Potential benefits of slowing the gypsy moth's spread.

The potential benefits ofa proposed program to slow the spread ofthe gypsy moth, Lymantna dispar (L.), are assessed A GiS model, which may have application to other eptdemtological analyses, was developed to assess the physical spread over a 25 year period. Economic models were developed to estimate potential benefus from reduc ed management acttvutes. tunber production, residential Impacts, and recreation participation Potential benefits [en the greatest, medium, and least benefit scenarios were about $3,800, $2,300, and $800 mtllton. present value, respectively About X3Ck oj these benejits were obtained from delaying residential impacts South J Appl For 20(2):65-73. The gypsy moth. Lymantria dispar (1.), has received great attention and has been subjected to man) management acnv1­ ties since Its accidental mtroductron III the Boston, Massa­ chusetts area m 1869. It mitially spread north following the ( prevailing winds. However, It was not until the second halfof the 20th century that the southern and westerly infestation accelerated (McManus and Me Intyre 1981). ThIS mfestanon has now reached West V irgrma, V irgima, and parts of north­ east North Carolma, The general spread is expected to contmue south and west. lndrvidual Isolated mfestanons. sorneurnes called "spots," can occur great distances m front (If the general spread when egg masses or other life stages are transported by humans on vehicles or outdoor household articles. A Slow-The-Spread (STS) pilot project, imtrally called the gyp~y moth Contain­ ment Program, to reduce the rate of spread. was proposed III 1990. This study assessed Slow-The-Spread's likely eco­ norrnc benefits The gypsy moth mfestation may be conceived as moving forward m three zones, the Generally Infested Zone, the Transition Zone, and the Unifested Zone. The Generally Infested Zone ranges from continuous populations. where habitat exists and the populations have been through at least NOI~ Thrstudy wav performed In 11)9()-l)] while the author ""a~ 011 the faculty mthe DepartrnentofForestry. VPI&SU underaCooperauve Agreement WIth the USDA-Fole~t Sen u.e Nm theustern I'ore,t Expenment Stanon We gratefully acknowledgethe many contnbu­ nons of numerous colleagueone outbreak episode, to low level populations where zero to light defohation occurs. The Transiuon Zone is adjacent to the Generally Infested Zone. male moth captures are discon­ tmuous, and outbreaks have not yet occurred The Unmfested Zone contains only Isolated spots. Slow-The-Spread would be Implemented in the Transi­ non Zone. Detection efforts would be intensified hy uving one kilometer pheromone baited trap gnds and and supple­ mennng them With 500 and 250 m intensive gnds If initial results indicated the hkcly presence ofgypsy moth The plan rs to discover small, low density infestations which now go undiscovered An mtensive treatment program would be implemented concurrently Any detected infestation abov e a threshold level 1~ treated or mtensively monitored. Exrstmg spray­ mg techniques usmg diflubenzuron and Bacillus thurtngiensts val' kurstaki arc used. In addmon, Gypchek (VIruS). maung disruption phermones, stenle male mating, and mass trapping techniques, which are all gypsy moth specrfrc, are available for environmentally sensitive areas. Slow-The-Spread Will not affect the moth in the Generally Infested Zone nor will it elumnate its spread. The fundamental benefit 01 Slow-The-Spread is to slow the rate at which land enters the Generally Infested Zone from the Transinon Zone. This strategy can be likened to that in human medicme where death ISnot prevented. only postponed Eradicauon programs for isolated infestations m the Uninfested Zone. ahead of the Transrtion Zone. will