Biological Control Release Site Monitoring Methods for knapweed Using Agapeta zoegana, Cyphocleonus achates , Urophora affinis, Urophora quadrifasciata, and Metzneria paucipunctella
Adapted from the video Monitoring Methods for Knapweed, by:
Nancy J. Sturdevant
USDA Forest Service
Cooperative Forestry and
Forest health production
Missoula, MT 59807
(406) 329-3281&
Sandy Kegley
USDA Forest Service
Cooperative Forestry and
Forest health production
Coeur d' Alene, ID 83815
(406) 786-7355
3 reasons why we monitor:
1. to see if the insects establish
2. determine the effect on the weed population
3. to see if the insects have spread from the release site
Insects:
1. Agapeta zoegana (sulfur knapweed moth):
A) life cycle
1) 1 generation a year
2) they lay there eggs on leafs and stems
3) eggs hatch between 7-10 days
4) larva migrate to the root crown = population grows in the root
5) adults live up to 10 days or die soon after laying eggs
B) monitoring Agapeta zoegana:
1) Phoneme traps*
a) most effective way to monitor
b) 89% effective on the sites
c) takes about 40 minutes to set up
d) has a large sampling window
e) traps should be set up around July and then should be checked after 6 weeks of sitting.
f) the traps should be placed 20 m away from insect release site
h) how to make the trap;
1.) about 12 dollars to buy
2.) make sure that you fold the sides so that all three sides of the trap ar sticky and then make sure that you have the trap placed about 2 feet above ground and let sit for a while.
2) Visual transact
a) second most efficient
b) 55% of sites (adults were recovered)
c) the advantage is that it requires little time and cost the disadvantage is that it has to be one during the warm part of the day
d) this has to be done around the peek moth flight (around July 15th)
e) slowly walk around the transepts, record how many insects you see.
3) larva sampling:
a) third most effective
b) 43% of adult recovered
c) advantage = long sampling window
disadvantage = takes up allot of time and some knowledge is required for identification **
d) has to be done around July 1st
e) how to do this:
1.) walk around the transept looking at the plant from four different directions where the insects were released
2.) remove plants from ever transact that are about 10 m apart and have 10 mm roots
3.) can dissect them in the field or at the office. you can also refrigerate the plant and dissect them at a later time.4) sweep netting
Agapeta Cyphocleonus the larval body is not c shaped larval body is c shaped has pro legs does not have pro legs
a) least effective
b) adults recovered at 38% of the sites
c) advantage = takes about 10 minutes and requires little equipment
disadvantage = done during a warm day and needs little to know cloud cover
d) done around July 15th
e) take 20 weeps at each transact site and examine the results after each site.
2. Cyphocleonus achates - or knapweed root weevil
A) life cycle
1) weevil has 1 generation per year.
2) eggs are laid on root and take about 10-12 days to hatch
3) moved to cortex
4) pupation to the root
5) adults from August to September
6) live 8-10 weeks
B) Monitoring Cyphocleonus
1) larval sampling ***
a) most effective
b) 36% effective at sites
c) method is the same as Agapeta
2) Sweep netting
a) second most effective
b) 18 % effective at sites
c) same as Agapeta
3) Visual transport
a) least effective
b) 6% effective at released sites
There are 3 insects that feed off of the seed heads:
1. Urophora affinis
A) less wing band
B) hard gulls
2. Urophora quadrifasciata
A) bold more complete wing band
B) less apparent
3. Life cycle for Urophora affinis and for Urophora quadrifasciata
A) larva cause gulls inside the seed head
B) 1-2 generations per year
C) adult is 3/16 inches in length
D) the adults peek in July
E) eggs are in the flower beds
4. Monitoring methods for Urophora affinis and for Urophora quadrifasciata
A) Seed head dissection****
1) most effective
2) advantage:
a) no equipment needed
b) little time needed
c) can be done over a long period of time
3) collect 100 seeds per site
4) dissect in field open for larva or hard gulls
5) larva - maggot
gulls - hard
B) Sweep netting
1) takes 10 minutes
2) little time required
3) best if done in middle of July to late August
4) same as Agapeta
C) Rear adults out of seed head
1) can collect seed head
2) Put the seed head in a petri dish and place it in the warm air, then let sit and the adults will come out eventually.
3) wait 8 week for all the adults to merge from the seed head
5. Metzneria Paucipunctella - seed head feeding moth
A) Life cycle
1) larva feed in the seed head
2) late June to early july the adults will merge
3) adults lay eggs at the base of the flower heads
B) Monitoring methods for Metzneria Paucipunctella
1) Seed dissection
a) most efficient
b) similar to the flies but you need 200 seed heads instead of 100
2) Sweep netting
a) same as fly
* For Agapeta pheromone trapping is the best monitoring methods
** you need to be able to know the difference between the Agapeta
and the Cyphocleonus
*** larval sampling is recommended for the Cyphocleonus
**** both larva can be in the same seed head but the moth is bigger than
the flies
By: Cindy Lofftus 4/02.
Literature Cited:
1) Monitoring Methods for Knapweed, Kegley J., Sandra, Sturdevant, and
J. Nancy, [Video], 17 minutes.
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