Herbicide Use Conserves Water, Tripling Sorghum Yields


Sorghum Yield: Bushland, Texas

Sorghum is grown primarily in Great Plains states where it is used as a livestock feed. Early grain sorghum production generally involved clean tillage for weed control which eliminated most surface residues. When retained on the surface, crop residues increase soil water storage which increase crop yield. A USDA-ARS laboratory was established in Texas in 1938 and numerous tests have been conducted on ways of increasing sorghum yield in the very dry Texas climate. When herbicides became available and tillage was no longer required for weed control, more residues remained on the soil surface, more water was conserved and sorghum yields increased dramatically.

“In early dryland studies at the USDA laboratories in Bushland, Texas, USA, most residues were plowed under. Residue management for sorghum production received a major boost when improved herbicides and planting equipment became available in the 1960s. Retaining crop residues on the soil surface with no-tillage and improved herbicidal weed control are largely responsible for the increased water conservation achieved since the early 1970s. For 37 studies at the laboratory, preliminary analysis revealed that dryland sorghum grain yields more than tripled from 1939 to 1997. A major increase occurred in the early 1970s when using no-tillage became common. From 1939-1970, mean yield exceeded 2000 kg ha-1 only six times, but exceeded that amount 20 times after 1970.

Soil water content at planting was the dominant factor contributing to yield increases with time. Most increases in soil water content at planting occurred after the early 1970s, when improved herbicides became available and using conservation tillage (crop residue retention on the soil surface) received major emphasis at the laboratory.”

Authors: Unger, P. W., and R. L. Baumhardt.
Affiliation: USDA-ARS.
Title: Crop residue management increases dryland grain sorghum yields in a semiarid region.
Source: Sustaining the Global Farm. Selected Papers from the 10th International Soil Conservation Meeting held May 24-29, 1999. Pgs: 277-282.

The Sugarcane Aphid Makes a Mess on Sorghum

2 plants 1 picture

Sugarcane Aphid Damage to Sorghum

Grain sorghum is a billion dollar crop for Texas producers.  A 2013 outbreak of a new invasive pest (the “white” sugarcane aphid) caused from 25-50% loss in some unprotected fields. Infestations were very heavy, often with 100s of aphids per leaf. Leaves became sticky and shiny from aphid excreta and coated with sooty mold fungus, which hampered harvesting operations. Fortunately for 2014, an insecticide is available.

“Calling the current “white” sugarcane aphid outbreak in Deep South Texas a crisis, Texas AgriLife Extension Integrated Pest Management specialist Danielle Sekula-Ortiz is warning Lower Rio Grande Valley sorghum growers to “brace yourself” after scouting sorghum fields this week and warns about the proliferation of the pest in other types of crops.

“Practically overnight we saw a huge jump in aphid population numbers in sorghum fields across parts of the Valley and we are beginning to see movement between sorghum fields and corn and even sugarcane. I have never seen anything blossom this fast,” Sekula-Ortiz said.

Sekula-Ortiz has been warning sorghum growers to scout fields for the new sugarcane aphids, but she says many are still confused over the more traditional yellow sugarcane aphid and this new aphid species.

“Several growers have dealt with the larger yellow sugarcane aphid in the past and have not fully understood this new aphid represents a greater risk.

The good news, if there is any, is that early applications of Dow AgroSciences’ Transform WG are proving to be effective if applied correctly. The downside is an application increases input costs by about $6 an acre. EPA authorized a Section 18 to Texas Department of Agriculture for the use of Transform WG (sulfoxaflor) on sorghum to control the sugarcane aphid.

“We are looking at the need for two applications for adequate control, and maybe a third application depending on the intensity of the problem in individual fields.”

“Some of our larger producers in the Valley decided early on they wouldn’t treat their fields because of the added costs. Some felt like they had weathered past aphid outbreaks, but over the last week or so they are beginning to understand this is not just an average outbreak of the yellow sugarcane aphid but an entirely new threat.””

Author: Hawkes, L.
Affiliation: Reporter.
Title: “White” sugarcane aphid: “brace yourself” warns IPM specialist.
Source: Southwest Farm Press. 2014-05-20. Available: http://southwestfarmpress.com/grains/white-sugarcane-aphid-brace-yourself-warns-ipm-specialist

Rice Insect Pest Invades the World from the USA

Rice Water Weevil Larva

Rice Water Weevil Larva

The home of the rice water weevil is the southeastern US where the species feeds on
grasses in swampy areas. When rice plants were introduced into America, the
insect quickly found this new grass plant to its liking and has been feeding on
rice ever since. The weevils move into rice fields every year from nearby woods
and clumps of grass. Farmers have used insecticides since 1950 to control the
weevil populations in rice fields. The rice water weevil has spread from the
southeastern US to Louisiana, Texas, California, Japan, China and Italy where
it would decrease rice production without insecticide sprays.

“The rice water weevil, Lissorhoptrus oryzophilus, is the most destructive insect pest of rice in the United States. The insect is native to the southeastern United States but has, over the past 60 years, invaded important rice-growing areas in California, Asia and Europe and thus poses a global threat to rice production.

Small-plot research and sampling of commercial fields indicate yield losses from the rice water weevil would likely exceed 10% in many areas if no insecticides are used.”

Authors: Stout, M. J., et al.
Affiliations: Department of Entomology, Louisiana State University.
Title: The influence of rice plant age on susceptibility to the rice water weevil, Lissorhoptrus oryzophilus.
Source: Journal of Applied Entomology. 2013. 137:241-248.

Century-Old Cotton Rot Problem Solved with New Fungicide

Root Rot

Root Rot

Cotton Root Rot is a highly destructive disease caused by a soil borne fungus in the southwestern U.S. The fungus penetrates the roots of the cotton plant and blocks the flow of water from the roots to the leaves for transpiration, causing the leaves to wilt. Plants infected early in the growing season die before bearing fruit, whereas infections occurring at later plant growth stages reduce cotton yield and quality. Cotton Root Rot has plagued the cotton industry for more than 100 years. Despite decades of research, effective methods to control the disease were lacking until recently……

“On February 2, 2012, the US Environmental Protection Agency approved a section 18 label for Texas for the fungicide Topguard (flutriafol), to control root rot of cotton (CRR) caused by the soil borne fungus, Phymatotrichopsis omnivore.

CRR is the major yield-limiting disease in many of the cotton-production areas of Texas, causing annual losses exceeding $29 million. Yield losses to individual growers vary greatly, but can range up to 100%.

CRR has been a problem of Texas cotton since the 19th century. The first experiments on control of this disease were published in 1888 and in spite of extensive research efforts since then, there has been no substantial progress, until our recent identification of flutriafol as an effective fungicide. In some of our field trials with strong disease pressure, the yield was increased by as much as 60%. The application is made as a liquid spray to the soil around the seed at planting.”

Authors: Department of Plant & Microbiology Bioenvironmental Sciences
Affiliation: Texas A&M University
Title: Breakthrough against cotton root rot
Source: http://plantpathology.tamu.edu/breakthrough-against-cotton-root-rot/

Pecan Weevils Feast on Pecans in Orchards

Pecan Weevil Larva

Pecan Weevil Larva

Pecan Weevil Adult

Pecan Weevil Adult

The pecan weevil is a late season nut pest that feeds only on pecans and hickory. The female drills a hole in the nut with her snout and places one to four fertilized eggs within the kernel. The pecan weevil larvae are creamy, white legless grubs with soft fleshy bodies. Heavy populations of weevils can destroy all nuts on a tree.

“The pecan weevil is a major pest of pecans throughout the southeastern United States, as well as portions of Texas and Oklahoma. … Adults emerge from soil in late July-August to feed on and oviposit in developing nuts. Larval development is completed within the ripening kernel of the nut.”

“Current control recommendations for pecan weevil consist mainly of aboveground applications of chemical insecticides (e.g., carbaryl) to suppress adults. Application of chemical insecticides is recommended every 7-10 days during peak weevil emergence (generally up to at least a 6 week period).”

Authors: D.I. Shapiro-Ilan1, W.A. Gardner2, T.E. Cottrell1, R. W. Behle3 and B.W. Wood1

1USDA-ARS, Southeastern Fruit and Tree Nut Research Laboratoy, Byron, GA; 2Department of Entomology, University of Georgia, Griffin, GA; 3USDA-ARS-NCAUR, Peoria, IL
Title: Comparison of application methods for suppressing the pecan weevil (Coleoptera: Curculionidae) with Beauveria bassiana under field conditions.
Publication: Environmental Entomology. 2008. 37(1):162-171.

Organic Rice Growing Reduced Average Yield of Rice in Texas

Eight percent of the rice acreage in Texas is managed organically. These organic acres have much lower yields than conventionally grown acres. As a result, the overall yield of rice in Texas has declined.

“Organic rice acreage accounted for ca. 8% of the state’s total rice production. Organic rice fields typically yield ca. 30-40% of conventional commercial yields, this brought down the statewide average rice yields. An organic rice crop that yields 40% of the yield of a conventionally [grown] crop is equal to a 60% yield decrease. Multiplying a 60% yield decrease by 8% of the acreage is equal to a 5% drop in the average yield per acre.”

Author: L.T. Wilson
Affiliation: Texas A&M University
Title: From the Editor… Changes in Texas Rice Production
Publication: Texas Rice. 2007. Winter:2.