Protection Quarterly Vol.22(1) 2007 33 searches of surrounding fields and neighbouring farms, and enquiries Cost of rapid-response eradication of a recently made of the farmers. No kudzu were found except in the one fi eld, introduced plant, tropical kudzu (Pueraria where they had been sown in a 20 × phaseoloides), from Santa Cruz Island, Galapagos 20 m plot towards its southern edge. These were treated by applying a 1% solution of Roundup™ (Monsanto, Alan Tye, Botany Department, Charles Darwin Research Station, Casilla 41% glyphosate salt) from a backpack 17-01-3891, Quito, Ecuador. Email: [email protected] sprayer. • April–May 1996 Consultations and meetings to arrange the eradication and have it approved by the regional authority. Summary (distances) and quantities of herbicide or • May, June and July 1996; February, Eradication feasibility depends on cost, other materials. April and September 1997 Complete but little information is available on the In Galapagos, Buddenhagen (2006) searches of the fi eld, with spot-treat- costs of individual eradication attempts. I documented the eradication, including ment of plants found, by spraying with report the successful eradication of tropi- the detailed costs, of two species of Rubus a 5% solution of Roundup. In May 1996 cal kudzu from Santa with limited distributions, while Budden- the remainder of the seed, which had Cruz Island, Galapagos, in a program that hagen and Yánez (2005) predicted, based not been sown, was destroyed. Dur- began within one year of its introduction at on pilot studies, the cost of attempting to ing 1996 and early 1997 some plants a single site. I document the elements con- eradicate red quinine Cinchona pubescens, produced fl owers and small immature tributing to the approximately US$1600 which is distributed over some 12,000 ha fruits, but no fruits were known to have total cost of the eradication project, which on Santa Cruz Island. Here I report the developed to maturity. All immature continued for six years. About 80% of the methods, success and cost of a project near fruits found were collected and burnt. total cost was for 108 person-hours of la- the opposite extreme of feasibility: a plant The last two plants were seen in Sep- bour and, of this, 75% was search time. whose introduction date was precisely tember 1997. Results and case characteristics are com- known, which was sown by one farmer in • March 1998, June 1999, January 2001 pared with other recently reported suc- a single fi eld in an accessible site, and for Complete searches of the fi eld, with no cessful plant eradications. which an eradication attempt was begun plants found. The plant was considered Keywords: eradication cost, Galapagos, within months of the introduction, before eradicated in January 2001. kudzu, plant eradication, Pueraria. the plant had had time to produce more seed. I also use these results, along with The site was about 18 km from the op- Introduction those of Buddenhagen (2006), as tests of erational base at CDRS by road, with the The feasibility of eradication of an intro- the Panetta and Timmins (2004) decision fi eld approximately 300 m distant from duced plant from an island depends prin- tree and scoring system for eradication the nearest parking place. The fi eld was cipally on the cost, which is itself deter- feasibility. searched systematically by passing back mined by factors such as biology, detecta- and forth in straight lines parallel to the bility, distribution and other logistical con- Study species, site and methods western edge of the fi eld, by two (or oc- siderations (Panetta and Timmins 2004). Tropical kudzu Pueraria phaseoloides casionally three) observers walking 4–6 m An empirical estimation of costs requires (Roxb.) Benth. (Fabaceae) is widely grown apart, the precise separation being deter- taking into account all these factors. In- in mainland Ecuador for ground cover in mined on the day according to the height formation from prior eradication attempts orchards, and as a plant and soil of the brizantha grass in the pas- in similar circumstances could assist in improver. It is a close relative of kudzu P. ture, which was intermittently grazed by estimating costs, but there is little infor- lobata Ohwi, one of the worst plant invad- cattle. Maximum grass height was about 1 mation available on the costs of specifi c ers of the south-eastern USA, and is itself m, although normally most grass was less plant eradication attempts. Indeed, of the an aggressive species (Mauchamp and than 0.3 m high. The broad-leaved kudzu few successful plant eradications found Muñoz 1996). A 5 lb (2.26 kg) bag of tropical plants were quite conspicuous among the by Mack and Lonsdale (2002), almost all kudzu seeds was imported to Santa Cruz grass, even when small seedlings, as long were based on personal communications Island by one farmer in 1995 and about as line of sight from above was not ob- and none was documented in any detail. one fi fth of the seeds were planted about scured by vegetation. Search lines were In a rare exception, Flint and Rehkemper the middle of that year in a single maintained with reference to posts in the (2002) estimated the total cost (but with- fi eld in the agricultural zone. According opposite fence line. out providing a breakdown) of the nearly to the farmer, they did not grow fast until completed eradication of Cenchrus echina- early 1996, when they began to develop Results tus from Laysan Island. Surprisingly, there rapidly and a few produced fl owers. The The costs in Table 1 are based on estimates are also few cost estimates available for plant was noticed by Charles Darwin Re- of hours of work carried out by CDRS staff, animal eradications (Panetta and Tim- search Station (CDRS) staff on 28 March with all costs based on the rates applicable mins 2004). It therefore seems important 1996, and when the potential danger of at the time, and labour costs apportioned to report tactics and costs, in order to con- the species was explained to the farmer, he between technical and fi eld staff time. Es- tribute to general analyses of the factors agreed to allow it to be eliminated. timates for individual trips are based on: that infl uence cost and feasibility, and to 2 person-hours for initial discovery and permit better prediction of cost and fea- The eradication project schedule was as consultation; 16 person-hours for the fi rst sibility of future projects. Since monetary follows: search and treatment; 8 person-hours for costs change, such reports should not • 28 March 1996 Discovery and initial subsequent search-treatment trips; 10 per- only present fi nancial cost, but also the consultations. son-hours in the fi rst year for desk-work elements that contribute to it in more sta- • 2–5 April 1996 The 100 × 50 m fi eld was and meetings, 2 person-hours per year ble units, such as person-hours, transport completely searched, with less thorough thereafter; US$10 per trip for transport; 34 Plant Protection Quarterly Vol.22(1) 2007 12% overhead to cover offi ce materials, Table 1. Estimated costs per annum for activities involved in the eradication equipment wear and logistical support. of tropical kudzu from Santa Cruz Island. Herbicide costs were negligible (