"White" Sugarcane Aphid Arrives on the Souther High Plains

The sugarcane aphid arrives on the southern High Plains

Blayne Reed, Patrick Porter and Ed Bynum

We have been watching for the possible arrival of the sugarcane aphid, Melanaphis sacchari, on the High Plains, and we must now report that it has been found.  Clay Golden, an independent crop consultant serving the area, discovered a small pocket of the aphids on soft dough stage sorghum in an extreme northwestern portion of Floyd County on September 9, 2014.  Upon his find Clay enlisted the aid of Blayne Reed, EA-IPM Hale & Swisher counties, who supported Clay’s identification of the aphid.  Dr. Pat Porter and Dr. Ed Bynum were then presented with aphid samples and confirm the identification. 

Given the proximity of this aphid population to neighboring counties; ½ mile from Briscoe, 2 miles from Swisher, and 7 ½ miles from Hale, combined with some possible smaller and un-confirmable sugarcane aphid hits in nearby sorghum in Swisher and Hale and that this aphid is often dispersed by prevailing winds, it is logical to assume that it is present over a wider area encompassing small portions of all four counties. Many of the aphids in Clay’s sample were at the developmental stage just prior to becoming winged adults, so we expect that further dispersal is happening now.

After Clay’s discovery, we asked for some help and perspective from our downstate colleagues who have been dealing with this pest since last year. Here is a summary of information from Raul Villanueva, Robert Bowling, Stephen Biles and Mike Brewer.

1) It takes ten days to two weeks for isolated aphids to establish significant colonies on sorghum. So scouting should be concentrated on finding the first few infesting aphids in the field on lower leaves.

2) Stephen Biles, Extension Agent IPM in Victoria, has done some very recent work on an action threshold in sorghum in the reproductive stage. Stephen’s work suggests that a good action threshold for treating is an average of 100 aphids per leaf. He suggests sampling 10 plants per location within a field (several locations) and picking the leaf below the flag leaf and an additional leaf from the middle of the plant. If there are an average of 100 aphids per leaf (2,000 total on all 20 leaves), then come back in two days and re-sample to see if the population is increasing. If the numbers are going up then consider treating. If the numbers are not going up then don’t treat but continue to monitor. Observations of this aphid from downstate have shown that some populations can crash very quickly. We don’t know how to predict which populations will crash and which will increase.

3) Transform (available under a Section 18 exemption) is the most effective insecticide. It can be used at a rate of 0.75 to 1.5 ounces per acre. Our downstate colleagues have had good results at the 0.75 ounce rate, but good coverage is essential at this rate. They strongly recommend 10 gallons of carrier volume per acre by ground and, if this can’t be achieved with aerial application, they recommend a bare minimum of 5 gallons per acre and a minimum rate of Transform of 1.0 ounces per acre. (Which is to say the 0.75 oz rate of Transform may not work by air at 5 gallons per acre.) We do not know if a 1.0 oz rate can be put out at less than 5 gallons per acre. Our colleagues have also said that Dimethoate is not a good option because it is not a consistent performer.

This aphid is not going to be Atilla the Hun on the High Plains. Invasive species often do the most damage in their first year or two of invasion before natural enemies can respond to the new pest.  For this year at least, the aphid is arriving late in the season and will not be infesting whorl stage plants which will be limiting the aphid in time to build into an economic problem. We also have products that have proven to control this aphid. This, combined with the implementation of good scouting techniques, give us confidence that this aphid can be effectively controlled if necessary. The Section 18 allows for two applications of Transform (1.5 oz maximum per application), with the total application for the season not exceeding 3.0 ounces. There is also a mandatory 14-day waiting period between the first and second application. So this gives us six weeks of good control, assuming 14 days of activity from each application. This should be sufficient to carry us through harvest.

It is not known whether the sugarcane aphid can overwinter on the southern High Plains; it is a subtropical species and overwintering survival is very much in doubt. We also do not know how fast the sugarcane aphid can reproduce given the predicted cooler temperatures in this week’s weather forecast.  We will have to watch for it next year when our sorghum is in the whorl stage, but for this year we can handle the problem if it arises.

The sugarcane aphid is fairly easy to recognize and distinguish from our other common aphids. Look for black-tipped antennae and legs. Dr. Ed Bynum recently posted an article on identifying the sugarcane aphid: http://amarillo.tamu.edu/files/2010/11/PPU-V6i6-5-23-2014.pdf . Our publication Sugarcane Aphid: A New Pest of Sorghum is available here: http://www.agrilifebookstore.org/product-p/ento-035.htm . We will of course keep you informed of new developments.

            I should also note, particularly to this audience, a few details.  Today the sugarcane aphid is only officially confirmed in Floyd County.  This confirmation comes from a currently very small pocket population that remains hard to find within that field, even for Clay who has walked this field all season long and visited the exact spot several times now.  I have not found any pockets of the sugarcane aphid in our program fields.  Whorl stage sorghum type hay crops could be at the highest risk.  I would also like to doubly stress that it is very late in the season and we have a proven product in our pest control toolbox if need be.  While the history and proven damage of this aphid makes it worth a closer than normal check in area sorghum for this late in the season I would personally like to sum it up this way: These guys are mean and nasty, but they came wearing Bermuda shorts, they did not pack a coat, and the ‘wanted dead not alive’ posters are hot off the press.

Blayne Reed

2014 Hale County Field Day

                It is so obvious that it sounds almost cliché to state that those in today’s agricultural production face many challenges.  This has been true for generations but the fact seems to deepen every season.   As one of the world’s most dependable commodity breadbaskets, Hale County producers are again in the thick of it.  Some of our County’s biggest production issues are dwindling irrigation sources, weed control, incorporating new technologies and genetics, and making the most out of every acre with dwindling resources.  Standing with our producers remains their old standby friend and supporter the Texas A&M AgriLife Extension Service.  The Texas A&M AgriLife Extension Service continues to work for the producers at the State, Regional, District, and County level offering unbiased research based solutions to the problems producers face today. 

                On September 18, the Texas A&M AgriLife Extension service in Hale County will hold a Field Day at the Halfway Experiment Station to showcase some of the latest work being done toward answering many of the most pressing issues area producers face today.  From 8:15 – 8:30 am we will hold a brief sign in at the Halfway Station located 14 miles west of Plainview on Highway 70.  At 8:30 we will meet Dr. Jim Bordovsky, Research Engineer, Halfway, in his research plots to discuss his latest work in irrigation timing and scheduling in cotton.  At 9:30 we will catch up with Dr. Mark Kelley, District Cotton Agronomist, to discuss emerging cotton genetics, technologies, and some of his harvest studies.  At 10:15 we will move to the turn row near Dr. Wayne Keeling’s, District Systems Agronomist, herbicide plots to learn about his studies involving some of the new cotton herbicide technologies soon to be released.  At 11:15 we will migrate over to Blayne Reed’s, EA-IPM Hale & Swisher, sorghum planting date study for economic and IPM management for a first hand view of that trial, a rundown of the current IPM situation, and some IPM tips for 2015.  By noon we will meet back at the Halfway Station headquarters for a quick lunch either in the east meeting room or under a shade tree where Dr. Kelley will re-engage us for a quick harvest aid rundown.  By 1:00 pm we will follow Blayne off station to Klepper Farms near Edmonson to tour an outstanding sorghum variety trial where Phillip Thornton, Sorghum Partners, and Blayne will give a guided tour of one of the trials replication blocks.  

                The cost to attend the event will be $15.  A quick lunch and 3 CEUs will be provided.  We will see you Thursday, September 18, 2014 for the Texas A&M AgriLife Extension Service’s Hale County Field Day.

Sorghum Midge 2014

Sorghum Midge

                Much of our later planted sorghum will be coming into bloom this week.  This means that the long anticipated sorghum midge season is starting.  Today, August 18, 2014, I was in a southwestern Swisher County sorghum field that was at boot to bloom stage.  Only about 5 % of the heads had blooms yet, but every head with blooms also had a midge.  This is not a treatable level of midge… yet.  As the field progresses farther into bloom I would expect to find additional midge infesting an economic level of heads.

Midge are tiny Dipterans, or flies, that feed exclusively on sorghum type plants.  The adult midge only lives less than one day, just long enough to lay eggs into blooming sorghum.  The tiny resulting maggot feasts on a single developing grain from within consuming it fully only to emerge as an adult a short time later (usually about 2 weeks) as an adult to start the process over.  Midge cannot overwinter in our area and must migrate from the south every growing season, usually hopping generationally from blooming sorghum field to blooming sorghum field.  Johnson grass can also harbor the midge life cycle.  Sorghum fields blooming early in the growing season are normally immune to midge damage, as the midge typically do not arrive in force until an average date of August 4^th. 

We have been finding midge at sub-economic levels in sorghum since late July.  So far we have not had any fields reach ET (economic threshold) for midge but I really think that is about to change.  The midge population has been gradually growing on our early planted sorghum and the abundant Johnson grass population that our early summer rains have fired.  As sorghum fields enter bloom, I recommend scouting daily, and if your later sorghum planted sorghum is near a healthy Johnson grass population or an earlier planted field I recommend extra caution. 

                When scouting for midge, I prefer to make use of beat buckets or jugs by placing the bucket over the blooming head, tiling downward and shaking vigorously.  Midge should be shaken loose and counted.  A minimum of thirty plants per field should be checked, but total number needed to be checked will vary depending upon field size.  Another good method for use on windy days involves enveloping the blooming head in clear plastic, disturbing the head and counting midge trying to escape.  While in bloom, sorghum should be checked daily for midge starting about 11AM, temperature depending.

                The ET for sorghum midge at the current market level for grain sorghum should be near 1 midge per head during bloom stage.  This ET level should be slightly lower for seed milo, contracted grain value depending. 

Please call or come by with any questions,

Blayne Reed

White Lined Sphinx Moths

The Sudden Appearance of Large Horned Caterpillars Cause Concerns

Blayne Reed, Dr. Pat Porter, Dr. Ed Bynum

                In the past few days I have received multiple phone calls and questions regarding some very large, horned caterpillars.  This appears to be the annual arrival of the white lined sphinx moth.  I alluded to these hornworms being thus far strangely absent from Hale & Swisher in the June 27 edition of the Plains Pest Management Newsletter.  Since that time they have made their presence known from Hale Center to Vigo and beyond.  Dr. Ed Bynum reports finding this caterpillar north of Amarillo and Dr. Pat Porter has reports of it near Muleshoe.   

                As an adult moth the white lined sphinx is also commonly referred to as the humming bird moth or the hawk moth.  The moths are large, somewhat motley colored interesting Lepidoptera that lean toward mimicking humming birds in behavior and body shape when in flight.  There are actually several species of sphinx moths, but these tend to be the most predominate in this area.  We noted several in the area through the months of April and May.  The larva can typically grow to be surprisingly large, up to 3 ½ inches in length, are very plump, colored with a light green base with yellow, black, and sometimes white markings, and a large usually yellowish spine or horn near the tip of the abdomen.  These hornworms are known to feed on a variety of plants which include portulaca, primrose, wild grapes, and a few types of succulent trees.  Despite a fairly lengthy list of host plants, they do appear to be very picky eaters.  Over the past few years, I have noted them mostly feeding on purslane weeds, almost completely ignoring other plants and healthy foliage nearby. 

                The massive group population and potential movement of the white lined sphinx caterpillars can be very impressive, with many describing it as downright intimidating.  These worms only seem to appear in mass populations of at least thousands (if not by the million) with just one local generation annually.  The larva will feast on their preferred vegetation, devouring it quickly and fully before moving to find another pocket of that preferred vegetation with a mass migration that many describe with a statement like, “the ground seemed to be moving and wiggling.”  Meanwhile the pasture, sorghum, and cotton plants they were near or fields they were in are left almost completely untouched with any damage being coincidental. 

                Just about all of my encounters with this hornworm over the past 15 years have ended pretty well.  The sheer number of veracious larva of this size moving into production fields or healthy pasture is enough to make anyone nervous and is most certainly worth keeping daily tabs on.  To date, I have never been forced into recommending treatment for these hornworms.  The fields they have infested are eventually left almost completely unscathed with a serious hit to the weed population following either their migration away from, or eventual pupation of the larva.  I can state with some confidence this pattern of nerve racking benefit to production fields should continue this season.  I cannot be nearly so certain of a respectable outcome of this hornworm’s impact to a grape vineyard or garden plot, horticultural or vegetable.  There is likelihood that something within those situations could be what the white lined sphinx moths picky diet would find delicious. 

                If treatment for these hornworms becomes necessary it is believed a good general pyrethroid would do a good job of achieving control.  Thus far, there has not been a need for an efficacy trial in this region so this assumption has not been verified.

Please call or come by with any questions,          

Blayne Reed

Assessing a Cotton Field’s Viability after Damage

                It has been an interesting spring trying to establish viable stands of cotton this season.  We have had ridiculously dry conditions, followed by cold fronts, followed by long periods of cool wet weather with heavy rain, followed by baking conditions, followed by more rain, hail, wireworms, and of course the wind.  I have met no one who would trade the blessings of the recent rains to be rid of the troubles it has brought to the always temperamental cotton seedlings. 

Many producer’s fields from Plainview north through Swisher have had irrigated cotton seed in the ground through it all while those producers though southern Hale were a little more timid in planting this season and avoided much of the early challenges.  With each successive adversity faced, our irrigated cotton seedling stands have dwindled and several fields have lost viability.  Whether your cotton has been through one nasty event or the 10,000 pinpricks of this spring, some serious evaluations of each field needs to take place.  Luckily, there is a wealth of research and experience to help us determine whether a field has the potential to remain profitable, or if it needs to be replanted to a secondary crop.

Stand counts are the primary tool in determining whether or not a field will make, or if it needs to be replanted.  With this comes a discerning eye about what makes a surviving cotton plant.  A minimum of 27,000 fairly evenly distributed plants per acre that have a healthy growth point on June 20 have proven to maintain their profit potential, assuming no more plants are lost throughout the remainder of the season.  Gaps in a field that are larger than a foot can cause significant yield loss regardless of plants per acre counts, but cotton can compensate for gaps shorter than a foot if they aren’t repetitive.

To gather stand counts from your respective fields, the following should be helpful:

40 inch rows: 13,068 row ft. = 1 acre

38 inch rows; 13,756 row ft. = 1 acre

36 inch rows; 14,520 row ft. = 1 acre

32 inch rows; 16,334 row ft. = 1 acre

30 inch rows; 17,424 row ft. = 1 acre

I recommend measuring 1/1000 of a row ft. acre for your actual stand counts.  All surviving seedlings within this 1/1000 of an acre should be counted, and if possible, health needs ascertained if the field is viable.  I suggest taking these counts at least 4 to 5 times from across your fields taking into account stronger and weaker areas.  Often many more counts are required for borderline stands or stands that are highly variable.  When finished, simply average all stand counts for that field, multiply by 1000, and make your decision about the future of that field this season.  The 27,000 plants per acre mark is a pretty good yardstick.  Other factors such as field history, water availability, expected pest pressure, current pest pressure, root health, rotation needs, weed pressure, and nutrient availability are just a few factors that could come into play.

Most producers would like to know a damaged field’s potential immediately following damage.  This is almost impossible to ascertain and giving the fields 2 to 7 days, situation depending, following damage will be helpful.  Many times seedlings can look healthy, or at least have a respectable “re-growing” point shortly after any new hail or wind damage, but seedling disease, additional blowing conditions, or some other factor will inevitably and unpredictably finish many off.   By the same token, seedlings that look to be little more than sticks can recover quite rapidly if there are any soft and active growing points left on the plant and the root system is not ravaged to severely.  

I hope this short blog has been helpful for your decision process.  Please call or come by with any questions,

Blayne Reed