Puccinia myrsiphylli

Puccinia myrsiphylli was initially described by Felix von Thümen in 1877. Ethel M. Doidge noted Paul Sydow's 1884 monograph as a resource for this species. P. myrsiphylli was described further in 1926. == Description ==

Puccinia myrsiphylli is a rust fungus with the following characteristics: "Uredospores ellipsoid or sub-globose, pale yellow 30-40 x 26-30 μ; epispore hyaline, about 1.5 μ thick, closely and finely echinulate and with 4-5 scattered germ pores…Teleutospores oblong, cuneate or clavate, apex rounded, acuminate or truncate, usually attenuate at the base, usually gently constricted at the septum, light brown, darker at the apex, 43-70 x 17-28 μ; epispore smooth, about 1.5 μ thick, thickened at the apex (up to 7 μ); germ pores obscure, pedicel short, fragile, hyaline or tinged with brown." This is the spermagonia and pycnia stage of the disease cycle. No other host plants outside of A. asparagoides are required for P. myrsiphylli to complete its life cycle. The researchers in this study found dormant teliospores on extremely diseased cladodes and stems around spring/early summer time in the winter/rainfall region. This suggests that the fungus survives the dry summer months on debris, when above-ground biomass of host plants have stopped growing. It is the thick-walled teliospores that make sure the rust can survive when bridal creeper deteriorates during the summer. P. myrsipjylli recycles each 3–4 weeks during the summer. P. myrsiphylli has two natural enemies: Cecidomyiidae larva and Eudarluca caricis. However, these two enemies do not look like they have a major impact on P. myrsiphylli. == Distribution and habitat ==

Puccinia myrsiphylli is found in Eastern Cape Province in South Africa. == Biological control agent ==

Surveys identified Puccinia myrsiphylli as a possible biological control agent for A. asparagoides, which is also called bridal creeper. Bridal creeper is originally from southern Africa, and has been in Australia since 1871. Surveys were conducted in South Africa to find out if P. myrsiphylli would be able to spread as a possible biological control for A. asparagoides. Between 16 and 20 degrees Celsius is the optimal infection temperature. In addition, a long-term 7-year study has shown decreases in seedling, shoot numbers, and above-ground biomass of A. asparagoides across all sites that were observed (using the biological control agents of the leafhopper and P. myrsiphylli). Some sites recorded greater declines in A. asparagoides on trellises than others due to varying climate and leafhopper factors. Invasive exotic weeds have a negative impact on production and biodiversity. Puccinia myrsiphylli has spread across bridal creeper's range in northern New Zealand. It as an effective biocontrol agent in New Zealand. P. myrsiphylli is seen as a high quality example of effective biological control in New Zealand's 90-year history of weed biocontrol studies. P. myrsiphylli is likely effective by itself, but it has also been tested with other fungal pathogens. For example, it has been tested with Colletotrichum Gloeosporioides. In that test C. Gloeosporioides was only mildly effective on its own. This illustrates that P. myrsiphylli is seen as the most impactful biological control agent in this situation. The Environmental Risk Management Authority of New Zealand was attempting to "de-new" the classification of Puccinia myrsiphylli, which would allow those who use, develop, and manage land in Australia to manipulate P. myrsiphylli for even greater biocontrol effectiveness. ==References==