Subject: Purple Loosestrife, Biological Control

From: [email-masked] (Nigel Allen)
Date: Mon, 22 Aug 1994 01:23:35 GMT

I found the following item on the gopher at WSUAIX.CSC.WSU.EDU
(Washington State University).

Subject: 94-06-22 INTEREST IN BIOLOGICAL CONTROL SURGES IN WASHINGTON

     Dena Marchant -- 509/335-2867 (Work)           SPECIAL TO UNIVERSE
     June 21, 1994 -- 509/882-3483 (Home)
     INTEREST IN BIOLOGICAL CONTROL SURGES IN WASHINGTON
          PULLMAN, Wash. -- Requests for biological weed control have
     surged more than 50 percent in Washington since 1990.
          Weeds are a problem in lawns, gardens and agricultural
     lands.  But when they spread out of control in wildlands they
     gobble native habitat with the fervor of a strip developer.
          One weed now the focus of WSU biocontrol efforts is purple
     loosestrife. 
          The colorful perennial chokes out native vegetation in
     wetlands.  By destroying wetlands, it also threatens waterfowl,
     marsh birds, shore birds, raptors, song birds and other wildlife
     dependent on wetlands.  Despite a quarantine enforced by the state
     in 1990, the weed has taken over 30,000 acres in 25 Washington
     counties.  It is tall, hardy and tough to control.
          Gary Piper, an entomologist in the College of Agriculture
     and Home Economics, has established three loosestrife-eating
     insects and plans to release two more this year.
          Since coming to Pullman in 1978, Piper has released 56
     insects, mites and plant pathogens to control 22 weeds.  The tiny
     predators are established on more than a million acres in
     Washington.
          Most weeds are a problem because they arrived from Europe or
     Asia unaccompanied by the insects and diseases that keep them in
     check in their homelands.
          Weeds are prolific producers of long-lived seeds.  They are
     next to impossible to eradicate once established.  Instead
     biocontrol aims to restore a balance by importing specific insects
     and diseases to control the weed.
          By all accounts, biocontrol is a safe and inexpensive
     approach.
          "For every dollar invested in herbicide use, the return is
     $3 to $5," Piper said.  "Every dollar invested in biological
     control yields about $30."
          A conservative estimate of the returns from biological
     control in Washington is about $100,000, Piper said.
          Others cite much higher figures.
          University of California-Berkeley entomologist Marjorie Hoy
     reports biological control benefits ranging from $30 to $100.    
          To date, Piper has targeted poison hemlock, Canada thistle,
     yellow starthistle, Dalmatian toadflax, tansy ragwort, knapweed,
     rush skeletonweed, purple loosestrife, puncturevine and St.
     Johnswort.
          Weeds targeted for future biocontrol include Scotch thistle,
     houndstongue and wild morning glory.
          Biocontrol is not a fast process, Piper notes.  It takes
     time for biocontrol agents to establish and flourish.  And it
     takes time for weed seeds in the soil to be used up.  A single
     purple loosestrife plant, for example, can produce nearly 3
     million seeds in a year.
                              -30-.

--
Nigel Allen                     [email-masked]