Monday, July 27, 2015

Southern High Plains Counties Reach Treatment Threshold

At a minimum, Floyd, Crosby and Lubbock counties now have sorghum fields at the economic threshold of 50 to 125 sugarcane aphids per leaf and insecticide applications started over the weekend. Blayne Reed, Extension Agent - IPM in Hale, Swisher and Floyd counties said that private consultants called in the first Floyd County applications today. Monti Vandiver, Syngenta Crop Protection and former Extension Agent - IPM, said that the aphids in Crosby and Lubbock counties are now at treatable levels. 

This is in no way meant to imply that the other infested counties don't have fields at threshold level, so it is imperative that all sorghum fields on the Southern High Plains be scouted. This aphid can go from barely noticeable to exceeding the economic threshold in as little as 5 days. All of the scouting procedures, treatment threshold and insecticide information is presented here: http://www.texasinsects.org/sorghum.html

Saturday, July 25, 2015

New Map: More High Plains Counties Have Aphids, Numbers Rising in Rolling Plains


Lamb and Swisher counties in the Southern High Plains have been added to the map of infested counties. We are seeing increasing numbers of aphids in Southern High Plains fields and a few might reach treatment threshold levels at the end of July. Additionally, aphids have reached treatable numbers in the lower Rolling Plains.

Wednesday, July 22, 2015

Sugarcane Aphid Occurrence Map Updated July 17

Note for the July 17th map that Hockley County is mistakenly listed as infested. HOWEVER, it was confirmed to be infested on July 21st. Additionally, Tom Green, Runnels and Coleman counties have more than 125 aphids per leaf as of 7/20/15. The next map will reflect these comments. 

Tuesday, July 21, 2015

Hockley and Floyd Counties Confirmed: Local Workshops Pending

Blayne Reed, Extension Agent - IPM for Hale, Swisher and Floyd counties, found several small to moderate sized sugarcane aphid colonies in a sorghum field 5 miles north of Lockney on July 21st. These aphids were below treatable levels and there were abundant yellow sugarcane aphids (a different pest aphid species) and spider mites in the field as well.

Kerry Siders, Extension Agent - IPM for Hockley, Cochran and Lamb counties, found sugarcane aphids in a sorghum field 5 miles west of Ropesville today, July 21st. The aphids were below economic threshold.

Sugarcane Aphid Workshops Pending in Hockley, Cochran and Lamb counties:

Wednesday, July 22, 9:00am, Wilbur Ellis-Levelland
Thursday, July 23, 8:30am, Platinum Bank Levelland (sponsored by Farmers Coop Elevator, Levelland)
Friday, July 24, 9:00am, CHS-Anton
Monday, July 27, 9:00am, AG Products, Levelland
Tuesday, July 28, 8:00am, CHS-Ropesville
Wednesday, July 29, 9:00am, Olton Ag Pavillion
Thursday, July 30, 9:00am, Farmers Coop – Sudan
Monday, August 3, 8:30am, Lamb County Ag Center, Littlefield
Tuesday, August 4, 7:15am, Wilbur Ellis – Earth
Thursday, August 6, 8:30am, Lewis Farm & Ranch, Morton
Monday, August 10, 8:30am, Extension Office – Cochran Co. Activity Room, Morton

Contact Kerry Siders at 806-638-5635 for more information.

Thursday, July 16, 2015

Sugarcane Aphid in Central and North Texas. July 16.

Sugarcane Aphid in Central and North Texas. July 16.  

     Sugarcane aphid infestations began to exceed treatment threshold the last week of June and early July in central (Blacklands) and north Texas.  However, many fields are currently below threshold.  Several AgriLife Extension Agents in District 8 (Blacklands) are scouting sorghum fields weekly as part of a sugarcane aphid monitoring program.  To-date, about 35% of these 13 grain sorghum fields across 7 counties have been treated for SCA.  These represent the most promising fields as the sorghum crop has suffered from heavy rains in May that stunted growth, delayed or prevented planting and fertilizer applications.  In some fields in the southern Blacklands, SCA rapidly increased to treatment thresholds following treatment for midge and stinkbugs.  Infestations have extended as far north as Grayson County, on the TX/OK border, and fields there were treated for SCA the first week of July.  Syrphid fly predators and parasitized SCA were common in June, but lady beetles only recently appeared.  In early July, hot dry weather set in and winged aphids, along with a row of new nymphs behind them, were common in fields in north Texas.   Forage sorghum producers with increasing SCA infestations are harvesting early or applying an insecticide while others planted pearl millet to avoid SCA altogether.  

Tuesday, July 14, 2015

Distribution Map Updated, Terry County Probable

Robert Bowling, Extension Entomologist in Corpus Christi, has just updated the sugarcane aphid distribution map for Texas and the southern states. The 2015 map shows counties that are under treatment threshold, at threshold and over threshold. It also shows counties where aphids have been found on Johnsongrass but not sorghum. 



We received a photo from Terry County, Texas this morning that most likely shows a large colony of sugarcane aphids and we are waiting to confirm the identification before declaring Terry County positive.

Monday, July 13, 2015

Hale County Aphids Found

Blayne Reed, Extension Agent - IPM, reported finding one colony of sugarcane aphids on whorl stage sorghum at the Texas A&M Experiment Station at Halfway today, July 13th. Aphids are not numerous; it took 20 minutes of looking to find the colony.

Thursday, July 9, 2015

Sugarcane Aphid found in an Overwintering Cage in Dawson County

Mr. Tommy Doederlein, IPM Extension Agent for Dawson and Lynn Counties, set up an overwinter cage last fall with sugarcane aphids on Johnsongrass. The cage was located 5.9 miles NNE of Lamesa, TX. Within the cage he placed two HOBO temperature data recorders. One recorder was placed on the soil surface and the other recorder was placed 2-3 inches below the soil surface.

On July 3rd, Mr. Doederlein went back to the cage and, to his surprise, found large numbers of sugarcane aphids infesting the Johnsongrass that had re-sprouted within the cage. Data from the temperature recorders showed that on the surface there had been 331 hrs with temperatures below 32 degrees fahrenheit. The lowest temperature recorded was 16.3 degrees. The other recorder positioned 2-3 inches below the soil surface recorded 37 hrs of temperatures below 32 degrees fahrenheit and the lowest temperature was 30.07 degrees.

Sugarcane aphids on Johnsongrass under an overwintering  cage. Photo: T. Doederlein
To date, the sugarcane aphids under this overwintering cage and a colony of aphids on Johnsongrass  found by Dr. Pat Porter at Lubbock are the only confirmed reports of sugarcane aphids on the Texas High Plains.

























Wednesday, July 1, 2015

Blue aphids = good news

Dr. Charles Allen is reporting finding many dead blue sugarcane aphids mixed in colonies of normally colored aphids in West Central Texas.

We expect to find that the blue aphids have been parasitized by Aphelinus species wasps. These tiny wasps can, over time, play a significant role in reducing aphid populations. The species affecting the sugarcane aphid is unknown, but Dr. Jim Woolley (College Station) and Dr. Mike Brewer (Corpus Christi) are working on the identification.

Blue parasitized sugarcane aphids among non-parasitized aphids.
Photo credit: Charles Allen

Here is a short video by Karla Cruz of an Aphelinus wasp laying an egg in a sugarcane aphid. 


Sugarcane aphid and whorl stage sorghum on the Southern High Plains

By Tommy Doederlein, Pat Porter, Blayne Reed and Kerry Siders

Sugarcane aphid arrived early in south Texas this year but its northward expansion was apparently slowed by the record rainfall. However, in the last two weeks it has made a rapid advance and was found in Lubbock County on June 29th.  This is two months earlier than the August 27th, 2014 first detection by Blayne Reed in Floyd County. Last year’s late arrival allowed us to avoid making insecticide applications. While it is still too early to guess how severe the problem might be this year, we would like to provide some information on management practices prior to boot stage.

When on whorl stage sorghum, economic populations of sugarcane aphids can result in near total yield loss because it destroys leaf cells that provide nutrition to keep the plant growing, exert the panicle and fill the grain. The worst case is a heavy sugarcane aphid infestation on whorl stage plants. Later infestations on headed sorghum are somewhat less of a problem and may only result in minor yield losses and harvest difficulties due to honeydew accumulation.

Early detection is the key to successful sugarcane aphid management. All fields should be scouted weekly from shortly after emergence until one week before harvest. If sugarcane aphids are not found in a field then the weekly scouting should continue. If light populations of sugarcane aphids are found then the scouting should occur twice per week. The doubling of the scouting interval is because of the rapid reproduction of the aphid. As Angus Catchot, Entomologist at Mississippi State University, put it, “This is the first pest I have seen that can go from ‘barely there’ to ‘Oh my God’ in five days.

Sugarcane aphids are easy to differentiate from the other aphid pests of sorghum and there is a recognition guide posted here: http://txscan.blogspot.com/2015/02/recognizing-sugarcane-aphid.html .

The treatment threshold is an average of 50 – 125 aphids per leaf on whorl stage plants. Research in Texas has shown that an average of 250 aphids per leaf is around the break point where yield declines equal the cost of control, but this many aphids can cause a honeydew and sooty mold problem. The goal is to apply the insecticide soon enough to keep the aphid numbers below 250 per leaf. Quick action is needed when fields reach the economic threshold, so don’t delay in pulling the trigger. The treatment threshold is the same for susceptible sorghum and the “resistant” or “tolerant” sorghum hybrids; once threshold is reached then insecticides should be applied as soon as possible. Blayne Reed, Extension Agent in Hale, Swisher and Floyd counties, with support from all our regional IPM specialists, is leading our 2015 research on how the “resistant” hybrids withstand sugarcane aphid. It is far too early to say anything other than, from a management perspective in 2015, expect resistant hybrids to perform in line with susceptible hybrids. The so-called resistant hybrids should be scouted like susceptible hybrids and sprayed like susceptible hybrids with the yet field-unproven hope there will be fewer aphids or better performance from the “resistant” lines.

There are two good insecticides available; Sivanto and Transform. Expect each product to provide around 10 days of control. Be sure to visit the field 3 – 4 days after the application to make sure the insecticide is working. If a follow-up application is needed after 10 days then rotate to the other insecticide. Insecticide rotation is critical for resistance management; aphids are extremely dangerous as far as resistance because they are genetic clones (no sexual reproduction and mixing of resistance and susceptibility alleles). If the mother has resistance alleles then the offspring will have the same resistance alleles; if the mother survives the dose then the progeny will survive the dose, and so will all of their progeny and their progeny across generations and growing seasons. The only way to kill these resistant insects is with the other insecticide. Insecticide rotation is the key to preventing resistance, and aphids are exceptionally adept at becoming resistant.

It is important to preserve beneficial insects – they won’t prevent sugarcane aphid from reaching threshold on the High Plains (yet), but they will slow the aphid down. There is evidence from the Gulf Coast that, after three seasons of the aphid and the beneficial insects coexisting, the beneficial insects are starting the season in high enough numbers to exert a significant amount of control on the aphids. This is not the case in the High Plains; our beneficial insects have not had the chance to arm up against the aphids and we don’t have enough of them to keep aphid populations under control. But we do have enough of them to slow the aphids down and perhaps avoid an additional insecticide spray later in the season. The best way to help the beneficials is to avoid pyrethroid and organophosphate insecticide applications; use Sivanto or Transform and let the beneficials live.  We have a new publication called InsecticideSelection for Sorghum at Risk to Sugarcane Aphid Infestations, 2015. This publication discusses insecticide choice for sugarcane aphid control and insecticides to use on other pests in fields that have sugarcane aphids in them. Other sugarcane aphid resources available at http://www.texasinsects.org/sorghum.html. We have established a statewide sugarcane aphid news website at http://txscan.blogspot.com.


We don’t know what to expect in 2015 as far as sugarcane aphid. All we know for sure is that it has arrived two months earlier than last year and is now threatening whorl stage plants. We encourage weekly field scouting until the aphids are found and then twice-weekly scouting thereafter. Apply insecticides when there are 50 – 125 aphids per leaf and use either Transform or Sivanto. Check to make sure the insecticide worked and, if an additional application is needed later, be sure to rotate insecticides in order to prevent resistance.