Progress 04/28/06 to 04/28/11
Outputs
Progress Report Objectives (from AD-416) Lippia (Verbenaceae) is a fast-growing, mat-forming weed in Australia, where it was introduced as an ornamental during the second half of the nineteenth century. Biological control is proposed as the sustainable method for this weed, with no records of arthropods associated and few for fungal pathogens. Approach (from AD-416) Collect natural enemies of Lippia; collect and curate flora and fauna specimens; maintain and specimen database; prepare and send specimens for identification; develop methods to propagate and grow Lippia in the laboratory; develop rearing techniques and study the biology of selected natural enemies; and observe host range of specimens in the field and laboratory. The distribution model was studied with a local cooperator, indicating that the distribution is a result of wind speed, precipitation, day length, temperature, population and bare soil. Higher occurrence probability existed in north-central Argentina and eastern Patagonia. The probability of occurrence falls in western Argentina. Surveying efforts were focused on establishing lab cultures of two natural enemies (the flea beetles Kuschelina). To estimate the host range, its survivorship was studied on two Lippia populations from northern Argentina and from Buenos Aires, and on other related host plants from the same habitats. The flea beetles showed specificity for Lippia. Surveys for 2 fungi were concentrated in Formosa, Santiago del Estero and Entre R�os Provinces in collaboration with a local cooperator. No fungi were found. Methods used for the monitoring of this project included periodical phone calls and E-mail exchanges with CSIRO Entomology, Indooroopilly, Australia. Also, progress reports were prepared and delivered to the funding agency.
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Progress 10/01/09 to 09/30/10
Outputs
Progress Report Objectives (from AD-416) Lippia (Verbenaceae) is a fast-growing, mat-forming weed in Australia, where it was introduced as an ornamental during the second half of the nineteenth century. Biological control is proposed as the sustainable method for this weed, with no records of arthropods associated and few for fungal pathogens. Approach (from AD-416) Collect natural enemies of Lippia; collect and curate flora and fauna specimens; maintain and specimen database; prepare and send specimens for identification; develop methods to propagate and grow Lippia in the laboratory; develop rearing techniques and study the biology of selected natural enemies; and observe host range of specimens in the field and laboratory. After taxonomical revision, genetic studies in Australia and South America revealed two taxa: P. nodiflora and P. canescens for Australia and only P. canescens for South America. Kuschelina bergi. Feeding and maternal influence of this agent was studied with newly emerged larvae from a lab culture using P. n. canescens as the host plant. Larvae were randomly assigned to cages with one plant of P. n. canescens, or P. n. nodiflora that had been cultivated from cuttings in a greenhouse. Emerging adults were counted, sexed and put (a couple from the same plant species) into containers with leaves from the same plant species, held in a rearing chamber to evaluate fertility and fecundity. The larvae from P.n. nodiflora line were used to: 1- Study the feeding preference among the three varieties of Phyla nodiflora, in relation to their prior feeding experience, and 2- Study larval development on the three Phyla species as it is affected by prior feeding experience. Survivorship curves of the last generation were compared among plants, using Cox proportional hazards model in surviving analysis. Adults emerged from the three plants in almost the same proportion as previous starvation experiments. Survivorship of K. bergi was similar. Kuschelina sp. 2. Sampled for the first time in 2006, originally identified as the sympatric species Disonycha glabrata. More taxonomical studies are needed for accurate identification. 11 adults were used to study its biology. The tarsi globose aspect and stripes on pronotum and elytra make it similar to K. bergi. Male/female can be separated looking at the division of sternite. In the field, adults were cryptic and usually under prostrate plants in contact with soil. They fed on leaves, preferably young. They are very prolific; six females collected laid about 700 eggs in five months, and continue to do so. After about 10 days larvae (N=61) emerged and fed on leaves. Three larval instar stages lasted ~22 days (N=50). Pupation occurred in the substrate (peat instead of soil) and pupation took ~ 20 days. The proportion of larvae that reached the adult stage was 63% (N=61), higher than K. bergi. Preliminary host specificity studies suggest that it feeds only on P. n. canescens. Acari, Eriophyidae Mites were surveyed and in each site, leaves, stems, and flowers were collected, placed in sealed plastic bags and checked with stereo microscope (90 X). Leaves with mites were placed in 70% ethanol for morphological studies and in absolute ethanol for molecular studies underway in Turkey. Neolasioptera sp. Stems with galls were taken to the lab for rearing/identification. Adults emerged were tentatively identified as a new species of Neolasioptera. Rearing attempts failed when stems with galls were planted among healthy plants. The effect of the galls on plant growth is uncertain. Plants showed dead leaves on the galled node, deformed new stems growing from the galled node and some dead stems above the gall. Methods used for the monitoring of this subordinate project included phone calls and e-mails with CSIRO Entomology, Indooroopilly, Australia. Progress reports were prepared and delivered to the funding agency.
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Progress 10/01/08 to 09/30/09
Outputs
Progress Report Objectives (from AD-416) Lippia (Verbenaceae) is a fast-growing, mat-forming weed in Australia, where it was introduced as an ornamental during the second half of the nineteenth century. Biological control is proposed as the sustainable method for this weed, with no records of arthropods associated and few for fungal pathogens. Approach (from AD-416) Collect natural enemies of Lippia; collect and curate flora and fauna specimens; maintain and specimen database; prepare and send specimens for identification; develop methods to propagate and grow Lippia in the laboratory; develop rearing techniques and study the biology of selected natural enemies; and observe host range of specimens in the field and laboratory. Significant Activities that Support Special Target Populations A taxonomic study confirmed that Phyla nodiflora and P. fruticosa are native of Argentina. Molecular studies are being replicated in Australia. The richness of natural enemies compared by species accumulation curves revealed that 64-90% of the expected arthropods were detected. Kuschelina bergi A pupation substrate study revealed that emergence of K. bergi varied with the type and condition of substrate. The highest emergence was observed in soil, slightly higher in dry soil and similar to moist sand. With this, we developed a lab culture of 500 individuals after the third generation. Host specificity a. Adult feeding, no-choice. Adults were kept individually in cages with one of the Verbenaceae Phyla canescens, P. nodiflora, P. fruticosa, Lantana megapotamica, Glandularia platensis, G. tenera, and Duranta sp. The plant part exposed for one week was the apical portion of one stem with leaves. Consumption of foliar area was measured and compared. All adults survived on all test plants. However, feeding was only observed on Phyla spp. The highest consumption was on P. canescens with 20% followed by P. nodiflora and P. fruticosa with 10%. b. Larval feeding, no-choice. Starvation test to study the larval development on the plants used above. Development of larvae to pupae and to adults occurred only on Phyla spp. These results revealed that K. bergi is restricted to Phyla species. c. Maternal and pre-adult effect. To predict the risk of K. bergi on P. nodiflora in Australia, we are testing if the maternal and pre-adult host plant influence the fitness and behavior of Kuschelina progeny. We initiated �lines� consisting of 6 groups of 10 newly emerged larvae from a laboratory culture. Each line was randomly assigned to cages with one plant of P. cansecens, P. nodiflora or P. fruticosa. The emerged adults were counted, sexed and a couple placed in plastic containers in a rearing chamber to evaluate fertility and fecundity. The ensuing larvae from each line were separated to study (1) the feeding preference and (2) the larval development on Phyla spp. in relation to the original line. The preference, survivorship, and fecundity of the last generation will be compared considering the host plant of the parental generation. So far, adults have emerged from the three plants; although ~80% emerged from P. canescens and only ~50% from the other Phyla. Observations suggest that feeding was also higher on P. canescens. The experiment is still in progress. Longitarsus spp. Host specificity. We tested the feeding behavior of Longitarsus sp.1 as above by measuring the consumption rate and the number of feeding marks. A significant preference was found for P. canescens and Glandularia on consumption rate; P. canescens and P. fruticosa showed more feeding marks. Methods used for the monitoring of this subordinate project included periodical phone calls and E-mail exchanges with CSIRO-France and CSIRO- Australia. Also, progress reports were prepared and delivered to the funding agency.
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Progress 10/01/07 to 09/30/08
Outputs
Progress Report Objectives (from AD-416) To conduct field surveys and laboratory studies of natural enemies of Lippi (Phyla canescens). Approach (from AD-416) Collect natural enemies of Lippia; collect and curate flora and fauna specimens; maintain and specimen database; prepare and send specimens for identification; develop methods to propagate and grow Lippia in the laboratory; develop rearing techniques and study the biology of selected natural enemies; and observe host range of specimens in the field and laboratory. Significant Activities that Support Special Target Populations Surveys. Exploratory surveys were extended to Bolivia and Chile. In Bolivia, P. reptans was found in 2 sites and little insect damage was found, except some feeding marks similar to Longitarsus�. In Chile, samples were taken for DNA extraction. Plants were found associated to water bodies and in drier areas. They were identified as P. canescens and P. reptans. They differed from Argentine populations in leaf toughness, and colour and shape of the inflorescence. Fauna associated was not found. According to an experiment conducted in Montpellier, France, with plants from France, Australia and Argentina, Argentine plants differed in size and production of flowers. Natural Enemies Longitarsus sp. This flea beetle is distributed along the range of Phyla in Argentina. The rearing lab technique resulted difficult and should be improved. Kuschelina bergi. This insect was associated with plants in the southern distribution of P. canescens. Around 20 adults were collected and reared and approximately 1000 eggs were obtained for a non choice test which is in progress. Field Evaluation. A field experiment was conducted to test the Resource- Enemy Release Hypothesis. The tests consisted of exclusion of natural enemies to evaluate the performance of plants considering the weed competitive ability in relation to the presence or absence of their natural enemies. Aerial and underground parts of the plants were taken to the laboratory and the biomass measured. In addition, insect damage, presence of pathogens symptoms, and soil samples were measured. Analysis is in progress.
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Progress 10/01/06 to 09/30/07
Outputs
Progress Report Objectives (from AD-416) To conduct field surveys and laboratory studies of natural enemies of Lippi (Phyla canescens). Approach (from AD-416) Collect natural enemies of Lippia; collect and curate flora and fauna specimens; maintain and specimen database; prepare and send specimens for identification; develop methods to propagate and grow Lippia in the laboratory; develop rearing techniques and study the biology of selected natural enemies; and observe host range of specimens in the field and laboratory. Significant Activities that Support Special Target Populations Surveys were conducted in four ecological regions of Argentina: (1) Wetland Chaco; (2) Dry Chaco and Yungas; (3) Pampas; and (4) the transition zone between Southern Chaco, Pampas and Patagonia. Phyla sp. was recorded in 57 of 106 sites, mostly east of 66� W, from sea level (Buenos Aires province) up to 2100 m (Volc�n, Jujuy Province). In the northern half of region 2, pure and mixed stands of P. canescens P. poss. reptans, and several intermediate forms (hybrids?), were found. High phenotypic variations and poor key characters made it difficult to discriminate these species in the field. Elsewhere, populations found were easily identified as P. canescens. Recent studies of herbarium specimens in Argentina did not clarify the issue. So far, 21 species of arthropods were found: four beetles, a leaf mining fly, two thrips, two micro moths and two hairy caterpillars, eriophyid mites, unidentified stem gallers, four leafhoppers, two Cercopidae and a weevil. Many fungi were found associated with Phyla spp.; some are secondary invaders (Nigrospora, Sordaria, Podospora, etc), others are clearly pathogenic (Puccinia cf. lantanae, Cercospora cf. lippiae, Colletotrichum spp.) and some others have unknown pathobiology (Fusarium sp., Bipolaris sp., Alternaria sp., Phoma sp., Phomopsis sp.). Cercospora cf. lippiae was the most widespread among the parasitic species and causes a necrotic leaf spot which might inflict important damage to the host. There are at least three Colletotrichum spp. involved in leaf spot symptoms; one of them might be a new species. The microcyclic rust (Puccinia cf. lantanae) should be one of the candidates to be studied, but unfortunately the host seems to be Phyla reptans rather than P. canescens. Methods used for the monitoring of this subordinate project included periodic phone calls and e-mail exchanges with Mic Julien (CSIRO Entomology European Laboratory, Montpellier, France). Also, three quarterly reports were prepared and delivered to the funding agency.
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Progress 10/01/05 to 09/30/06
Outputs
Progress Report 4d Progress report. Lippia (Phyla canescens). Reimbursable Cooperative Agreement (Project Number 0211-22000-005-04T with CSIRO, Canberra, Australia, started in April 2006. It is native to South America, introduced into Australia as an ornamental in late nineteenth century and now considered a major threat to biodiversity, riparian areas, conservation and grazing systems. This weed does not generally respond to herbicide or grazing management causing an annual cost of 1 billion dollars in 5.3 million hectares; additionally, it is responsible for high erosion risk for floodplains. This whole project includes research in genetics and taxonomy. The aim is to determine the centre of origin and native range of the weed and to search for biological control agents. The arthropod search is being conducted by SABCL, while plant pathogens by Guadalupe Traversa, PhD student, Universidad Nacional del Sur, Bahia Blanca, Argentina. Surveys. First surveys ever conducted
included central, west, east and northern Argentina in areas selected according to herbarium records. The weed was recorded frequently in the Chaco Region and Pampas. Plants collected at several sites are being cultivated in the greenhouse waiting for blooming and identification. Arthropods: Four leafhoppers (Cicadellidae), four beetles (Chrysomelidae) , a leafmining fly (Agromyzidae), two thrips (Thysanoptera), eriophyd mites and unidentified stem gallers. Some of them are being reared in the laboratory to study their biology and preliminary host specificity. Pathogens: The analysis revealed the presence of at least 12 different fungi. Other materials collected are currently under study. So far, Cercospora cf. lippiae (widespread and damaging) and Colletotrichum spp. appear promising.
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