Several insect biological control agents targeting leafy spurge
have been introduced from Europe to North America (Bourchier et al.
Using this survey method, called Very Large Scale Aerial (VLSA) imagery, Agricultural Research Service rangeland specialist Terry Booth and colleagues discovered that leafy spurge
was displacing sagebrush seedlings.
This happened when the Hyles euphorbiae, a pink-hued hawk moth, was introduced in the 1960s to combat leafy spurge
, a Eurasian perennial now present in 19 states and seven national parks.
Examples include quackgrass and Johnson grass (both have rhizomes); leafy spurge
and Canada thistle (both have creeping roots); and bermuda grass (has stolons).
Here, the native prairies have been protected for more than 50 years, but leafy spurge
has been making its way across the park since the 1970s.
We no longer have to use herbicides to control leafy spurge
, and crop production has increased.
For example, leafy spurge
(Euphorbia esula) exposed experimentally to millimolar concentrations of HQ had reduced water uptake by leaves, resulting in closed stomata and decreased photosynthesis (1).
Terry Cacek, exotic weed specialist for the National Park Service, notes that bison, elk, wild horses, and deer won't eat leafy spurge
because its sap is irritating and can cause ulcers in their mouths.
The weeds include yellow star thistle, leafy spurge
, Japanese knotweed and false brome.
Were this not so, noxious weeds such as leafy spurge
could be eliminated to the benefit of farmers, and other mycotoxins could be developed to stop gypsy moths, Asian longhorn beetles, and many other specific organisms harmful to the economy.
can be found in at least 36 states and costs more than $144 million annually for control measures and in loss of grazing land in Montana, North Dakota, South Dakota and Wyoming.
and spotted knapweed are common examples of accidentally introduced weeds.
, a rapidly spreading invasive shrub is choking out the western prairie fringed orchid in the Sheyenne National Grasslands of North Dakota and possibly in other areas; herbicides used to control spurge can kill the orchid as well.
Put another way, the benefits of cattle do not lessen the damage wrought by leafy spurge
ASSESSMENT OF BIOLOGICAL CONTROL AGENTS FOR AREA-WIDE INTEGRATED PEST MANAGEMENT OF LEAFY SPURGE
IN MONTANA AND SOUTH DAKOTA.