Category Archives: Grain Sorghum

Transform WG Insecticide Section 18 For Sorghum Approved For GA

White Sugarcane Aphids are a pest of grain sorghum that showed up in the county a few weeks ago. Thomas County has just over 1,000 acres of sorghum with high populations of WSCA. Brooks County Agents Ben Shirley and Stephanie Hollifield confirmed WSCA in Brooks County this week. The EPA has approved a Section 18 request for use of Transform insecticide on sorghum. See White Sugarcane Aphids blog post below for more information on WSCA.

Here is information from David Buntin, UGA Grain Crop Entomologist:

A Section 18 Emergency Use Exception for Transform WG insecticide on sorghum has been approved for the state of Georgia as of September, 11, 2014. Transform WG may be applied to grain and forage sorghum for control of sugarcane aphid from now until November 30, 2014. Additional details of the product use are as follows:

Foliar applications may be made by ground or air at a rate of EITHER 0.75-1.5 oz of product (0.023-0.047 lb a.i.) per acre with a maximum of 2 applications per acre per year OR 1.0 oz of product (0.03 lb a.i.) per acre with a maximum of 3 applications per acrew per year; resulting in a seasonal mazimum application rate of 3.0 oz of product (0.09 lb a.i.) per acre per year.

The minimum application retreatment interval of 14 days and a restricted entry interval (REI) of 24 hours must be observed.

A 7-day pre-harvest interval (PHI) for forage and a 14-day PHI for grain or stover must be observed.

A maximum of 50,000 acres of sorghum fields (grain and forage) may be treated in Georgia.

This product is highly toxic to bees exposed through contact curing spraying and while spray droplets are still wet. This product may be toxic to bees exposed to treated foliage for up to 3 hours following application. Toxicity is reduced when spray droplets are dry. Risk to managed bees and native pollinators from contact with pesticide spray or residues can be minimized when applications are made before 7:00 am or after 7:00 pm local time or when the temperature is below 55 degrees F at the site of application.

The registered product, Transform TM WG (EPA Reg. No. 62719-625; 50% sulfoxaflor), manufactured by Dow AgroSciences, may be applied. All applicable direction, restrictions, and precautions on the EPA-registered Section 3 label, as well as those outlined in the Section 18 use directions, except as modified by this authorization must be followed.

 

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White Sugarcane Aphids

Sorghum 013

We were looking at sorghum yesterday and saw many, many aphids with a lot of honeydew on the lower leaves. Some sorghum is not producing heads just yet. The aphid turns out to be a new aphid in the state, white sugarcane aphid(Melanaphis sacchari). The initial problems found with these aphids in Texas were discovered during harvest, since the large amount of sticky honeydew produced by aphids choked combines and losing grain. UGA Extension Grain Etnomologist Dr. David Buntin says, “Subsequent reports find the aphid in 9 total counties in the southwest quadrant of the state Marion, Decatur, Early, Seminole, Colquitt, Taylor, Terrell, Randolph, and Tift counties.” (Now Thomas.)

White Sugarcane Aphids 007

Here are some more notes by Dr. Buntin:

“The white sugarcane aphid (WSCA) has occurred in Florida since 1977 and Louisiana since 1989 feeding on sugarcane.  About 2 years ago the aphid shifted its host preference to grain and forage sorghums. First found in Texas, this new strain has rapidly spread eastward across the southern United States in 2014 and is now widespread in Mississippi, Louisiana, and eastern Texas, and Arkansas.  It is expected that WSCA will continue to spread rapidly throughout Georgia over the next few months.  It is important to scout sorghum fields in your area for its presence. It is fairly easy to identify.  Wingless forms are a uniform pale cream to yellow with black feet and black cornicles (the small tubes present on the end of the back).

White Sugar Cane Aphid-2

White Sugar Cane Aphid - Sorghum 005Where it has been found in Georgia, it is present in many fields at very high numbers of several thousand aphids per plant across entire fields. The aphid sucks plant fluid and these large populations are causing injury to the plants including death of leaves and sometimes plants. The aphid remains present in field until harvest. It produces large quantities of honeydew, a sticky sugary substance that adheres to the plants, which may interfere with harvest and may damage combine harvest equipment. Entomologist in Texas, Louisiana and Mississippi report 20 to 50 % yield loss and sometime the total loss of the crop from harvest damage.  A tentative threshold is: treat if more than 30% of plants are infested AND there is an average of 100 – 250 aphids per sorghum leaf.  This publication from Texas AgriLife Extension shows the different aphids on sorghum and information about white sugarcane aphid biology and damage: http://nueces.agrilife.org/files/2014/05/Sugarcane-Aphid-Publication.pdf   Interestingly, a study by Kathy Flanders at Auburn University suggests this new strain prefers sweet, grain and forage sorghum over sugarcane and it does not attack millets.

Adult White Sugarcane Aphid

WSCA is difficult to control and populations may bounce back quickly following an application. Currently labeled insecticides in grain sorghum are not adequate.  High rates of Lorsban (24-32 oz) appear to provide decent control but cannot be used for late-season infestations because of the 60 day preharvest application restriction.  Dimethoate, malathion and the 1-pint rate of chlorpyrifos provide only about 50% control.  Pyrethroid insecticides are not effective and may flare aphids.  If headworms occur, consider using Belt or Prevathon for control.  The states of Texas, Louisiana, Mississippi, Arkansas and Oklahoma have a Section 18 (emergency use exception) exception approval to use Transform WG (sulfoxaflor, Dow AgroSciences).  Studies in these states show an application of 1.0 – 1.5 oz per acre is about 90% effective, although aphids can build back in a few weeks. We are working on a section 18 emergency use exception request for Georgia, but Transform WG is currently not allowed in Georgia.”

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