Precision Agriculture: Advantages and Disadvantages

Precision Agriculture: Advantages and Disadvantages Precision agriculture Precision farming or precision agriculture is an agricultural concept relying on the existence of in-field variability. It requires the use of new technologies, such as global positioning (GPS), sensors, satellites or aerial images, and information management tools (GIS) to assess and understand variations. Collected information may be used to more precisely evaluate optimum sowing density, estimate fertilizers and other inputs needs, and to more accurately predict crop yields. It seeks to avoid applying inflexible practices to a crop, regardless of local soil/climate conditions, and may help to better assess local situations of disease or lodging. Satellites allow farmers to easily survey their land.[2] Global Positioning Systems (GPS) monitor can find the location of a field to within one meter. It can then present a series of GIS maps that demonstrate which fields are moist or dry, and where there is erosion of soil and other soil factors that stunt crop growth. The data can be used by the farmer to automatically regulate the machine application of fertilizer and pesticide[2]. In the American Midwest (US) it is associated not with sustainable agriculture but with mainstream farmers who are trying to maximize profits by spending money only in areas that need fertilizer. This practice allows the farmer to vary the rate of fertilizer across the field according to the need identified by GPS guided Grid Sampling. Fertilizer that would have been spread in areas that dont need it can be placed in areas that do, thereby optimizing its use. Precision farming may be used to improve a field or a farm management from several perspectives: agronomical perspective: adjustment of cultural practices to take into account the real needs of the crop (e.g., better fertilization management) technical perspective: better time management at the farm level (e.g. planning of agricultural activity) environmental perspective: reduction of agricultural impacts (better estimation of crop nitrogen needs implying limitation of nitrogen run-off) economical perspective: increase of the output and/or reduction of the input, increase of efficiency (e.g., lower cost of nitrogen fertilization practice) Other benefits for the farmer geostatistics integrated farming Integrated Pest Management nutrient budgeting nutrient management precision viticulture Agriculture Landsat program Geostatistics is a branch of statistics focusing on spatiotemporal datasets. Developed originally to predict probable distributions for mining operations, it is currently applied in diverse disciplines including petroleum geology, hydrogeology, hydrology, meteorology, oceanography, geochemistry, geometallurgy, geography, forestry, environmental control, landscape ecology, soil science, and agriculture (esp. in precision farming). Geostatistics is applied in varied branches of geography, particularly those involving the spread of disease (epidemiology), the practice of commerce and military planning (logistics), and the development of efficient spatial networks. Geostatistics are incorporated in tools such as geographic information systems (GIS) and digital elevation models. History This section requires expansion with: details. Background When any phenomena is measured, the observation methodology will dictate the accuracy of subsequent analysis; in geography, this issue is complicated by unique variables and spatial patterns such as geospatial topology. An interesting feature in geostatistics is that every location displays some form of spatial pattern, whether in the form of the environment, climate, pollution, urbanization or human health. This is not to state that all variables are spatially dependent, simply that variables are incapable of measurement separate from their surroundings, such that there can be no perfect control population. Whether the study is concerned with the nature of traffic patterns in an urban core, or with the analysis of weather patterns over the Pacific, there are always variables which escape measurement; this is determined directly by the scale and distribution of the data collection, or survey, and its methodology. Limitations in data collection make it impossible to make a direct meas ure of continuous spatial data without inferring probabilities, some of these probability functions are applied to create an interpolation surface predicting unmeasured variables at innumerable locations. Geostatistical terms Regionalized variable theory Covariance function Semi-variance Variogram Kriging Range (geostatistics) Sill (geostatistics) Nugget effect Criticism A major contributor to this section (or its creator) appears to have a conflict of interest with its subject. It may require cleanup to comply with Wikipedias content policies, particularly neutral point of view. Please discuss further on the talk page. ({{{November 2009}}}) Jan W Merks, a mineral sampling expert consultant from Canada, has strongly criticized[1] geostatistics since 1992. Referring to it as voodoo science[2] and scientific fraud, he claims that geostatistics is an invalid branch of statistics. Merks submits[2] that geostatistics ignores the variance of Agterbergs distance-weighted average point grade, ignores the concept of degrees of freedom of a data set when testing for spatial dependence by applying Fishers F-test to the variance of a set and the first variance term of the ordered set, abuses statistics by not using analysis of variance properly, replaced genuine variances of single distance-weighted average point grades with pseudo-variances of sets of distance-weighted average point grades, violating the one-to-one correspondence between variances and functions such as Agterbergs distance-weighted average point grade. Furthermore, Merks claims geostatistics inflates mineral reserve and resources such as in the case of Bre-Xs fraud. Merkss expertise and credibility are supported by several company executives, who regularly hire his consulting services[3]. Philip and Watson have also criticized geostatistics in the past [4]. There is a consensus that inappropriate use of geostatistics makes the method susceptible to erroneous reading of results[3][5]. Related software gslib is a set of fortran 77 routines (open source) implementing most of the classical geostatistics estimation and simulation algorithms sgems is a cross-platform (windows, unix), open-source software that implements most of the classical geostatistics algorithms (kriging, Gaussian and indicator simulation, etc) as well as new developments (multiple-points geostatistics). It also provides an interactive 3D visualization and offers the scripting capabilities of python. gstat is an open source computer code for multivariable geostatistical modelling, prediction and simulation. The gstat functionality is also available as an S extension, either as R package or S-Plus library. besides gstat, R has at least six other packages dedicated to geostatistics and other areas in spatial statistics. Notes 1. ^ A website that criticizes Matheronian geostatistics ^ a b See (Merks 1992) 3. ^ a b Sandra Rubin, Whistleblower raises doubts over ore bodies, Financial Post, September 30, 2002. ^ See (Philip and Watson 1986). 5. ^ Statistics for Spatial Data, Revised Edition, Noel A. C. Cressie, ISBN 978-0-471-00255-0. References 1. Armstrong, M and Champigny, N, 1988, A Study on Kriging Small Blocks, CIM Bulletin, Vol 82, No 923  Armstrong, M, 1992, Freedom of Speech? De Geeostatisticis, July, No 14 3. Champigny, N, 1992, Geostatistics: A tool that works, The Northern Miner, May 18 4. Clark I, 1979, Practical Geostatistics, Applied Science Publishers, London 5. David, M, 1977, Geostatistical Ore Reserve Estimation, Elsevier Scientific Publishing Company, Amsterdam 6. Hald, A, 1952, Statistical Theory with Engineering Applications, John Wiley Sons, New York 7. Chilà ¨s, J.P., Delfiner, P. 1999. Geostatistics: modelling spatial uncertainty, Wiley Series in Probability and Mathematical Statistics, 695 pp. 8. Deutsch, C.V., Journel, A.G, 1997. GSLIB: Geostatistical Software Library and Users Guide (Applied Geostatistics Series), Second Edition, Oxford University Press, 369 pp., http://www.gslib.com/ 9. Deutsch, C.V., 2002. Geostatistical Reservoir Modeling, Oxford University Press, 384 pp., http://www.statios.com/WinGslib/index.html 10. Isaaks, E.H., Srivastava R.M.: Applied Geostatistics. 1989. 11. ISO/DIS 11648-1 Statistical aspects of sampling from bulk materials-Part1: General principles 12. Journel, A G and Huijbregts, 1978, Mining Geostatistics, Academic Press 13:.Kitanidis, P.K.: Introduction to Geostatistics: Applications in Hydrogeology, Cambridge University Press. 1997. 14. Lantuà ©joul, C. 2002. Geostatistical simulation: models and algorithms. Springer, 256 pp. 15. Lipschutz, S, 1968, Theory and Problems of Probability, McCraw-Hill Book Company, New York. 16. Matheron, G. 1962. Traità © de gà ©ostatistique appliquà ©e. Tome 1, Editions Technip, Paris, 334 pp. 17. Matheron, G. 1989. Estimating and choosing, Springer-Verlag, Berlin. 18. McGrew, J. Chapman, Monroe, Charles B., 2000. An introduction to statistical problem solving in geography, second edition, McGraw-Hill, New York. 19. Merks, J W, 1992, Geostatistics or voodoo science, The Northern Miner, May 18 20. Merks, J W, Abuse of statistics, CIM Bulletin, January 1993, Vol 86, No 966 21. Myers, Donald E.; What Is Geostatistics? 22. Philip, G M and Watson, D F, 1986, Matheronian Geostatistics; Quo Vadis?, Mathematical Geology, Vol 18, No 1 23. Sharov, A: Quantitative Population Ecology, 1996, http://www.ento.vt.edu/~sharov/PopEcol/popecol.html 24. Shine, J.A., Wakefield, G.I.: A comparison of supervised imagery classification using analyst-chosen and geostatistically-chosen training sets, 1999, http://www.geovista.psu.edu/sites/geocomp99/Gc99/044/gc_044.htm 25. Strahler, A. H., and Strahler A., 2006, Introducing Physical Geography, 4th Ed., Wiley. 26. Volk, W, 1980, Applied Statistics for Engineers, Krieger Publishing Company, Huntington, New York. 27. Wackernagel, H. 2003. Multivariate geostatistics, Third edition, Springer-Verlag, Berlin, 387 pp. 28. Yang, X. S., 2009, Introductory Mathematics for Earth Scientists, Dunedin Academic Press, 240pp. 29. Youden, W J, 1951, Statistical Methods for Chemists: John Wiley Sons, New York. External links Kriging link, contains explanations of variance in geostats Arizona university geostats page A resource on the internet about geostatistics and spatial statistics On-Line Library that chronicles Matherons journey from classical statistics to the new science of geostatistics Retrieved from http://en.wikipedia.org/wiki/Geostatistics Categories: Geostatistics Hidden categories: Statistics articles needing expert attention | Articles needing expert attention from August 2009 | All articles needing expert attention | Articles lacking in-text citations from January 2009 | All articles lacking in-text citations | Articles to be expanded from January 2010 | All articles to be expanded | Wikipedia expand-section box with explanation text | Articles to be expanded from August 2008 | Wikipedia articles with sections containing possible conflicts of interest Integrated farming (or integrated agriculture) is a commonly and broadly used word to explain a more integrated approach to farming as compared to existing monoculture approaches. It refers to agricultural systems that integrate livestock and crop production and may sometimes be known as Integrated Biosystems. While not often considered as part of the permaculture movement Integrated Farming is a similar whole systems approach to agriculture[1]. There have been efforts to link the two together such as at the 2007 International Permaculture Conference in Brazil[2]. Agro-ecology (which was developed at University of California Santa Cruz) and Bio-dynamic farming also describe similar integrated approaches. Examples include: pig tractor systems where the animals are confined in crop fields well prior to planting and plow the field by digging for roots poultry used in orchards or vineyards after harvest to clear rotten fruit and weeds while fertilizing the soil cattle or other livestock allowed to graze cover crops between crops on farms that contain both cropland and pasture (or where transhumance is employed) Water based agricultural systems that provide way for effective and efficient recycling of farm nutrients producing fuel, fertilizer and a compost tea/mineralized irrigation water in the process. In 1993 FARRE (Forum de lAgriculture Raisonnà ©e Respecteuse lEnvironnement) developed agricultural techniques France as part of an attempt to reconcile agricultural methods with the principles of sustainable development. FARRE, promotes an integrated and/or multi-sector approach to food production that includes profitability, safety, animal welfare, social responsibility and environmental care. Zero Emissions Research and Initiatives (formed in 1994 by the eco-entrepreneur [1]) developed a similar approach to FARRE seeking to promote agricultural and industrial production models that sought to incorporate natures wisdom into the process. ZERI helped support an effort by an environmental engineer from Mauritius named George Chan. Chan working with a network of poly-culture farming pioneers began refining Integrated Farming practices that had already been developed in south-east Asia in the 60,70s and 80s, building on the ancient Night soil farming practice. In China, programs embracing this form of integrated farming have been successful in demonstrating how an intensive growing systems can use organic and sustainable farming practices, while providing a high agriculture yield. Taking what he learned from the Chinese during his time there, Chan worked at the UN University in the 1990s and forwarded an approach to Integrated Farming which was termed Integrated Biomass Systems working specifically under the UNU/ZERI ZERI Bag Program. Chan during his work with UNU sought to make the case that Integrated Biomass Systems were well suited to help small island nations and low lying tropical regions become more self-reliant and prosperous in the production of food[3]. Working with ZERI, he developed several prototypes for this approach around the world including sites in Namibia and Fiji. The scientifically verified results in a UNDP sponsored congress in 1997 resulted in the adoption of the IBS by the State Government of Paranà ¡, Brazil where dozens of piggeries have applied the system generating food, energy while improving health and environmental conditions. Montfort Boys Town in Fiji was one of the first Integrated Biomass Systems developed outside of Southeast Asia with the support of UNU, UNDP and other international agencies. The project which is still operational continues to be a model of how farm operations can provide multiple benefits to stakeholders both local and international. ZERI Bag had a significant African component that included assisting Father Godfrey Nzamujo in the development of the Songhai Farm Integrated Farming project in Benin[4] . Most recently The Heifer Foundation a major international NGO based in the USA has taken a lead role in deploying Integrated Farming so that it can be replicated globally as an effective approach to sustainable farming in non-affluent regions such as Vietnam[5]. References 1. ^ Steve Divers work linking Integrated Farming with Permaculture: http://attra.ncat.org/attra-pub/perma.html 2. ^ Report includes reference to presentation on Integrated Farming by permaculture and ZERI practitioner Eric Fedus and Alexandre Takamatsu 3. ^ Small Islands and ZERI: A unique case for the Application of ZERI: A Paper presented by George Chan of the United Nations University at an International Symposium on Small Islands and Sustainable Development organized by the United Nations University and the National Land Agency of Japan: http://www.gdrc.org/oceans/chan.html 4. ^ ZERI Bag was designed to focus on small scale deployment of appropriate technologies with a focus on the Integrated Biomass System approach developed by ZERI and George Chan http://www.zeri.unam.na/africa.htm 5. ^ http://www.heifer.org/site/c.edJRKQNiFiG/b.2877337/ External links FARRE homepage Integrated farming of fish, crop and livestock Design an construction of an intergated fish farm Integrated Farming System by George Chan wiki on integrated farming Songhai Centre in Benin IPM: In agriculture, integrated pest management (IPM) is a pest control strategy that uses a variety of complementary strategies including: mechanical devices, physical devices, genetic, biological, cultural management, and chemical management. These methods are done in three stages: prevention, observation, and intervention. It is an ecological approach with a main goal of significantly reducing or eliminating the use of pesticides while at the same time managing pest populations at an acceptable level.[1] For their leadership in developing and spreading IPM worldwide, Dr. Perry Adkisson and Dr. Ray F. Smith received the 1997 World Food Prize. History of IPM Shortly after World War II, when synthetic insecticides became widely available, entomologists in California developed the concept of supervised insect control. Around the same time, entomologists in cotton-belt states such as Arkansas were advocating a similar approach. Under this scheme, insect control was supervised by qualified entomologists, and insecticide applications were based on conclusions reached from periodic monitoring of pest and natural-enemy populations. This was viewed as an alternative to calendar-based insecticide programs. Supervised control was based on a sound knowledge of the ecology and analysis of projected trends in pest and natural-enemy populations. Supervised control formed much of the conceptual basis for the integrated control that University of California entomologists articulated in the 1950s. Integrated control sought to identify the best mix of chemical and biological controls for a given insect pest. Chemical insecticides were to be used in manner least disruptive to biological control. The term integrated was thus synonymous with compatible. Chemical controls were to be applied only after regular monitoring indicated that a pest population had reached a level (the economic threshold) that required treatment to prevent the population from reaching a level (the economic injury level) at which economic losses would exceed the cost of the artificial control measures. IPM extended the concept of integrated control to all classes of pests and was expanded to include tactics other than just chemical and biological controls. Artificial controls such as pesticides were to be applied as in integrated control, but these now had to be compatible with control tactics for all classes of pests. Other tactics, such as host-plant resistance and cultural manipulations, became part of the IPM arsenal. IPM added the multidisciplinary element, involving entomologists, plant pathologists, nematologists, and weed scientists. In the United States, IPM was formulated into national policy in February 1972 when President Nixon directed federal agencies to take steps to advance the concept and application of IPM in all relevant sectors. In 1979, President Carter established an interagency IPM Coordinating Committee to ensure development and implementation of IPM practices. (references: The History of IPM, BioControl Reference Center. [1] How IPM works An IPM regime can be quite simple or sophisticated. Historically, the main focus of IPM programs was on agricultural insect pests.[2] Although originally developed for agricultural pest management, IPM programs are now developed to encompass diseases, weeds, and other pests that interfere with the management objectives of sites such as residential and commercial structures, lawn and turf areas, and home and community gardens. An IPM system is designed around six basic components: The US Environmental Protection Agency has a useful set of IPM principles. [2] 1. Acceptable pest levels: The emphasis is on control, not eradication. IPM holds that wiping out an entire pest population is often impossible, and the attempt can be more costly, environmentally unsafe, and frequently unachievable. IPM programs first work to establish acceptable pest levels, called action thresholds, and apply controls if those thresholds are crossed. These thresholds are pest and site specific, meaning that it may be acceptable at one site to have a weed such as white clover, but at another site it may not be acceptable. This stops the pest gaining resistance to chemicals produced by the plant or applied to the crops. If many of the pests are killed then any that have resistance to the chemical will rapidly reproduce forming a resistant population. By not killing all the pests there are some un-resistant pests left that will dilute any resistant genes that appear. 2. Preventive cultural practices: Selecting varieties best for local growing conditions, and maintaining healthy crops, is the first line of defense, together with plant quarantine and cultural techniques such as crop sanitation (e.g. removal of diseased plants to prevent spread of infection). 3. Monitoring: Regular observation is the cornerstone of IPM. Observation is broken into two steps, first; inspection and second; identification.[3] Visual inspection, insect and spore traps, and other measurement methods and monitoring tools are used to monitor pest levels. Accurate pest identification is critical to a successful IPM program. Record-keeping is essential, as is a thorough knowledge of the behavior and reproductive cycles of target pests. Since insects are cold-blooded, their physical development is dependent on the temperature of their environment. Many insects have had their development cycles modeled in terms of degree days. Monitor the degree days of an environment to determine when is the optimal time for a specific insects outbreak. 4. Mechanical controls: Should a pest reach an unacceptable level, mechanical methods are the first options to consider. They include simple hand-picking, erecting insect barriers, using traps, vacuuming, and tillage to disrupt breeding. 5. Biological controls: Natural biological processes and materials can provide control, with minimal environmental impact, and often at low cost. The main focus here is on promoting beneficial insects that eat target pests. Biological insecticides, derived from naturally occurring microorganisms (e.g.: Bt, entomopathogenic fungi and entomopathogenic nematodes), also fit in this category. 6. Chemical controls: Synthetic pesticides are generally only used as required and often only at specific times in a pests life cycle. Many of the newer pesticide groups are derived from plants or naturally occurring substances (e.g.: nicotine, pyrethrum and insect juvenile hormone analogues), and further biology-based or ecological techniques are under evaluation. IPM is applicable to all types of agriculture and sites such as residential and commercial structures, lawn and turf areas, and home and community gardens. Reliance on knowledge, experience, observation, and integration of multiple techniques makes IPM a perfect fit for organic farming (the synthetic chemical option is simply not considered). For large-scale, chemical-based farms, IPM can reduce human and environmental exposure to hazardous chemicals, and potentially lower overall costs of pesticide application material and labor. 1. Proper identification of pest What is it? Cases of mistaken identity may result in ineffective actions. If plant damage due to over-watering are mistaken for a fungal infection, a spray may be used needlessly and the plant still dies. 2. Learn pest and host life cycle and biology. At the time you see a pest, it may be too late to do much about it except maybe spray with a pesticide. Often, there is another stage of the life cycle that is susceptible to preventative actions. For example, weeds reproducing from last years seed can be prevented with mulches. Also, learning what a pest needs to survive allows you to remove these. 3. Monitor or sample environment for pest population How many are here? Preventative actions must be taken at the correct time if they are to be effective. For this reason, once you have correctly identified the pest, you begin monitoring BEFORE it becomes a problem. For example, in school cafeterias where roaches may be expected to appear, sticky traps are set out before school starts. Traps are checked at regular intervals so you can see them right away and do something before they get out of hand. Some of the things you might want to monitor about pest populations include: Is the pest present/absent? What is the distribution all over or only in certain spots? Is the pest population increasing or decreasing? 4. Establish action threshold (economic, health or aesthetic) How many are too many? In some cases, a certain number of pests can be tolerated. Soybeans are quite tolerant of defoliation, so if you have only a few caterpillars in the field and their population is not increasing dramatically, there is no need to do anything. Conversely, there is a point at which you MUST do something. For the farmer, that point is the one at which the cost of damage by the pest is MORE than the cost of control. This is an economic threshold. Tolerance of pests varies also by whether or not they are a health hazard (low tolerance) or merely a cosmetic damage (high tolerance in a non-commercial situation). Personal tolerances also vary many people dislike any insect; some people cannot tolerate dandelions in their yards. Different sites may also have varying requirements based on specific areas. White clover may be perfectly acceptable on the sides of a tee box on a golf course, but unacceptable in th e fairway where it could cause confusion in the field of play.[4] 5. Choose an appropriate combination of management tactics For any pest situation, there will be several options to consider. Options include, mechanical or physical control, cultural controls, biological controls and chemical controls. Mechanical or physical controls include picking pests off plants, or using netting or other material to exclude pests such as birds from grapes or rodents from structures. Cultural controls include keeping an area free of conducive conditions by removing or storing waste properly, removing diseased areas of plants properly. Biological controls can be support either through conservation of natural predators or augmentation of natural predators[5]. Augmentative control includes the introduction of naturally occurring predators at either an inundative or inoculative level[6]. An inundative release would be one that seeks to inundate a site with a pests predator to impact the pest population[7][8]. An inoculative release would be a smaller number of pest predators to supplement the natural population and provide ongoing control.[9] Chemical controls would include horticultural oils or the application of pesticides such as insecticides and herbicides. A Green Pest Management IPM program would use pesticides derived from plants, such as botanicals, or other naturally occurring materials. 6. Evaluate results How did it work? Evaluation is often one of the most important steps.[10] This is the process to review an IPM program and the results it generated. Asking the following questions is useful: Did your actions have the desired effect? Was the pest prevented or managed to your satisfaction? Was the method itself satisfactory? Were there any unintended side effects? What will you do in the future for this pest situation? Understanding the effectiveness of the IPM program allows the site manager to make modifications to the IPM plan prior to pests reaching the action threshold and requiring action again. Notes 1. ^ United States Environmental Protection Agency, Pesticides and Food: What Integrated Pest Management Means. 2. ^ http://www.umass.edu/umext/ipm/publications/guidelines/index.html. 3. ^ Bennett, Et Al., Trumans Scientific Guide to Pest Management Operations, 6th edition, page 10, Purdue University/Questex Press, 2005. 4. ^ Purdue University Turf Pest Management Correspondence Course, Introduction, 2006 5. ^ http://www.knowledgebank.irri.org/IPM/biocontrol/ 6. ^ http://www.hort.uconn.edu/ipm/veg/htms/ecbtrich.htm 7. ^ http://pinellas.ifas.ufl.edu/green_pros/ipm_basics.shtml 8. ^ http://www.knowledgebank.irri.org/IPM/biocontrol/Inundative_release.htm 9. ^ http://www.knowledgebank.irri.org/IPM/biocontrol/Inoculative_release_.htm 10. ^ Bennett, Et Al., Trumans Scientific Guide to Pest Management Operations, 6th edition, page 12, Purdue University/Questex Press, 2005. References * Pests of Landscape Trees and Shrubs: An Integrated Pest Management Guide. Steve H. Dreistadt, Mary Louise Flint, et al., ANR Publications, University of California, Oakland, California, 1994. 328pp, paper, photos, reference tables, diagrams. * Bennett, Gary W., Ph.d., Owens, John M., Ph.d., Corrigan, Robert M, Ph.d. Trumans Scientific Guide to Pest Management Operations, 6th Edition, pages 10, 11, 12, Purdue University, Questex, 2005. * Jahn, GC, PG Cox., E Rubia-Sanchez, and M Cohen 2001. The quest for connections: developing a research agenda for integrated pest and nutrient management. pp. 413-430, In S. Peng and B. Hardy [eds.] â€Å"Rice Research for Food Security and Poverty Alleviation.† Proceeding the International Rice Research Conference, 31 March 3 April 2000, Los Baà ±os, Philippines. Los Baà ±os (Philippines): International Rice Research Institute. 692 p. * Jahn, GC, B. Khiev, C Pol, N. Chhorn and V Preap 2001. Sustainable pest management for rice in Cambodia. In P. Cox and R Chhay [eds.] â€Å"The Impact of Agricultural Research for Development in Southeast Asia† Proceedings of an International Conference held at the Cambodian Agricultural Research and Development Institute, Phnom Penh, Cambodia, 24-26 Oct. 2000, Phnom Penh (Cambodia): CARDI. * Jahn, GC, JA Litsinger, Y Chen and A Barrion. 2007. Integrated Pest Management of Rice: Ecological Concepts. In Ecologically Based Integrated Pest Management (eds. O. Koul and G.W. Cuperus). CAB International Pp. 315-366. * Kogan, M 1998. INTEGRATED PEST MANAGEMENT:Historical Perspectives and Contemporary Developments, Annual Review of Entomology Vol. 43: 243-270 (Volume publication date January 1998) (doi:10.1146/annurev.ento.43.1.243) * Nonveiller, Guido 1984. Catalogue commentà © et illustrà © des insectes du Cameroun dintà ©rà ªt agricole: (apparitions, rà ©partition, importance) / University of Belgrade/Institut pour la protection des plantes * US Environmental Protection Ag