Figure captions
Figure 1: Life cycle of poplar rusts in New
Zealand. The smaller inner circle represents polycyclic infection
of poplars by urediniospores, with the potential epidemic period
represented by the bold line, and potential for facultative
overwintering on poplar is represented by the dashed line. Continued
cycling by Melampsora larici-populina during mild winters on
semi-evergreen poplars facilitates earlier build-up of
epidemics. Melampsora medusea can only infect poplar and must
overwinter in the uredinial stage, possibly via mycelia surviving in
leaf buds. The larger outer circle illustrates the full
macrocyclic life cycle of M. larici-populina involving four
additional spore stages in which the pathogen must infect the alternate
host (conifers, primarily larch (Larix sp.)) before the
aeciospore stage can infect poplar and resume the cyclic urediniospore
stage. This figure is based on figures presented in Spiers (1990) and
Vialle et al. (2011). Images of hosts were sourced from the National
Forestry Herbarium, Scion. 2020. NZFRI online dataset.
nzfri.scionresearch.com, accessed in March 2022.
Figure 2 . Flow chart showing expected countervailing influences
of mild climate with semi-evergreen habit in poplar rust pathosystem,
Figure 3. Diagram outlining interplays between factors in the
‘triangle’ involving host plant, pathogen and environment.
Table 1. Expected impacts of alternative poplar rust scenarios on poplar
host [Section 2.3.1.1]