The ecology of skeleton weed (Chondrilla juncea) in Western Australia, seed pools and seedling establishment in pennyroyal (Mentha pulegium), regeneration of Afghan thistle (Solanum hoplopetalum)

To assess the viability of seed produced under natural conditions. To determine the size of seed banks in different areas and to determine when seedling establishment occurs on a seasonal basis. To assess the relative contribution of reproduction by seed and root fragments to the persistence and growth of populations. To determine if reproduction from root fragments occurs more readily at certain times of the yea

The ecology of skeleton weed (Chondrilla juncea) in Western Australia, Demographic aspects of wild radish (Raphanus raphanistrum) populations in lupin crops and Identification of populations of mesquite (Prosopis spp) from the West Pilbara region.

To determine what forms of skeleton weed are present in Western Australia and to map their respective distribution. To determine, on the basis of climatic characteristics, the suitability of various areas within the Western Australian wheatbelt for infestation by skeleton weed. To determine the amounts, viability and dormancy status of seeds produced by field-grown plants during summer and autumn months. To determine the effectiveness of conventional tillage practices in limiting establishment of skeleton weed seedlings. To determine the regularity with which seedling establishment occurs under field conditions and how the probability of establishment is affected by the time of germination. To follow the fates of plants which establish from experimental sowings. To determine patterns of emergence, seedling survival and reproduction of wild radish in dry and wet-sown lupin crops in relation to cultivation and herbicide treatments. To establish the identities of two Western Australian populations of mesquite (Prosopis), by comparison with taxa of known identities, using the technique of starch gel electrophoresis. This information will be: required should biological control of mesquite be attempted

The ecology of skeleton weed (Chondrilla juncea) in western Australia. Survival and fecundity of wild radish (Raphanus raphanistrum) populations in lupin crops. Reproduction and seed persistence in Arum lily (Zantedeschia aethiopica).

After ripening and fates of field-stored skeleton weed seeds, 86BA11. Predation on seeds of skeleton weed, 86BA10. The effects of wetting/drying cycles upon the fates of skeleton weed seeds, 84PE42. Skeleton weed demographic studies, 84BA17. Radish control in lupins, 86N085. Seed production and seed persistence in Arum lily, 86PE56. Germination studies on fresh and stored seeds of Arum lily, 86PE57

Ecology of skeleton weed (Chondrilla juncea) in Western Australia

For the first time a laboratory for conducting this type of research has been established in South Perth, and it has been possible to type plants from mature leaf material. This obviates the necessity of waiting for plants to seed to be able to identify them. A total of six new collections were identified as belonging to either the broad-leaf or narrow-leaf forms, the locations for which are given in Table l.l.. Seed viability. To determine the amounts, viability and dormancy status of seeds produced by field-grown plants during summer and autumn months. Time course of seed production by field-grown skeleton weed plants during 1983/84 - North Miling, Moorine Rock, Merredin, Narembeen. Germination under simulated rainfall conditions. In a pot experiment, both surface-sown and buried (1 cm) seeds were exposed to different total amounts of simulated rainfall then protected from drying for periods of 24, 48 or 72 hours. Following this, pots were placed outside under conditions of high evaporative demand until totally dry. Seed populations were then retrieved and their fates determined. Summer rainfall characteristics for various sites in the western Australian wheatbelt. To characterize the patterns of summer rainfall and to link these with experimental measurements of germination response to simulated rainfall, in order to predict the probabilities of seed pool depletion in different sites

Ecology of skeleton weed (Chondrilla juncea) in WA. Population studies on pennyroyal (Mentha pulegium).

The ecology of skeleton weed - Cunderdin, Tammin, Narembeen (2 sites), Chapman valley, Eradu, East Badgingarra, Moorine Rock. Fate of buried seeds: Chapman, Merredin, Esperance Research stations. Population studies on pennyroyal: Seed production - Denmark, Mount Barker, Frankland. Sizes of seed banks of pennyroyal in pasture and ruderal situations – Denmark, West Denmark, Karri Heights, Narrikup (1), Frankland River. Ruderal populations – Mt Barker (1), Frankland, William bay, East Denmark, Narrikup (2), Denbarker, Mt Barker (2). Seedling emergence and survival – Denmark, Mt Barker, Frankland. Genetic differences between populations

Skeleton weed : how serious a threat in Western Australia?

Skeleton weed is probably the most serious weed ever to threaten the Australian wheat industry. It interferes with wheat cropping at two stages: through competition with the growing crop, particularly for nitrogen and water during the crop\u27s development: and later through the production of a tall, wiry flowering stem which tangles in harvesting machinery and can make harvesting difficult, if not impossible. The weed is a major problem in eastern Australia although a combination of cultural, chemical and biological control programmes is helping to reduce its impact. In Western Australia, skeleton weed is being contained mainly by eradication efforts. Weed Agronomy Research Officers, F.D. Panetta and J. Dodd, are studying the ecology of skeleton weed to determine why it hasn\u27t spread further and how current control methods can be more effectively applied

The potential for skeleton weed

Since its introduction into Australia during the 900s skeleton weed has become one of the most economically significant weeds. Its presence in cereal crops in south-eastern Australia has caused suvere yield reductions and harvesting problems. Skeleton weed was first found on a Western Australian farm in 963. Since then it has been the subject of an intensive eradication campaign organised by the Agricultural Protection Board and funded by an annual levy on wheat growers. Such campaigns, which rely mainly on volunteer searchers, do not exist in eastern Australia because the weed is so widespread it would be impossible to eradicate. Studies conducted by the Weed Agronomy research officers, FD Panetta and J Dodd have led to a greater understanding of the biology and porential of skeleton weed in Western Australia. The following article is a sequel to their earlier article in the Journal of Agriculture (Panetta and Dodd 1984) and assesses what influences the establishment and spread of skeleton weed in this State

Demographic responses to the chemical control of Doublegee

Control of Doublegee in medic pasture, 88WH47. Competitive effect and response of Emex australis in a grazed animal pasture

The ecology of skeleton weed in Western Australia. Survival and reproduction of wild radish populations

1.1 Skeleton weed demographic studies (84BA17) To determine potential growth rates of skeleton weed populations on contrasting soil types. 2.1 Wild radish demography in lupin crops (87GE86) - the results are missing in the report please see in supplementary conten

The demography of doublegee. Ecological studies on Arum Lily.

3.1 Growth of doublegees under summer irrigation. (87A40) The weevil, Perapion antiquum is a potential biological control agent of doublegee. However, it exhibits large population crashes during the summer months in the summer-dry areas of the Western Caped of South Africa, where it is native. It has been suggested that one means of successfully establishing Perapion in Western Australia could be to maintain populations in \u27oases\u27 over the summer months. The aim of this experiment was to determine how readily doublegee could be maintained in a non-senescent phase under irrigated and shaded conditions. 3.2 Doublegee demography in cereal crops (87GE30) To measure reproductive output of late-emerging doubegee plants in comparison with those which survive or avoid herbicide application. 4.1 Effect of time of spraying on seed production of Arum Lily (87PE8) To determine the latest time to apply chlorsulfuron without permitting the production of viable seeds