GENEALOGY
Original source for
Canadian release was Yugoslavia and Italy. The agent is well
established in British Columbia. Mecinus janthinus was approved
for release in the U.S. in 1995. It migrated from southern British
Columbia into northern Stevens County and was first documented in
2000. The first known U.S. collections and releases took place in
Stevens County WA. Field Insectaries are being established
throughout the county.
LIFE CYCLE
Starting in June
females lay a single egg per chewed out cavity in the toadflax
stems and seal the hole with a cap of chewed material. When the
eggs hatch the larvae begins tunneling within the stem, increasing
the size and length of the tunnel as they grow. After about a
month the larvae stop tunneling and over several more weeks pupate
into a new adult. These new adults remain inside the stem during
the winter. Snow cover helps the dormant adults inside the stems
survive the freezing temperatures of winter. Starting in May these
new adults chew their way out of the stem, feed, and in June start
laying eggs.
EFFECT
Adult feeding does
substantial damage to the leaves. An attacked plant exhibits
leaves with "buckshot" holes. The larval stem tunneling
disrupts the food transport system between the roots and the
leaves. At the initial collection sites in northern Stevens County
the impact of this agent has been remarkable.
REDISTRIBUTION
This agent can be collected in late May and June. It is a focus of
collections and redistribution in Stevens County. The population
of this agent is on the increase in the county.
COMMENTS
At the initial
collection sites in northern Stevens County this agent has proven
highly destructive to Dalmatian Toadflax. At numerous new sites
the population is increasing and damage is evident. A county wide
grid of release sites has been selected and will receive the bulk
of the insects collected over the coming years. It is expected
that the populations of the insect will increase at these
undisturbed "Field Insectaries" and move out into all
areas of the county where Dalmatian Toadflax is found, which is
almost everywhere.
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Mecinus janthinus
Mecinus janthinus adult
Mecinus janthinus breeding
Mecinus janthinus damage |
