1 ECOLOGICAL RISK ASSESSMENT OF CURRENT-USE PESTICIDES IN THE SIXAOLA WATERSHED, COSTA RICA A Dissertatin Presented in Partial Fulfillment f the Requirements fr the Degree f Dctr f Philsphy with a Majr in Sil and Land Resurces in the Cllege f Graduate Studies University f Idah and with a Cncentratin in Bidiversity Cnservatin and Agrfrestry in the Graduate Schl Centr Agrnómic Trpical de Investigación y Enseñanza by Beth A. Plidr August 2007 Majr Prfessrs: Matthew J. Mrra, Ph.D. and Eduard Smarriba, Ph.D.
3 iii ABSTRACT Amng the mst imprtant research pririties identified in trpical ectxiclgy is the need fr risk assessment mdels specific t pesticide fate and txicity in trpical watersheds. A number f different pesticides are applied in the Sixala watershed, Csta Rica t prduce exprt-quality plantains and bananas. Fllwing an eclgical risk assessment framewrk, the principal expsure pathways, envirnmental fate, and bilgical effect f current-use pesticides are integrated t prvide an estimate f eclgical risk t aquatic resurces in the Sixala watershed. Risk assessment f pesticide use in this regin is essential fr the identificatin f cnservatin r restratin pririty areas, as well as fr the develpment f better land management practices that address reginal agriculture, cnservatin, and public health pririties. As pesticide applicatin practices have nt been previusly dcumented in the Sixala watershed, the different pesticide applicatin regimes used in banana and plantain prductin are presented and principal rutes f human and eclgical expsure are identified. Annual applicatin rates range frm less than 3 kg a.i./ha t mre than 45 kg a.i./ha, and principal rutes f expsure are primarily related t gaps in agrchemical r pest knwledge and the lack f apprpriate infrastructure. A study f sil characteristics, in farms representing the range pesticide applicatin regimes in plantain, suggests that fldplain sil prperties imprtant fr agricultural prductin and agrchemical fate r transprt are primarily driven by clay mineralgy and hydrlgic prcesses. Hwever, these fldplain sils are extremely hetergeneus ver bth large and small tempral and spatial scales, and present a challenge in estimating pesticide mvement t aquatic resurces frm agricultural areas. A number f different pesticides were measured in reginal aquatic resurces using bth water grab samples and passive samplers (SPMDs). Field experiments t calibrate SPMD pesticide uptake rates shwed that bifuling was nt an imprtant factr in SPMD pesticide sequestratin ver time, althugh several different stream characteristics may be imprtant in the interpretatin f SPMD-derived stream pesticide cncentratins. Field-measured pesticide cncentratins are integrated with mdeled pesticide cncentratins, knwledge f
4 iv sil and water prperties, primary rutes f expsure, and available txicity datasets t prvide an assessment f risk fr aquatic resurces in the Sixala watershed based n the hazard qutient methd. Hwever, given the unknwn effects f pesticide mixtures and climatic cnditins n txicity, the lack f extensive trpical species txicity data, and the cmplex species interactins and dynamic hydrlgic regimes present in trpical landscapes, this methd may nt prvide the mst prtective r cnservative apprach fr risk assessment in trpical envirnments.
5 v ACKNOWLEDGEMENTS I wuld like t thank my cmmittee fr prviding me with the pprtunity and supprt t design and implement this research prject, frm start t finish. Over the past fur years, my majr prfessr, Matt Mrra, was an unwavering surce f encuragement, guidance, and supprt. Additinally, withut the interest, technical expertise, and dedicatin f Luisa Castill, my advisr at Universidad Nacinal, and Clemens Ruepert at the Institut Reginal de Estudis en Sustancias Tóxicas (IRET), many parts f my research wuld nt have been pssible. Thanks t Eduard Smarriba, my c-advisr at CATIE, fr his cnstant interest, enthusiasm, and remarkable visin. Als t Paul McDaniel, fr his expert knwledge and humr in the field, as well as his respectful supprt f students. A special thank yu t Frank Lpez and Carls Mrales at CATIE fr prviding me with essential strage and lab space, a methd t btain slvents, analytical assistance, and their friendship. Als at CATIE, thanks t Patricia Leandr, directr f the sils lab, fr her efficiency and prfessinalism, and t Yaneth Sanchez fr grinding all my sil samples. At the University f Idah, thanks t Anita Falen and Vladimir Brek, wh welcmed me int their labs and prvided indispensable guidance and assistance, even thugh my nce a year visit was ften a surprise. Thank yu t the hundreds f individuals in the cmmunities f Gandca, Sixala, Margarita, Manzanill, Hne Creek, Cahuita, and the BriBri-Cabecar Indigenus Territries fr their interest and hspitality, fr prviding access t their farms r rivers, and fr sharing their stries. Especially t Lilleth in Sixala fr sharing her knwledge f the river and her rainfall data, t the Aguilas family in Gandca fr dnating their bat, and t the ladies f ACOMUITA fr their lgistical advice and laughter. Special thanks t my hard-wrking field assistants, Eduard Stuart Jacksn and Jeisn Chales Rjas, and t their extrardinary families. T my Talamanca teammates Leigh, Jan, Chris, and Ruth fr sticking tgether and always willing t lend each ther a helping hand, r huse, r a car, r a field assistant. Especially t Leigh fr early mrning runs, keeping my walls clean, and fr being such a gd friend. Finally, thanks t my family and friends fr their cnstant affectin and
6 vi ptimism, especially Jan Schipper wh prvided me with endless encuragement, inspiratin, and supprt. Dissertatin research funding was prvided by a fellwship frm the Natinal Science Fundatin s Integrative Graduate Educatin and Research Traineeship (IGERT) prgram, grant number , and by a Natinal Science Fundatin Experimental Prgram t Stimulate Cmpetitive Research (EPSCR) Fellwship.
7 vii TABLE OF CONTENTS Authrizatin t submit dissertatin... ii Abstract...iii Acknwledgements... v Table f cntents... vii List f tables... ix List f figures... xi List f appendices...xiii Chapter 1: Pesticide applicatin practices, pest knwledge, and cst-benefits f plantain prductin in the BriBri-Cabécar Indigenus Territries, Csta Rica... 1 Abstract... 1 Intrductin... 2 Methds... 5 Results and Discussin... 6 Cnclusin References Tables Figures...30 Chapter 2: Interpreting fldplain sil variability at different scales: Implicatins fr agrchemical mdeling in Csta Rica Abstract Intrductin Methds Results Discussin Cnclusin References Tables Figures Appendices...75
8 viii Chapter 3: Pesticide sequestratin in passive samplers (SPMDs): Bifuling and deplyment time in a trpical watershed Abstract Intrductin Methds Results Discussin Cnclusin References Tables Figures Chapter 4: Aquatic eclgical risk assessment f current-use pesticides: A cmparisn f field measurements vs. risk assessment mdels Abstract Intrductin Methds Results and Discussin Cnclusins References Tables Figures Appendices...177
9 ix LIST OF TABLES Chapter 1 Table 1. Demgraphic and land-hlding characteristics f rapid rural appraisal participants within the Bribri-Cabécar Indigenus Territries Table 2. Ranking f agricultural pests by rapid rural assessment participants Table 3. Rapid rural appraisal f participant banana weevil knwledge and methds f cntrl...24 Table 4. Summary f pesticide use regimes in banana and plantain prductin in Talamanca, Csta Rica...25 Table 5. Characteristics f agrchemical use by rapid rural appraisal participants in mnculture plantain farms...26 Table 6. Plantain market ptins in the Bribri-Cabécar Indigenus Territries in descending rder frm best fruit quality...27 Table 7. Summary f benefits, csts, and agrchemical use in indigenus plantain prductin...28 Table 8. Summary f applied agrchemicals in Talamanca, Csta Rica fr banana and plantain...29 Chapter 2 Table 1. Descriptive statistics fr carse-scale tpsils...63 Table 2. Pearsn's crrelatin cefficients fr carse scale tpsils...63 Table 3. Sil prperty averages and standard deviatins fr carse-scale samples by 250m distance classes...64 Table 4. Cmparisn f first hrizn sil prperties in fine-scale farm sites flded r nt-flded in January Chapter 3 Table 1. A cmparisn f Sixala River and Cana Creek water chemistry characteristics frm a ne-day "snapsht" sample f streams in June Table 2. Cmparisn f suspended slids and bttm sediment characteristics in the Sixala River and the Cana Creek study sites Table 3. Current pesticides used in Csta Rica and their analytical parameters...129
10 x Chapter 4 Table 1. Chlrpyrifs, difencnazle, and terbufs applicatin in fur different banana and plantain prductin regimes in the Sixala watershed Table 2. Predicted Envirnmental Cncentratins (PECs) based n three different pesticide entry fractins (EF) in five study sites Table 3: Lwest calculated acute and chrnic n effect cncentratins (NECs) fr chlrpyrifs, difencnazle, and terbufs...170
11 xi LIST OF FIGURES Chapter 1 Figure 1. Agrchemical use in plantain farms as reprted by participants in the 2004 rapid rural appraisal cmpared t participants in the 2006 plantain cst-benefit study...30 Figure 2. Median values f agrchemical applicatins and quantity applied during each applicatin by exprters vs. natinal market prducers...31 Chapter 2 Figure 1. Map f study area and lcatin f sil sampling sites 65 Figure 2. Bx plts f fine-scale sil samples by measured sil prperty and hrizn...66 Figure 3. Cefficient f variatin fr fine-scale sil prperties by hrizn...69 Figure 4. Representative XRD trace f sil mineralgical prperties...70 Figure 5. Bx Plts f PCA scres by 250m distance class fr first fur principal cmpnents Figure 6. Median fine-scale percent rganic matter, sand and clay values in fine-scale distance classes by median hrizn depth...72 Figure 7. Bx plts f PC values fr first hrizn f fine-scale samples by flded r nt-flded in January Figure 8. Bx plts f first fur principal cmpnents fr all fine-scale samples by hrizn...74 Chapter 3 Figure 1. Lcatin f SPMD experimental sites in the Sixala Watershed Figure 2. Cmparisn f stream characteristics (stream discharge, flw velcity, ttal suspended slids, and disslved xygen) amng study sites and study perids Figure 3. SPMD sequestratin f current-use pesticides, chlrpyrifs, terbufs, and difencnazle Figure 4. Bifilm weight vs. SPMD-chlrpyrifs in Cana Creek Figure 5. Cmparisn f visual bifuling, ttal suspended slids, average bifilm weight as percent f SPMD weight in Cana Creek and Sixala River Figure 6. Predictin f time-weighted chlrpyrifs water cncentratins using different Rs values fr SPMD uptake rates Figure 7. Ptential stratificatin f cmpunds during lw flw cnditins...138
12 xii Chapter 4 Figure 1. Water and SPMD sampling sites in the Sixala Watershed, Csta Rica Figure 2. Cntributin f prductin regime t ttal pesticide lading in Sixala watershed Figure 3. Cntributin f chlrpyrifs, difencnazle, and terbufs t ttal annual pesticide lading in Sixala watershed Figure 4. Maximum 28-d average pesticide cncentratins in streams calculated frm SPMD deplyment in six surface water sites in the Sixala watershed Figure 5. Maximum pesticide cncentratins detected in water grab samples in seven Sixala watershed sites and ne Estrella watershed site Figure 6. Mdeled acute risk based using PECs with 100% entry difencnazle and level 3 fugacity mdels fr chlrpyrifs and terbufs Figure 7. Acute and chrnic risk qutients calculated fr an bserved fish kill in the Cana study site...176
13 xiii LIST OF APPENDICES Chapter 2 Appendix A. Sil Temperature...76 Appendix B. Summary f Fine-Scale Sil Transect Samples...77 Appendix C. Sil Transect Stratigraphy f Fine-Scale Farm Sites...80 Appendix D. Trend Surface Analyses...83 Appendix E. Carse-Scale Bx Plts and Scatter Plts...86 Appendix F. Carse-Scale Principal Cmpnents Analysis (PCA)...90 Appendix G. Relatinship between Fine Scale Exchangeable vs. Extractable Catins...91 Appendix H. Fine-Scale Distance Class Averages and Median Values...92 Appendix I. Fine-Scale Principal Cmpnents Analysis (PCA)...96 Chapter 4 Appendix A: Fugacity Mdel Inputs and Outputs Appendix B: Study Site Stream Characteristics Appendix C: Selected Acute and Chrnic Txicity Values Appendix D: Acute and Chrnic Risk Qutients fr Stream Sites Appendix E: Quebrada Cana Fish Kill Data...188
14 1 Chapter One Pesticide Applicatin Practices, Pest Knwledge, and Cst-Benefits f Plantain Prductin in the BriBri-Cabécar Indigenus Territries, Csta Rica* Abstract The use f pesticides in the cultivatin f cash crps such as banana and plantain is increasing, in Csta Rica and wrldwide. Agrchemical use and ccupatinal and envirnmental expsures in exprt banana prductin have been dcumented in sme parts f Central America. Hwever, the extent f agrchemical use, agricultural pest knwledge, and ecnmic cmpnents in plantain prductin are largely unknwn in Csta Rica, especially in remte, high pverty areas such as the Bribri-Cabécar Indigenus Territries. Our bjective was t integrate a rapid rural assessment f indigenus farmer pesticide applicatin practices and pest knwledge with a cst-benefit analysis f plantain prductin in the BriBri-Cabécar Indigenus Territries, fr the develpment f better agricultural management practices and imprved regulatry infrastructure. Interviews cnducted with 75 husehlds in 5 indigenus cmmunities shwed that ver 60% f participants grew plantain with agrchemicals. Of these plantain farmers, ver 97% used the insecticide chlrpyrifs, and 84% applied nematicides, 64% herbicides, and 22% fungicides, with nly 31% f participants reprting the use f sme type f prtective clthing during applicatin. The banana weevil (Csmplites srdidus Germar) was ranked as the mst imprtant agricultural pest by 85% f participants, yet nly 28% culd assciate the adult and larval frm. A cst-benefit analysis cnducted with a subset f 26 plantain farmers identified several natinal markets and ne exprt market fr plantain prductin in the Indigenus Territries. Yearly incme averaged $6200/ha and yearly expenses averaged $1872/ha, with average cst-benefit rati f 3.67 fr plantain farmers. Farmers applied an average f 9.7 kg a.i./ha/yr f pesticide prducts and 375 kg/ha/yr f fertilizer, but thse wh sld their fruit t the natinal markets applied mre nematicides, herbicides, and fertilizers than thse wh sld primarily t exprt markets, suggesting a lack f apprpriate applicatin knwedge. Results indicate that the quantity f agrchemicals applied in plantain cultivatin are less than that
15 2 applied in exprt banana, but the absence f apprpriate agrchemical applicatin practices in plantain cultivatin may pse serius risks t human and envirnmental health. Culturally apprpriate farmer educatin and certificatin prgrams are needed as well as the develpment f safe-handling practices, regulatry infrastructure, and adequate agrchemical strage, transprt, and waste dispsal facilities. Intrductin Cash crps prvide natins arund the glbe with imprtant surces f freign exchange, fd security, emplyment, and infrastructure develpment (Barham et al. 1992, Fafchamps 1992, Carvalh 2006). Banana and plantain (Musa spp.) are tw cash crps in Csta Rica that cmprise ver 25% f Csta Rica's freign exchange (Hernandez et al. 2000), cntributing t substantial incme generatin and emplyment pprtunities in bth lcal and natinal ecnmic sectrs. Csta Rica is currently the secnd largest exprter f bananas in the wrld, exprting 95% f ver 2.2 millin metric tns f bananas prduced annually, and the furth largest exprter f plantains in the wrld, exprting ver 40% f 70,000 metric tns f plantain prduced annually (FAO 2007). Agricultural prductin wrldwide has been accmpanied by cntinuus grwth in the number and quantity f agrchemicals applied t crps (Carvalh 2006). This trend is increasingly evident in Central America, where pesticide use has essentially dubled during the past 20 years (Wesseling et al. 2005), frm an estimated 30,000 tns f active ingredients applied annually in the 1980s t ver 57,000 tns by 1999 (Wesseling et al. 2001a). In the year 2000, Csta Rica ranked secnd in the wrld in the amunt f pesticides applied per unit area, with an average f 52 kg a.i./ha, and furth in the wrld in fertilizer use with 385 kg a.i./ha (Wrld Resurces Institute 2007). Currently, an estimated 280 different pesticides are imprted int Csta Rica and sld under mre than 2,000 different brand names (de la Cruz and Castill 2003). In 1998, ver 18,000 metric tns f frmulated agrchemicals were imprted int Csta Rica (de la Cruz and Castill 2003), mre than ne-third f which are used n banana and plantain prductin (Castill et al. 2000). The majrity f imprted chemicals are fungicides, fllwed by herbicides, and less frequently, insecticides and nematicides (de la Cruz and Castill 2003). Pesticide use is assciated with envirnmental
16 3 cntaminatin and human health prblems wrldwide (Lacher and Gldstein 1997, Dinham and Malik 2003, Marni et al. 2006). A number f human and envirnmental pisnings have been dcumented in cmmercial banana plantatins in Csta Rica and Central America (Castill et al. 1997, Castill et al. 2000, Sass 2000, Wesseling et al. 2001b, Wesseling et al. 2005). Althugh increased dcumentatin and research n agrchemical use in banana plantatins are still badly needed, the need is even greater fr such infrmatin relevant t plantain cultivatin. N studies are knwn regarding pesticide use n plantain farms in Csta Rica, despite the fact that exprt quality plantain prductin in Csta Rica rughly fllws the same agrchemical regime as cmmercial banana. Agricultural lands in the Sixala River Valley, lcated in the Talamanca regin f sutheastern Csta Rica, prvide 52% f the plantain, 90% f the rganic banana, and 6% percent f the cmmercial banana prductin in Csta Rica (Municipality f Talamanca 2003). Bth plantain and banana have had a prfund impact n the ecnmy and envirnment f this prest regin f Csta Rica, and currently cnstitute the primary surce f incme fr area residents either as revenue directly generated frm husehld farms r as wage labr n cmmercial plantatins (Brge and Castill 1997, Dahlquist et al. 2007). Cmmercial banana prductin is limited t apprximately 3,000 ha alng the lwer prtins f the Sixala River, where bananas fr exprt are grwn n large-scale plantatins with intensive use f agrchemicals. Cmmercial banana prducers are large landwners wh are required by the transnatinal cmpanies purchasing and marketing their fruit t meet strict quality standards and use prescribed prductin practices, including the use f large quantities f agrchemical inputs (Hernandez et al. 2000). It is estimated that up t 45 kg a.i./ha/yr are applied n these cmmercial banana plantatins (IRET 2000, de la Cruz and Castill 2003). Unlike banana, where the majrity f fruit is exprted, plantain in Csta Rica is grwn fr bth natinal and internatinal markets (FAO 2007). Upstream frm the cmmercial banana plantatins, exprt-quality plantain is grwn with mderate t intensive agrchemical use in rganized cperatives f husehld-plantain farms based n technlgy and knwledge adpted frm cmmercial banana prductin. It has been estimated that between 10 and 15
17 4 kg a.i./ha/yr f pesticides are applied in intensive exprt-plantain prductin (IRET 2000). Farthest upstream in the Bribri-Cabécar Indigenus Territries, banana and plantain are grwn n small-scale husehld farms in a variety f different agricultural systems ranging frm rganic banana and plantain in mixed agrfrestry systems, t mncultures with mderate agrchemical use (Dahlquist et al. 2007). Plantain has histrically been part f subsistence prductin in the Bribri-Cabécar Indigenus Territries, and was nt grwn fr exprt until the late 1980s (Villalbs and Brge 1998). With the highest cncentratin f pverty in Talamanca ccurring within the indigenus territries (Municipality f Talamanca 2003), plantain quickly became an imprtant cash crp and much needed surce f incme fr indigenus farmers. In the Bribri-Cabécar Indigenus Territries, histrical crpping systems such as the cultivatin f basic grains, caca agrfrestry systems, and traditinal fallws are rapidly being abandned in favr f mnculture plantain cultivatin fr natinal and exprt markets (Dahlquist et al. 2007). During the past 20 years, plantain cultivatin in Talamanca has increased frm 1,270 ha f plantain in prductin in 1981 (Smarriba 1993) t ver 6,600 ha in 2001 (Municipality f Talamanca 2003), representing a significant landuse change in the regin. Little is knwn abut pest management and agrchemical use within the Bribri-Cabécar Indigenus Territries. N infrmatin exists n the intensity and frequency f pesticide applicatins, pesticide csts, market ptins, r farmer knwledge f agrchemical alternatives and pest bilgy. Farmers within the territries have few ecnmic resurces and pr access t health and educatinal facilities, including agricultural extensin services. Legislatin regulating pesticide use is absent within the Indigenus Territries. These factrs have been assciated with high incidence f envirnmental and human pisnings in ther areas (Aragn et al. 2001, Hurtig et al. 2003, Knradsen et al. 2003, Karlssn 2004). Our bjectives were t determine the extent f agrchemical use and pest management knwledge in banana and plantain cultivatin as well as the csts and benefits f plantain prductin fr the Bribri-Cabécar Indigenus farmers. This infrmatin is essential fr any further research, cnservatin, r rural develpment effrts in the Indigenus Territries as well as fr natinal and reginal public health and agricultural management initiatives.
18 5 Methds Our wrk integrates tw different studies cnducted within the Bribri-Cabécar Indigenus Territries frm 2004 t 2006: a rapid rural appraisal f plantain and rganic banana prductin and integrated pest management practices, and a cst-benefit analysis f plantain prductin. Bth studies were based n participatry methds (Mikkelsen 1995) fr integratin int larger biphysical research prjects n integrated pest management and eclgical risk assessments fr pesticide use Rapid Rural Appraisal A rapid rural appraisal (RRA) f 75 husehlds was cnducted in five banana- and plantaingrwing cmmunities (Shirles, Amubri/Tsuidi, Sepéque, Gavilan Canta, and Bca Urén) within the Bribri-Cabécar Indigenus Territries frm June-August Methds included semi-structured interviews, participant bservatin, transect walks, and infrmal discussins with key infrmants and farmers (Mikkelsen 1995). Organic banana farmers were included since rganic banana is ften grwn in agrfrestry systems that include plantain. In each f the five cmmunities, 15 families that cultivated banana, plantain, r bth were randmly selected and interviewed with the assistance f tw lcal indigenus prmters. Interview questins cvered subjects such as plantain and banana management and pest cntrl techniques, farmers' knwledge and attitudes regarding the pest status f the banana weevil and the effectiveness f cntrl methds, the amunt, type, and frequency f pesticides used fr plantain prductin, methds f pesticide handling and strage, prtectin used during applicatin, health effects experienced, and why farmers chse t use r nt use pesticides Plantain Cst-Benefit Analysis Twenty-six mnculture plantain farmers frm the primary plantain-prducing cmmunities f Shirles and Sepéque, wh had been invlved in an nging sil quality research prject, participated in an intensive study f the csts and benefits f plantain prductin within the Indigenus Territries. With the aid f lcal agricultural extensinists, farmers were asked t reprt all surces f incme frm their plantain prductin, including the different natinal and exprt markets that they sell their fruit t each week. Farmers were then asked t list all csts assciated with their plantain farms including the type and quantity f agrchemicals
19 6 used, equipment rented, wrkers paid, and transprtatin csts. Cmparisns f ttal incme generated and ttal csts expended per hectare per year were then calculated with farmers t help them determine the financial status f their plantain prductin. Data Analysis and Triangulatin Fr bth datasets, interview data were cded and descriptive statistics were calculated. Where pen-ended questins were used, respnses were aggregated by tpic and the percentage f participants mentining each tpic was calculated. A Kruskal-Wallis test f variance and simple linear regressin were cnducted t determine significant relatinships and crrelatins amng farmer demgraphics and pesticide use. One-way analyses f variance (ANOVA) at the 95% cnfidence level were used t test fr significant differences amng different farmer grups in the cst-benefit analysis. Amunt f fertilizer was calculated based n the cmbined elemental cmpsitin f the tw mst widely used prducts, urea (46% N) and a cmplete N-P-K frmula ( % respectively). Active ingredients fr pesticides were calculated based n thse prduct frmulatins available in the Bribri-Cabécar Indigenus Territries. The active ingredient value fr insecticideimpregnated plastic bags was btained frm IRET (2000), and represents the amunt f chlrpyrifs per hectare calculated by weight frm the number f impregnated plastic bags n banana plants spaced at 2 m x 2 m per hectare. All data gained thrugh literature review and interviews were triangulated thrugh bth participant bservatin and grup discussins (Mikkelsen 1995). Participant bservatin included living with cmmunity members, infrmal cnversatins with indigenus farmers and ther husehld members, participating in husehld and farming activities, and bservatins frm persnal experience thrugh wrking in the indigenus territries (Dahlquist et al. 2007). Several grup discussins fr feedback were held after each study fr reiteratin and cnfirmatin f gathered datasets. Results and Discussin Participant Demgraphics Demgraphics fr participants in the 2004 RRA are presented in Table 1. The average participant was 40 years ld and pssessed a US-equivalent educatin f 4th grade. Over half (53%) f participants had lived their entire life within the cmmunity where they were
20 7 interviewed. Sixty percent f participants interviewed grew plantain in mnculture, with an average hlding f 2.75 ha. The remaining 40% did nt grw plantain r grew it in cmbinatin with certified rganic banana in mixed agrfrestry systems (averaging 1.5 ha), in which agrchemical use is technically nt allwed. Plantain in these rganic agrfrestry systems is generally grwn fr lcal r husehld use as n market currently exists fr rganic plantain in Csta Rica. Twenty-fur percent f respndents had bth mnculture plantain farms as well as separate rganic agrfrestry banana r plantain farms. All participants cmbined represented a ttal f 123 ha in mnculture plantain and 70 ha in rganic banana r mixed rganic banana and plantain agrfrestry systems, with verall farmer hldings in banana r plantain averaging 2.5 ha. Thirty-nine percent f participants were female landwners wh cultivated an average f 2.10 ha f plantain r banana, cmpared t an average f 2.95 ha cultivated by male landwners. In a fllw-up cst-benefit study f BriBri-Cabécar farmers with mnculture plantain hldings, farm hldings were similar t thse bserved in the RRA study cnducted twyears earlier, with participants reprting mnculture plantain farms ranging frm 1 t 5 ha in size with an average farm size f 2.8 ha. This number and all f the infrmatin gained in the cst-benefit study are based n a specific "parcel" belnging t each farmer participant. Hwever, it is imprtant t nte that this number des nt always represent the ttal land hldings f participants, as many farmers have several different parcels f land under varius crpping systems, including additinal plantain, n different farms spread ut acrss the indigenus territries. In the indigenus territries, individuals and families can have many parcels f land hldings scattered acrss the territries based n inherited land, r entire cllective hldings, which if cmbined can be as much as 20 t 50 ha (Whelan 2005). Agricultural Pest Knwledge When asked t name the mst imprtant pest n their farm, ver 85% f RRA participants placed the banana weevil (Csmplites srdidus Germar) as the first r secnd mst imprtant pest, and 57% f respndents ranked black sigatka (Mycsphaerella fijiensis) as the first r secnd mst imprtant agricultural pest (Table 2). The banana weevil is als cnsidered t be the mst imprtant insect pest f bananas and plantain thrughut the
21 8 trpics (Gld et al. 2001). Damage is caused by the larva, which tunnels within the crm and interferes with nutrient uptake. Banana weevil damage can reduce yield and plantatin life, and heavy infestatin can lead t crp failure in newly planted fields (Gld et al. 2001). Plants infected with the black sigatka fungal pathgen develp necrtic lesins n leaf tissue that can cause immature ripening and crp lsses f up t 50% (Stver and Simmnds 1987; Rbinsn 1996). Other pests that affect banana and plantain were described less frequently by participants, including Panama disease (causal agent Fusarium xisprum), nematdes, palm weevils (Rhynchphrus palmarum), parrts, and thrips (C. rchidii, C. signipennis). The burrwing nematde (Radphlus similis) is cnsidered the mst damaging nematde pest f banana and plantain wrldwide, causing annual yield lsses f apprximately 20% thrugh destructin f the rt system and subsequent tppling f infected plants (Marín et al. 2002), althugh ther nematde pests can include rt-knt nematdes (Melidgyne spp.), lesin nematdes (Pratylenchus spp.), and the spiral nematde (Helitylenchus multicinctus) (Rbinsn 1996). In general, farmers mentined larger, mre visible pests mre frequently and gave them a higher ranking cmpared t agricultural pests that are less visible, a phenmenn that has been bserved in ther pest knwledge studies (Jshi et al. 2000, Mrales and Perfect 2000). Fr example, nly 10.7% f RRA participants mentined nematdes and nly 4% mentined thrips, whereas almst all participants (94.7%) mentined the banana weevil (Table 2). Hwever, althugh the banana weevil was mentined mst frequently as the mst imprtant pest, nly 28% f respndents assciated the adult weevil with the larva (Table 3). T cntrl fr banana weevil, the mst cmmnly used methd, mentined by 46.6% f participants, was applicatin f nematicide/insecticides (Table 3). Cultural cntrl methds were used by 16% f participants. Cultural cntrl methds include the remval f debris and weeds frm the base f the mat, deleafing and desuckering, remval f rtted stems, and weeding by machete. Pseudstem traps were used by 9.3% f participants and mentined by anther 22.6% (Table 3). These traps are cnstructed f tw pieces f fresh banana r plantain stem cut lengthwise and then placed n tp f each ther in the field t attract weevils away frm nearby plants (Gld et al. 2002). Phermne traps were mentined by 12% f participants. These traps cntain a lure with the aggregatin phermne f the banana