Project summary:
The alfalfa snout beetle (ASB) has been deemed one of the more severe pests
of alfalfa in North America, capable of destroying entire fields of alfalfa
within a single growing season. The insect was first discovered in the late
1800’s in Oswego County, NY. It is believed that the ASB was introduced
from Europe by discharge of soil/gravel ballasts onto the shores of the St.
Lawrence River and Lake Ontario from wooden sailing vessels. Since then, the
flightless beetle has been expanding its range by walking, water movement, and
transport on farm equipment. Currently, ASB infestations occur in 8 counties
in New York, and the beetle has permanently infested up to 500,000 acres, or
13% of New York State’s total cropland. Because the beetles feed primarily
on alfalfa, a major forage crop for dairy farms, the economic loss sustained
by New York dairy farms has been substantial (20 –30% decrease in net
profits). With the discontinued use of heptachlor in 1972 and DDT in the early
1980’s, ASB populations have been expanding rapidly without an effective
and ecologically sound method of control. This has lead to the exploration of
controlling ASB outbreaks by use of biological control agents, such as the entomopathogenic
fungi Metarhizium anisopliae and Beauvaria bassiana. These fungi have proven
to be effective against locust outbreaks in Australia and South America and
have been used commercially to make “green” pesticides in both areas.
Preliminary research has been conducted at Cornell in which ten fungal isolates
(six B. bassiana and four M. anisopliae) were used in lab trials to test their
lethality towards the ASB Three of the isolates tested produced 100% mortality
in 10-12 days. The primary advantage of using biological control is that no
obvious health risks to humans by entomopathogenic fungi or compounds secreted
by the fungi are evident. Furthermore, with the increasing amount of legislation
put forth to curtail the use of chemical pesticides (such as Diazinon, slated
to be phased out in the next few years by the FQPA), research into the development
of effective and relatively inexpensive bio-control methods will be crucial
for sustainable agriculture in upstate New York.
Objectives:
1. Ascertain the overall effectiveness of several different strains of both
M. anisopliae and B. bassiana for use against ASB by determining the lethal
concentration of spores and the associated mortality rate in both laboratory
and growth chamber trials.
2. Increase the effectiveness of the fungi by enhancing their virulence towards
the ASB.
3. Determine the most effective method for application of fungi to potential
field sites.
4. Implement the most effective fungal isolate and method of application in
field trials and assess the ecological impact.
5. Project evaluation.
Project staff:
Project Leader: Janice E. Thies
Project Staff: Chris Jones