Plan for strong disease, nematode pressure early this year

Author: Bob Kemerait, UGA Extension Plant Pathologist

We are well into one of my favorite times of the year, the “winter meeting season.” From January through the middle of April, my fellow Extension specialists and I travel the highways giving updates on crop production for 2017. 

At the invitation of county agents, I often spend morning, noon and night sharing recommendations for disease and nematode management in cotton, peanuts, corn and soybeans. Some have referred to our travels as “the Bar-B-Que Trail” as such is frequently served during our sponsored meals. We still eat plenty of bar-b-que; however we are also treated to favorites ranging from eggs, bacon and grits to fried fish, fried quail, smoked pork chops and banana pudding.  It’s tough to be a vegetarian, or diet, on the Bar-B-Que Trail.

I hope that farmers walk away from these meetings with information they can use successfully.  With two or three Extension specialists speaking, it is easy to overload the audience with too many "just one more thing before I finish up..." comments. I do my best to emulate my boyhood hero, Sergeant Joe Friday from "Dragnet," who is remembered for the quote, "Just the facts ma'am, just the facts." 

Facts for 2017 crop production:

The Deep South is experiencing a weak La Niña this winter and one characteristic of such is warmer-than-normal temperatures.  This is not to say that we won’t have colder weather, but overall the trend has been for unusually warm days, delayed frost and extended survival of “volunteer” peanuts, corn, and re-growth cotton.  The take-home message is that unusually warm weather can have a significant impact on diseases and nematodes in the upcoming season and growers should be prepared. 

Whether it is the impact on thrips and tomato spotted wilt, nematodes waking up hungry and early due to warm soils or white mold aggressively attacking young peanut plants, conditions likely to occur during a La Niña winter can affect risk to diseases and nematodes.  As the saying goes, “forewarned is forearmed.”

Variety selection plays an important part in a disease and nematode management program.  Growers may choose “yield advantage” over all else, but they should be aware of available disease and nematode resistant varieties.  Corn growers should consider varieties with resistance to diseases like northern and southern corn leaf blights, gray leaf spot, and Fusarium and Diplodia ear rots. 

Soybean producers should consider varieties with resistance to nematodes a number of diseases, to include frogeye leaf spot and anthracnose. 

Cotton growers need to consider not only resistance to southern root-know nematodes, as found in ST 4946 GLB2, DP 1558 NR B2RF and PHY 487 WRF, but also varieties with resistance to bacterial blight.  Unfortunately, our “root-knot-nematode-resistant” cotton varieties are not resistant to bacterial blight, but there are other varieties that have at least partial resistance.  These varieties include ST 5115 GLT, NG 5007 B2XF, PHY 339 WRF, PHY 444 WRF, PHY 490 W3FE, PHY 575 WRF, DP 1518 B2XF DP 1639 B2XF and DP 1646 B2XF. 

Peanut growers should consult the 2017 Peanut Rx risk index to determine varieties with increased resistance to tomato spotted wilt, stem rot (white mold) and leaf spot.  Where peanut root-knot nematodes affect a crop, growers can plant highly resistant ‘Georgia-14N’ and ‘TifGuard’ varieties.

Fungicides and nematicides

There is much to discuss about fungicides and nematicides for 2017.  Telone II, a soil fumigant for management of plant-parasitic nematodes, is reported to be in short supply in 2017.  Growers wanting to use Telone II should move quickly to secure needed quantities.  All Stoneville cotton seed in 2017 will be pre-treated with COPeO Prime, a new seed treatment nematicide from Bayer CropScience that contains fluopyram, the same active as in Velum Total.  COPeO Prime will also be available on Fiber Max seed as a “premium” elective treatment.  AgLogic 15G, a new formulation of aldicarb, will be available for use on cotton, peanuts, soybeans and other crops.  AgLogic 15G is used for management of thrips and plant-parasitic nematodes.  Beginning in 2017, AgLogic will be produced on in the “gypsum” formulation. 

Growers who use Velum Total for management of nematodes on peanut may want to consider a “pegging time” application of Propulse for additional control.  Propulse from Bayer CropScience is a combination of fluopyram and prothioconazole.  It is useful in the management of nematodes, white mold (stem rot) and leaf spot.

Elatus and Priaxor, premixes of strobilurin and SDHI fungicides, are effective products for reducing resistance issues with strobilurin fungicides used alone in peanut. 

Provost, well-known for use on peanuts, has been replaced with a new “Provost Opti” product.  Provost Opti is reformulated to eliminate tanx-mix compatibility issues.  Sipacm Agro now offers fungicides Mazinga (chorothalonil and tetraconazole) and ARIUS ADV (azoxystrobin and chlorothalonil) for disease management in peanut.  Zolera FX (fluoxastrobin + tetraconzole) from ARYSTA LIFESCIENCE and Affiance (azoxystrobin + tetraconazole) from GOWAN are new fungicide for corn and soybeans.

The notes here are but a few of the high-points for 2017.  I strongly encourage participation in production meetings this winter where topics will be discussed in greater detail and important questions can be answered.  “Just the facts” was enough for Sergeant Joe Friday, but sometimes we need Paul Harvey and “the rest of the story,” too!

Source: Southeast Farm Press