Tuesday, July 26, 2016

On July 21st, I received word that Eddie Meeks (crop consultant) found sugarcane aphids while scouting in a sorghum field near Black, TX. Black, TX is approximately halfway between Hereford, TX and Friona, TX on US Highway 60. This is the farthest northwestern location that the sugarcane aphid has been reported on the Texas High Plains.

Photo by Mr. Eddie Meeks

Thursday, July 14, 2016

Sugarcane Aphid in Crosby County

Sugarcane aphids have been found in sorghum in northeastern Crosby County, just west of McAdoo. There were mixed populations of SCA and yellow sugarcane aphids, both at low levels. Less than 5% of plants were infested, and colonies were small with 5-10 aphids each. Only one winged adult was found. Aphids were only on the north side of the field. 

Wednesday, July 13, 2016

Managing Sugarcane Aphid on the Texas High Plains

Now that sugarcane aphid has been found in Floyd County it is safe to assume that we will shortly find it in surrounding High Plains counties. We all went through the aphid invasion last year and there is no need to go in to great depth on scouting and management, so I will just hit the highlights from lessons learned last year. If you want to read our complete 2016 sugarcane aphid management publication it is here.

Early planting is going to pay off

The earlier the aphid arrives during crop development, the more damage it can do. Infestations prior to boot can cause sterile panicles and decrease yields to essentially zero. Infestations at or after flowering, while still very serious, are somewhat less potentially damaging. This is why our treatment thresholds vary by crop stage.

Treatment threshold:
Pre-boot: 20% of plants with aphids.
Boot: 20% of plants infested with 50 aphids per leaf.
Flowering to Milk: 30% of plants infested with 50 aphids per leaf.
Soft dough through dough: 30% of plants infested, localized areas with heavy honeydew, and established aphid colonies.
Black layer: Heavy honeydew and established aphid colonies with treatment only for preventing harvest problems.

Our earlier planted sorghum has either finished flowering or is now flowering and has moved to the place it can withstand more aphids. In part this might matter because we have a relatively high number of beneficial insects in the system, and they have a better chance of keeping populations below treatment thresholds when those thresholds are higher. And even if one insecticide application is necessary, the need for a second application is far less likely in a much more mature crop.

Weekly scouting is a must

Under hot, dry conditions, the reproductive capacity of this aphid (which is born pregnant) is something approaching Shock And Awe, and everyone who went through the 2015 season will agree.  Missing a weekly scouting might mean missing populations low enough to be brought under control with insecticides. In 2015 we had many fields that were sprayed too late and adequate control was not achieved without a second application. Once the aphid has been found in a field, then twice-weekly scouting is important. Last year I would have linked to our guide to recognizing the sugarcane aphid, but this year I think we all know what the enemy looks like.

"Tolerant" hybrids are susceptible hybrids

There are a few hybrids with resistance to sugarcane aphids, although the seed industry chooses to call these "tolerant" hybrids because they rightly don't want to give the impression they are bulletproof. Our best resistant hybrids are what could be called moderately resistant, and this won't stop the aphids from reaching treatment thresholds. It may slow them down, and it may let the beneficial insects have more time to exert control, but all other things being equal it is merely a delaying action. Fields of "tolerant" hybrids should be scouted and sprayed based on the treatment threshold just like fields of completely susceptible hybrids.

Insecticide choice matters - a lot

Last year saw everything in the book, and some things not in the book, being thrown at sugarcane aphids. Many of these insecticide products were our old aphid standards, and what we found was that they were not very good at killing aphids, but they were very good at killing beneficial insects (the big guns in aphid control after an application). Our insecticide trials confirmed this; we had massive aphid resurgence where we killed the beneficial insects. There are only two good insecticide choices for sugarcane aphid: Sivanto and Transform. Both of these provide high efficacy with minimal impact on beneficial insects.

Make the first application count

Last year we observed insecticide applications of Sivanto and Transform made with high rates and plenty of carrier volume most often did such a good job of control that the few surviving aphids were cleaned up by beneficial insects. Conversely, we observed that fields sprayed with lower rates and/or insufficient carrier volumes frequently did not get control and required a second application.

Experience is a good teacher

This pest is manageable. Last year was a bit of trial and error, but after one growing season of intense aphid pressure we are much better equipped in 2016.

Sugarcane Aphid in Floyd County, Probably Other Counties

Post by Blayne Reed, Extension IPM Agent in Hale, Swisher and Floyd counties.

Independent crop consultants have found sugarcane aphids in Floyd County.  The populations are very light, hard to find, and as of this morning, only along the ‘waterways’ leading westward up the caprock or on the very few fields off the caprock farther east.  These draws cut a pretty good way westward into Floyd and Crosby counties.

One of the fields confirmed with SCA was actually in southwestern Floyd at the edge of one of these draws.  It is very likely we have SCA farther west right now than we realize, but at a level very difficult to find without a fleet of entomologist in every field.  At face value this looks like the same infestation pattern we have had for the two previous years with the aphids either flying on the easiest route or pushed by wind up these ‘funnels’ and drawn to the irrigated sorghum fields on the edges of the draws.  In terms of population today, the number of infested plants is well  below 1% with less than 10 aphids per colony.  We all know how fast this can change and all of our consultants involved with these finds have already re-visited these few infested fields with little change so far.  There are not many winged aphids yet.

This is a very quick and early find by several of our outstanding area independent crop consultants in the region.

Thursday, July 7, 2016

Reports of Sugarcane Aphid in Oklahoma

I received a call this morning from a County Extension Agent from Lipscomb County in the Texas Panhandle. He had seen on Facebook that sugarcane aphids were found near Clinton, OK. As a crow flies this about 175 miles east of Amarillo, TX on interstate 40. I contacted Dr. Tom Royer, Oklahoma State University entomologist, to see if this could be confirmed. He stated that low numbers of sugarcane aphids were beginning to be found in several Oklahoma counties. So, this is just another report of an increase in sugarcane aphid activity.

Aphids Found in Mills County, Reported in Comanche, Hamilton Counties and More

Tom Guthrie, County Extension Agent Ag, in Mills County is reporting building populations of sugarcane aphid on sorghum in Mills County. Some fields have exceeded the economic threshold. He has credible reports of sugarcane aphids in Comanche and Hamilton counties.  Additionally, a private consultant has reported finding aphids in Nolan, Fisher and Jones counties at treatable levels.

Sugarcane aphids on sorghum in Mills County. Photo credit: Tom Guthrie.

Aphids Found in Mills, Comanche, Hamilton Counties and More

Tom Guthrie, County Extension Agent Ag, in Mills County is reporting building populations of sugarcane aphid on sorghum in Mills, Comanche and Hamilton counties. Some fields have exceeded the economic threshold. Additionally, a private consultant has reported finding aphids in Nolan, Fisher and Jones counties at treatable levels.

Sugarcane aphids on sorghum in Mills County. Photo credit: Tom Guthrie.

Saturday, July 2, 2016

Sugarcane Aphid in Sorghum near San Angelo

Joel Webb, EA-IPM Runnels and Tom Green counties, today has identified sugarcane aphids in the San Angelo area.  This is the nearest confirmed growing season report of the sugarcane aphid to the High Plains area.

The aphid was confirmed as overwintering right here in Hale County and was found on native Johnson grass in Lubbock, Hale, & Swisher Counties earlier this spring, but since that time has fallen off the ‘radar’ with no more colonies found in our area.  We assume healthy populations of predators are to credit for the disappearance of the aphid from our area, but we cannot be certain.  With no native sugarcane aphids to monitor, we have been and will be watching the migration of the aphid from the south while anticipating and bracing for their arrival on the High Plains.  In the Valley, Coastal Bend, and Hill Country, the aphid has been an economic pest this year, but reduced in population compared to recent seasons.

(Text copied from Blayne Reed's 7/1/16 newsletter)
We have a concise guide to recognizing the sugarcane aphid.