cry34Ab1, Cry35Ab1 + 10% Cry1F			++++	++++	++	+	+++	++	RIB + 20% block
AcreMax RW	90% Cry34Ab1, Cry35Ab1								++	RIB
SmartStax Refuge Advanced/Complete	Cry1A.105, Cry2Ab2, Cry3Bb1, Cry1F, Cry34Ab1, Cry35Ab1 + 5% refuge seed		yes	++++	++++	+++	+++	++++	+++	RIB

ECB = European corn borer
SWCB = Southwestern corn borer
BCW = Black cutworm
CEW = Corn earworm
FAW = Fall armyworm
WCRW = Western corn rootworm


‘ + ‘ = Poor to fair control
‘++’ = Good control
‘+++’ = Very good control
‘++++’ = Excellent control
May 2011

X-Large Fall Armyworm Caterpillar Population Should Be Past.

The X-large population of fall armyworm (FAW) caterpillars generated by the X-Large population of FAW moths in late August (as indexed by UK-IPM trap counts, See: KPN 1245 Aug 31, 2010) should be past. This does NOT mean that the threat from FAW is over. It simply means that the large pulse of caterpillars generated by the extraordinary number of moths have completed the damaging stage of their life cycle. We do have evidence (especially forage fields having to be treated a second time) that this pulse did cause some producers x-tra trouble.

My best guess is that the FAW caterpillars produced from the X-large moth flight are now in the pupal (resting) stage, from which adult moths will emerge. So it is possible that another large flight could occur this fall, depending upon temperature. The only other recent, large, fall occurring, FAW population for which we have record, occurred on Oct. 5, 2007. This led to large numbers of FAW mostly feeding on volunteer corn (fortunately) in area wheat fields.

Regardless of whether or not we see another large surge of moths, FAW caterpillars will be present until at least the first killing frost and one should continue to monitor crops at risk. By now corn and most soybeans and sorghum are no longer in danger. Grass and alfalfa forages, especially newly established stands are at greatest risk. Additionally, any newly established grass stands including wheat, lawns and grass covers for construction and reclamation should be watched.

Fall Armyworm Flights Increase --- Again!

Fall armyworm (FAW) moth counts are again increasing in the UK-IPM pheromone baited trap at Princeton. This is not completely unexpected. We see some sort of flight increase about this time every year. As to whether or not it is important is really a matter of when the caterpillars appear in relationship to your crops.

At present FAW counts remain lower than the numbers associated with the known outbreak of 2007 and if they continue to a similar number, the peak will be a week or so later. The caterpillars from that peak could be a threat to early planted wheat.

In 2007 several individuals reported large FAW populations in wheat fields. However on the whole these populations were feeding on the volunteer corn and not the wheat. If you find large numbers of caterpillars be sure to distinguish on what they are feeding. Even though the numbers are large they may be (and likely are) doing no harm at all.

The crop most threatened by the fall occurrence of FAW is newly seeded grasses. This could be wheat but are generally, hay fields, lawns and cover for roadsides, construction sites etc. In the very early stages of these seedling grasses FAW can kill the plants. Once a good root system is established plant death is unlikely.

FAW will be present until the first hard frost. These are not cold tolerant insects; they migrate in annually from the gulf coast states. So, once cold weather becomes the standard this insect will disappear.

If insecticidal control were to be needed FAW will not be hard to kill in these seedling systems. Any product labeled for FAW and the crop of interest will provide sufficient control. One really only needs to reduce the population until cold weather arrives. BE very, very wary of replanting. It is often the case that damaged plants will survive and replanting often results in a double stand.

Late Breaking--- Fall armyworm on soybean making impressive appearance in nearby southern states!

Reports from Extension Entomologists in Tennessee and Arkansas indicate that fall armyworm (FAW) populations in soybean are building up earlier and in larger numbers than normal. In Arkansas fields are being treated for a combination of FAWs and Corn earworm (CEW). In Tennessee the populations do not appear to be as widespread but some fields were in need of treatment. We can have this combination of insects in Kentucky soybeans. It is unusual, but it does occasionally happen. Likely places to check are late planted beans and fields in which the canopy has never closed. Historically, when this problem has occurred it is usually found in the Purchase area and the southern tier of counties in the Pennyrile area. No problems have yet been reported in Kentucky. Nevertheless, producers, consultants and scouts should be scouting regularly for these pests. They are in Kentucky; that is not the question. The question remains as always; are populations large enough to warrant a control?
See Kentucky Pest News at: http://www.uky.edu/Ag/kpn/kpnhome.htm for more detail on late season soybean insect pests.