BBCA - Target Weeds - Nov 2008
Target Weeds 2012
BBCA - Target Weeds - 2012
Yellow starthistle, Centaurea solstitialis (YST) Yellow starthistle is an annual weed of primary concern in the Western USA, where it spreads over 9 million hectares of pastureland, non-cultivated and natural areas. During 2000 BBCA started a biocontrol program for YST in cooperation with USDA-ARS EBCL and PWA with the specific objective to select biocontrol agents attacking the weed at the early developmental stages. Between 2001 and 2012 several agents (fig. 1-4) were selected; among them the weevil Ceratapion basicorne completed the host specificity screening and a release petition has been accepted in 2006. Currently under study is the seed feeder weevil Larinus filiformis.
Fig. 1. Ceratapion basicorne; root and crownboring weevil (photo by L. Smith)
Fig. 2. Damage of C. Fig. 3-4. Pupa and adult of the seed feeder weevil basicorne larvae on YST Larinus filiformis (photo on left by L. Gultekin) crown and root (photo by L. Smith)
Russian thistle, Salsola spp. Salsola spp. represent one of the most troublesome weeds in the drier regions of western North America. It infests range and semiarid pasture lands as well as cropland, agricultural, residential and industrial areas. As a crop weed it can cause yield losses of greater than 50% in spring wheat. A project for the selection of new biocontrol agents for Russian thistle was started in 2003 in co-operation with USDA-ARS EBCL and PWA. At the present time several potential biocontrol candidates have been selected (fig. 5-8) and preliminary studies on their biology and host specificity are ongoing.
Fig 5. Larva of the weevil Cosmobaris scolopacea
Fig. 6. Effect of the attack of the eriophyoid mite Aceria salsolae on Russian thistle
Fig. 7. Damage of larva of the stem and fruit boring moth Gymnancyla canella
Fig. 8. The weevil Lixus rosenschoeldi found in Sicily
BBCA - Target Weeds - 2012
Perennial pepperweed, Lepidium latifolium Perennial pepperweed is a herbaceous, semi-woody mustard of Eurasian and Central Asian origin that is aggressively invading natural habitats and pastures in North America. A co-operative project for the selection and evaluation of biocontrol agents, involving BBCA and CABI Bioscience (Switzerland), started in 2005. Several associated organisms were found and are now under study (fig. 9-11). Among them, the root mining weevil Melanobaris sp. nr semistriata, the stem mining chloropid fly Lasiosina deviata and the gall forming eriophyoid mite Metaculus lepidifolii.
Fig. 9. The root-boring weevil Melanobaris sp. nr semistriata
Fig. 10. Damage of the fly Lasiosina deviata on perennial pepperweed stem
Fig. 11. Plant attacked by the mite Metaculus lepidifolii
Scotch thistle, Onopordum acanthium Scotch thistle is a biennial weed, of Eurasian and Central Asian origin that is aggressively invading natural habitats and pastures in North America. BBCA started opportunistic field surveys for the selection of new biocontrol agents in 2007. Numerous associated organisms were found and some of them are currently under study (fig. 12-15); among them the weevils Trichosirocalus briesei, Larinus latus and Lixus cardui, the stem-mining flea beetle Psylliodes chalcomerus and the root boring moth Eublemma amoena. Recently recorded in Western Turkey a new species of Aceria eriophyoid mite associated with the target weed.
Fig. 12. The root-boring weevil Trichosirocalus briesei found in Spain
Fig. 13-14. Adults and larvae of the weevil Lixus cardui
Fig. 15. The seed-feeder weevil Larinus latus in Turkey
BBCA - Target Weeds - 2012
Russian olive, Elaeagnus angustifolia Russian olive is a fast growing tree of moderate size of Eurasian and Central Asian origin. Introduced in North America as a desiderable ornamental shade tree, it became a serious weed problem in pastures, meadows and waterways. A co-operative project for the selection and evaluation of new RO biocontrol agents, involving BBCA and CABI Bioscience Switzerland started in 2007, and so far has been targeted on explorations in Turkey and Iran for potential biocontrol candidate agents (fig. 16). Impact studies and preliminary host range tests are currently ongoing with the eriophyoid mite Aceria angustifoliae (fig. 17-18).
Fig. 17. Plant attacked by the mite Aceria angustifoliae
Fig. 16. Collection on Russian olive in Iran
Fig. 18. Impact test with A. angustifoliae in Turkey
Saltcedar, Tamarix spp. Genus Tamarix consists of 90 different species and 8 of them have been introduced into the United States in the 1800's. Among them, only 2 species are considered a real threat to the natural ecosystems of the Southwest: Tamarix parviflora and T. ramosissima. Once established, saltcedar can out-compete stressed native plants and cover large areas of formerly native habitat, resulting in a less productive and less diverse environment. BBCA is involved in collections and preliminary observations on the root galling weevil Liocleonus clathratus, in cooperation with Kevin Delaney (USDA ARS, Sidney, MT, USA).
Fig. 19. The root galling weevil Liocleonus clathratus
Fig. 20-21. Biology studies with L. clathratus on potted plants and in Petri dishes
BBCA - Target Weeds - Nov 2008
Russian knapweed, Acroptilon repens Russian knapweed is a perennial weed of Central Asian origin that can rapidly colonize fields, roadsides and cultivated sites due to its vegetative reproduction from rhizomes. Plants show allelopathic effects and can be toxic to horses. During the two travels in North Eastern Iran in 2008, CABI asked BBCA to be involved in the supervision of the field activities for the search, selection and preliminary studies of potential biocontrol candidate agents associated with Russian knapweed in its native range. In addition, first field studies were carried out to assess the host–range and the biology of the eriophyoid mite Aceria acroptiloni.
Fig. 22 - 23 Russian knapweed flowerheads: healthy (left) and attacked by the eriophyoid mite Aceria acroptiloni (right)
Fig. 24. Open field experiment with the eriophyoid mite Aceria acroptiloni in Iran.
BBCA - Target Weeds - 2012
Plans for 2012 During 2012 we will follow the footsteps of last years, improving BBCA efforts in terms of new disciplines and new projects. Regarding new disciplines, in particular, we will enhance our screening improving genetic aspects of work. The target for 2012 will be to emphasize our support to EBCL in the clarification of several taxonomic question marks on some of the new potential biocontrol agents present in our pipeline. For the classic approach, our goal will be to be involved on 4 different projects for EBCL (YST, Scotch thistle, Russian thistle and saltcedar), one together with EBCL and CABI (perennial pepperweed), and two under the supervision of CABI (Russian olive and Russian knapweed). Regarding the “historical“ projects, our work on YST will be focused on the screening in open field conditions of the seed feeder Larinus filiformis in Turkey, in cooperation with Lincoln Smith (USDA-ARS, Albany, CA,USA) and Levent Gultekin (Ataturk University, Erzurum, Turkey). Laboratory and field bioassays with the weevil Lixus rosenschoeldi found on Russian thistle in Sicily, South Italy, will be repeated this year in our facilities to evaluate the oviposition and its host range in choice conditions. The screening of a new agent, a Turkish population of the stem and fruit boring moth Gymnancyla canella will start in our facilities in confined field cage conditions. Regarding Scotch thistle, we will complete genetic analysis on the root boring weevil Trichosirocalus briesei, in cooperation with Lincoln Smith (USDA-ARS, Albany, CA, USA) and Alessio De Biase (University of Rome, Italy). In addition we will complete the studies on two populations of the flea beetle Psylliodes sp. near chalcomerus, associated with Onopordum acanthium in Italy, in cooperation with Maurizio Biondi (University of L’Aquila, Italy) and Alessio De Biase (University of Rome, Italy). Moreover, we are planning the third year of the open field host range test with Lixus cardui in Plovdiv, Bulgaria, in cooperation with Dr. Vili Harizanova and Dr. Atanaska Stoeva (Agricultural University of Plovdiv, Bulgaria). Perennial pepperweed project will be focused on the host range screening of the root mining weevil Melanobaris sp. nr semistriata and the gall forming eriophyoid mite Metaculus lepidifolii in cooperation with Hariet Hinz and Esther Gerber (CABI, Switzerland) and Brian Rector (USDA ARS, Reno, NV, USA). BBCA will continue to work on collections and preliminary rearing observations on the root galling weevil Liocleonus clathratus on saltcedar, in cooperation with Kevin Delaney (USDA ARS, Sidney, MT, USA). Two open field tests will be carried out on the eriophyoid mites Aceria acroptiloni and A. angustifoliae, on Russian knapweed and Russian olive respectively in Iran and Turkey, in cooperation with Urs Schaffner (CABI, Switzerland) and Radmila Petanovic (University of Belgrade, Serbia).
BBCA - Target Weeds - 2012
Milestones 2012-2014 for Prioritized Candidate Biocontrol Agents BCA or Weed
2012
2013
2014
Trichosirocalus briesei TW: Onopordum acanthium
complete DNA analyses and morphological studies
submit paper
Psylliodes chalcomerus TW: Onopordum acanthium
complete DNA analyses and taxonomic studies
submit paper
Lixus cardui TW: Onopordum acanthium
complete open field test complete biology studies complete DNA analyses and taxonomic studies
submit petition
Larinus latus TW: Onopordum acanthium
continue HR tests
complete HR tests
submit petition
Aceria sp. new species TW: Onopordum acanthium
continue foreign explorations start preliminary biology studies
complete biology studies start HR tests
complete HR tests
Larinus filiformis TW: Centaurea solstitialis
complete open field test
submit petition
Lixus rosenschoeldi TW: Salsola tragus
complete open field test complete impact tests
submit petition
Aceria salsolae TW: Salsola tragus
test on “wind effect� on the mite colonization biology studies on the effects of predation
permit request
Gymnancyla canella TW: Salsola tragus
start HR tests
complete HR tests start genetic analysis
Cosmobaris scolopacea TW: Salsola tragus
complete open field test complete DNA analyses and morphological studies
submit paper
Lasiosina deviata TW: Lepidium latifolium
stand-by
complete biology studies complete open field test
Melanobaris sp. nr. lepidiifolii TW: Lepidium latifolium
complete biology studies complete open field test
submit petition
Metaculus lepidiifolii TW: Lepidium latifolium
complete biology studies complete open field test
submit petition
Aceria angustifolia TW: Elaeagnus angustifolia
continue open field test
complete open field test
submit petition
Aceria acroptiloni TW: Acroptilon repens
continue open field test
complete open field test
submit petition
submit petition
submit petition
Table 1. Brief summary of BBCA research activities planned for 2012-2014 on prioritized biocontrol agents. Abbreviations: TW=Target Weed; HR=Host Range.