Weed control history

This book is about the revolutionary impact of the triazines herbicides, likely the most important class of agricultural chemicals ever developed. For five decades the triazines have provided weed control in more than 50 crops around the world and have helped farmers boost yields and produce enough food to feed a rising global population. The triazine herbicides, and especially atrazine, are the most well-researched herbicides in history, with thousands of scientific studies on their safety to humans and the environment. Data from studies on the triazines have been evaluated extensively by regulatory authorities around the globe to ensure their safe use. 

Shear, G. (1985). Introduction and history of limited-tillage. In A.F. Wiese, ed., Weed Control in Limited-Tillage Systems. Champaign, IL Weed Science Society of America, pp. 1-14. 

From the beginning of recorded history, weeds have limited man s food supply and have imposed a heavy labor burden. Nearly all of early man s time was no doubt spent in obtaining food. Natural food sources permitted man s survival, even though periods of starvation must have been common. From 10,000 B.C. to 6,000 B.C., man began to cultivate crops by primitive methods (Fig. 1) (JL). About 6,000 B.C., he fashioned hand-weeding tools. Around 1,000 B.C., animal-powered implements were introduced. Prior to this time, human energy was the sole source available for weed control. 

The impact of herbicides on our modern agricultural technology has been phenomenal. It is almost impossible to measure or to overemphasize the importance of herbicides in their potential for overcoming famine, pestilence, poverty and crop losses due to weeds that were prevalent throughout most of the history of mankind prior to the 1950s. Herbicides have been essential, not only for their direct effects on weed control and crop yield, but also in providing more efficient use of water and fertilizers for the optimum development of improved crop varieties and hybrids. They have also been essential tools in the recent development of conservation tillage methods, which have reduced topsoil erosion and moisture losses in many areas of the world. 

Between 1976 and 1978 Stauffer Chemical Company researchers identified fields where EPTC failed to give expected herbicidal activity. The fields had a history of repeated annual applications of EPTC. Greenhouse bioassays with EPTC demonstrated reduced persistence as the cause of reduced weed control observed in the field. Sterilization of the soil with heat or chemicals restored herbicidal activity. This indicated that, in some soils, enhanced microbial degradation might be associated with the observed reduction in herbicidal activity (D.L. Hyzak, personal communication). 

Reduced weed control with butylate in butylate history fields was reported in 1983 (7,8). Laboratory, greenhouse and field trials demonstrated that repeated annual use of butylate may cause enhanced butylate biodegradation and result in reduced weed control. Reports of reduced weed control with repeated use of butylate were much less frequent than with EPTC (Stauffer Chemical Company unpublished). Since 1986, the potential for enhanced biodegradation of butylate has been documented and described more completely by researchers in the Southeastern U.S. (9,10,11,12). 

Rotation with acetanilide herbicides for l year slightly increased the weed control. Two year rotations with acetanilides were as effective as cycloate in increasing the persistence of butylate and foxtail spp. control. It appeared that one annual application of cycloate or two annual applications of acetanilides eliminated enhanced biodegradation. Butylate residue data were not available from one year rotations with acetanilides or a non-history field to confirm the elimination of enhanced biodegradation (Table IV). 

Elimination or Inhibition of Enhanced Biodegradation by Herbicide Tank Mixtures. In one field trial, tank-mixes of atrazine with EPTC significantly increased green and yellow foxtail control at 60 DAT. In the green foxtail field, which had been treated with EPTC for 4 years, the application of EPTC provided little weed control. When EPTC was applied at 4.5 and 6.7 kg ai/ha tank-mixed with atrazine at 1.7 kg ai/ha, green foxtail control increased from 15 to 52% and from 22 to 94%, respectively. EPTC had only been applied once before to the yellow foxtail field. EPTC alone provided 68 to 72% control and tank-mixtures with atrazine provided 83 to 91% control, respectively (Table V). Atrazine tank-mixes appeared to be more beneficial In the field with the longer previous history of EPTC use. 

In another field trial, butylate and butylate tank-mixes were evaluated for weed control in a field with a 3 year history of... 

Weed Control and EPTC Persistence from EPTC + Dietholate + Atrazine in Rotation with Various Herbicides on a Silty Clay Loam Soil, Otoe, NE Field history of EPTC in 1982 and EPTC + dietholate in 1983 EPTC + dietholate broadcast applied at 4.5 kg/ha on 5/8/85... 

Herbicide Rate (kg/ha) Weed control Non-history 40 DAT History... 

Conclusion. In this chapter, we have attempted a broad overview of the biochemical and environmental properties of the sulfonylurea herbicides. The history of these herbicides is distinguished by the apparently endless variation in structure leading to new weed control spectra, crop selectivities and soil degradation properties. They have already achieved significant use in j ctice, and it is likely that Dr. Levitt s discovery will continue to yield new herbicide tools offering viable solutions to the needs of world agriculture and of society. 

Appleby AP (2005) A history of weed control in the United States and Canada - a sequel. Weed Sci 53 762-768... 

However, Arabian coffee is the great coffee of history and of commerce. It is the best liked and it is upon this species that the world largely depends. It is in large measure the coffee that has been given most careful scientific attention with respect to control of diseases, insects, and weeds. It is mostly from studies on this species that the information presented here comes. 

Ritter and Menbere (1997) have reviewed the history and control of triazine-resistant weeds - especially common lamb s-quarters, smooth pigweed, bamyardgrass, velvetleaf, and giant foxtail - in the mid-Atlantic region of the United States. They concluded that the factors influencing the presence of the resistant weeds included lack of crop rotation and lack of herbicide rotation. 

Throughout history, various types of pests, such as insects, weeds, bacteria, rodents, and other biological organisms, have bothered humans or threatened human health. People have been nsing pesticides for thousands of years to try to control these pests. The Snmerians used sulfur to control insects and mites 5,000 years ago. The Chinese used mercury and arsenic compotmds to control body lice and other pests. The Greeks and Romans used oil, ash, sulfur, and other materials to protect themselves, their hvestock, and their crops from various pests. And people in various cultures have used smoke, salt, spices, and insect-repelling plants to preserve food and keep pests away. 

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