In Italian rice fields in the 1950s prior to the development of herbicides, weeding was done by hand. In May, the rice fields had to be weeded to prevent the young rice from being choked by other vegetation. Hundreds of women known as le mondine, or weeders, arrived from all parts of Italy to perform the delicate task of rooting out the weeds while leaving the young rice plants in place. Le mondine have become a nostalgic memory, immortalized by the famous film Riso Amaro or ‘Bitter Rice.’ It was a hard life for le mondine. They had to work bent double, up to their knees in water under a blazing sun. As the women weeded, they sang. One of the songs, Bella Ciao, was adopted by the Italian Communist Party to express the social injustice of the system. In the 1960s, most of the women left the rice fields when jobs opened up in cities, such as Milan, Genoa, and Turin. Today, herbicides are used in Italian rice fields.
“Italy is the largest rice producer in Europe, with about 235,000 ha in 2012. The main rice cultivation area is concentrated in the north-western regions of Piedmont and Lombardy where the continuous paddy rice system is widespread. Weed management is one of the key aspects of rice cultivation because pedo-climatic conditions are favourable to weeds that are generally competitive, there is a rich and persistant seed bank, and the weed flora is often dominated by difficult-to-control species… Consequently, farmers need to apply complex chemical and agronomic strategies to guarantee good weed control. Herbicide use is intense, with an average treatment frequency index higher than 2.5.”
Authors: Scarabel, L, et al.
Affiliations: National Research Council, Italy.
Title: Resistance evolution and sustainability of the rice cropping system: the Italian case study.
Source: Global Herbicide Resistance Challenge: Program and Abstracts. February 18-22, 2013. Pg. 105.
For the past several years, Brazil has caught much of the attention of the global rice market. The large increase in rice production in Brazil, its expanding share in the international rice markets and its highly valued quality rice have made it recognized as a major player in the global rice market. Herbicides have played a major role in the increase in rice production in Brazil.
“Weedy red rice is one of the main problems in most of the rice-growing regions of the world because it decreases rice grain yield and milling quality. …The development of imidazolinone herbicide–resistant rice cultivars has allowed selective control of weedy red rice in the rice crop. This technology has been used across approximately 1.1 million ha in Brazil and the same area in the United States, and is under development in several countries in South and Central America, Central Europe, and Asia. The use of imidazolinone herbicides on imidazolinone-resistant rice cultivars has improved the control of red rice and led to the adoption of better crop management practices. In Brazil, this system started to be used in 2003, and since 2007 these processes resulted in an increase of approximately 40% in the mean rice grain yield in southern Brazil. Similar benefits have also been observed in other areas where this technology has been used.”
Authors: Goulart, C. G. R., et al.
Affiliations: Federal University of Rio Grande do Sul, Brazil.
Title: Distribution of weedy red rice (Oryza sativa) resistant to imidazolinone herbicides and its relationship to rice cultivars and wild Oryza species.
Source: Weed Science. 2014. 62:280-293. Available: http://www.bioone.org/doi/abs/10.1614/WS-D-13-00126.1
In Ghana, recent farmer surveys show that herbicide use by rice farmers is high. The adoption of herbicides is not due to programs being promoted by international organizations. Rather, the high adoption is simply due to farmers learning about the benefits of herbicides from other farmers.
“There was strikingly high use of herbicide in rice plots, with 84 percent of rice area treated with herbicide across all rice ecologies. Fifty-eight percent of rice area was treated with herbicide before planting, and 69 percent of the area was treated with herbicide after planting.
The yield of plots with herbicide is significantly higher than that of plots without herbicide for all rice ecologies…. For irrigated plots with fertilizer and certified seed, there was a 3.1 ton/hectare difference between plots with and without herbicide.
A simple comparison of weeding costs suggests that farmers using herbicide spend 666 cedi/hectare total in purchasing herbicide (8 liters at 8 cedi/liter) and an additional 86 person-days for manual weeding, while farmers not using herbicide spend 1,477 cedi/hectare for manual weeding for 211 person-days on average. It is apparent from this calculation that it is cheaper to purchase herbicide than to hire or use family labor for weeding.
The diffusion of herbicide seems to be wide, and farmers are learning about it from other farmers. About half of farmers reported that they knew about herbicide and its benefits from advice by or observing other farmers’ plots. …This suggests that if a technology is beneficial, it can spread quickly among farmers.”
The India herbicide market is experiencing a growth spurt of epic proportions- growing by 35% in 2012. The increased use of herbicides in India is being spurred on by the lack of labor for hand weeding. The younger generation is losing interest in farming due to the availability of higher paying jobs in the fast growing industrial, business and construction sectors. Research by Indian agronomists backs up the positive contribution that herbicides make in terms of labor use, yield and profits.
“The objective of this study was to compare the profitability of farms that are using herbicides as one of their control measures and otherwise… For farms using herbicides, the analysis showed that labour usage was about 43, 33 and 80 hours lower in paddy rice, maize and sugarcane crops, respectively. Yields in farms using herbicides were also higher by about nine quintals in paddy rice, four quintals in maize and 100 quintals in sugarcane. Profits were also higher where herbicides were applied. It was concluded that application of herbicides to control weeds in paddy rice, maize and sugarcane is an efficient way of weed control in terms of labour use, yield and profits.”
Authors: Govindarajan, K., et al.
Affiliation: Tamil Nadu Agricultural University
Title: Impact analysis of integrated weed management under irrigated eco-systems in cultivation of tropical crops in Tamil Nadu, Southern India.
Source: 2nd International Conference on Novel and sustainable weed management in arid and semi-arid agro-ecosystems. September 7-10, 2009. Agricultural University of Athens
Sheath blight is a disease of rice plants which is caused by a fungus that lives in the soil. When rice fields are flooded, the fungus floats to the top of the water and contacts rice plants; the fungus grows out and moves into the rice leaf. The fungus spreads across the water to adjacent plants. The fungus grows across touching plant parts. The flow of water and nutrients in the rice plant is interrupted and the leaf dies, reducing rice yield. Development of resistant cultivars has been slow, because resistance is linked to undesirable traits such as tall plant stature, late maturity, and poor milling quality. Research has shown that a single application of a fungicide provides almost season-long control of sheath blight.
“Sheath blight of rice, caused by the fungus Rhizoctonia solani, is an economically important rice disease that is occurring throughout the rice-producing areas in the world, including the southern United States. Significant losses in grain quality and yield may occur in severely infected rice fields. Despite its economic importance, there are no completely resistant rice cultivars against this fungal rice disease and control methods for sheath blight are limited to heavy usage of fungicides.”
Authors: Shrestha, B. K., et al. Affiliation: Louisiana State University Agricultural Center, Baton Rouge Title: Suppression of sheath blight development in rice and sclerotia germination of Rhizoctonia solani by rice-associated strains of Bacillus spp. Source: Phytopathology. 2013. 103(Supplement 1)(5):S1.9
In 2001, herbicide use began to increase in Finland largely due to government policies subsidizing growers to no longer plow fields for weed control. Finland is a signatory to the North Sea Treaty which includes a goal of reducing nutrients into the North Sea by half. Research showed that a considerable amount of phosphorus moves into waterways with eroded soils from fields that are plowed in the autumn. Thus, growers now are using herbicides to control weeds without plowing in order to keep phosphorus out of the North Sea.
“Our weed survey represented part of a follow-up project on the impacts of agri-environment policy in Finland. For instance, reduced tillage has been one of the subsidized measures primarily implemented to reduce nutrient leaching. Spring cereals, 1.1 million hectares in total, covering 50-55% of arable land, dominate crop production in Finland. In the 1990s ploughing was still the standard tillage practice in spring cereal fields, while the latest statistics show that only approximately half of the cultivated cereal field area is currently ploughed. Ploughing has been replaced with reduced tillage methods (29%) or direct drilling (17%). At the same time, the sales of glyphosate have more than doubled within a decade in Finland.
Increased use of glyphosate in Finland is notable; in 1999, the annual sales of glyphosate products were sufficient to treat about 13% of arable land under cultivation or fallow, while the same figure had increased to 37% in 2010.”
Author(s): Salonen, J., et al.
Affiliation: MTT Agrifood Research Finland, Plant Production Research, Jokionen, Finland
Title: Impact of changed cropping practices on weed occurrence in spring cereals in Finland – a comparison of surveys in 1997-1999 and 2007-2009.
Source: Weed Research. 53:110-120. 2012.
Insects often transmit diseases when they fed on a crop plant. Rice is fed on by planthoppers which transmit viruses. In one outbreak in China, 30 million planthoppers were estimated to infest each of 50 million acres. Major losses were prevented thanks to insecticide sprays.
“Laodelphax striatellus Fallén (Hemoptera: Delphacidae) is an economically important sap-sucking pest in rice. The leaves infested by L. striatellus turn yellow, wilt, and even die, resulting in yield loss and quality reduction. In addition, L. striatellus transmits rice viral diseases such as Rice black-streaked dwarf virus and Rice stripe virus, which are two of the most serious diseases and often cause major yield losses. In recent years, the damage caused by L. striatellus feeding injury and the diseases transmitted by this planthopper has been increasing in China. When the outbreak occurred in Jiangsu and Anhui provinces in 2004 and 2005, the density of L. striatellus reached 30 million per acre, and 50 million acres of rice was infested, causing 30% of yield reduction in areas without pesticide treatment.”
Authors: C-X Duan1, J-M Wan1, H-Q Zhai2, Q Chen1, J-K Wang1, N Su1 and C-L Lei1
Affiliation: 1Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China; 2Chinese Academy of Agricultural Sciences, Beijing, China
Title: Quantitative trait loci mapping of resistance to Laodelphax striatellus (Hemoptera: Delphacidae) in rice using recombinant inbred lines.
Publication: Journal of Economic Entomology. 2007. 100(4):1450-1455.
The feeding of rice bugs on rice plants results in black marks on the rice grains. Japanese consumers demand perfect rice, which means that farmers must prevent the insects from feeding.
“A complex of Hemiptera, commonly referred to as rice bugs, are considered to be important insect pests in rice-growing regions of the world. Many species of Hemiptera, from families including Alydidae, Pentatomidae, Coreidae, and Miridae, have been reported as rice bugs.”
“Rice bugs cause yield loss, decrease the quality of grain, and reduce the germination rate. Among these problems, decrease in the quality of grain is considered to be the most important problem in Japanese rice. Infestations cause brown or black marks on the grain. Contamination of as little as 0.1% of such stained grain has reduced commercial value according to Japanese rice quality regulations, and thus the economic injury level is very low. This has led rice farmers to a dependence on insecticide use for rice bug control.”
Authors: H. Takeuchi1,2 and T. Watanabe1
Affiliation: 1Department of Entomology and Nematology, National Agricultural Research Center, Tsukuba, Japan; 2National Agricultural Research Center for Kyushu Okinawa Region, Kumamoto, Japan.
Title: Mortality factors of eggs of Leptocorisa chinensis (Hemiptera: Alydidae) in rice fields.
Publication: Journal of Economic Entomology. 2006. 99(2):366-372.
Over the past several decades, China has become self-sufficient in basic foods such as wheat, maize, and rice. In addition, Chinese production of many fruit and vegetable crops has soared. The widespread use of pesticides has had a key role in this vast expansion in food production and without their use…
“China would ‘undergo famine if pesticides were not used’. The warning has come in a recent Ministry of Agriculture document entitled ‘pesticide residues in agricultural products and related safety issues’, reports the national newspaper, the AgriGoods Herald.”
“China has more than 1,700 types of plant disease and insect pests, with major pest outbreaks occurring on over 400 million hectares annually. Laboratory findings released by Chinese agrochemical company Beijing Yoloo Pesticide showed that rice production would be reduced by more than two-thirds if pesticides were not used, and wheat production would be halved.”
Authors: Agrow staff writer
Headline: China warns of famine without pesticides.
Publication: Agrow. 2012. No. 642, June 20.
Wild rice originated in Minnesota and the surrounding Great Lakes. It is the only cereal native to North America that has been domesticated from a wild plant. Before commercial production began, wild rice was difficult to obtain. The first commercial field of wild rice was planted in 1950 in Minnesota. After one season, fungal brown spot disease destroyed the second crop. In the next decade, fungal brown spot destroyed much of Minnesota’s wild rice crops – epidemics in 1973 and 1974 resulted in complete crop loss in many paddies. Ever since 1974 Minnesota growers have sprayed fungicides in order to produce commercial wild rice.
“Propiconazole, a systemic ergosterol biosynthesis-inhibiting fungicide, was evaluated for FBS control during 1985-1987 at the University of Minnesota North Central Experiment Station in Grand Rapids. In 1985 and 1986, propiconazole applications at both boot and heading stages of development increased yield by 68 and 40%, respectively, and in 1987 applications increased yield 113%.”
“Registration of propiconozale is crucial, because commercial wild rice production in Minnesota without fungicides may not be economically feasible.”
Author: D.R. Johnson and J.A. Percich
Affiliation: University of Minnesota, St. Paul
Title: Wild rice domestication, fungal brown spot disease, and the future of commercial production in Minnesota.
Publication: Plant Disease. 1992. December:1193-1198.