Development of Dothistroma pini Upon and Within Needles of Austrian and Ponderosa Pines in Eastern Nebraska

Signaling for Infection Structure Formation in Fungi

“…These effects were enhanced when the leafs environment was interrupted with a dry period. Peterson and Walla (1978) noted a similar hydrotropism of a needle blight pathogen (Dothistroma pim) toward pine stomata. They surmised that another pine pathogen, Scirrhia acicola, also behaved hydrotropically.…”

A review of Pinaceae resistance mechanisms against needle and shoot pathogens with a focus on the Dothistroma–Pinus interaction

“…Similarly, Woo et al (2001) observed that Pinus monticola Douglas ex D. Don families susceptible to WPBR had wider and larger stomata. Conversely, Peterson and Walla (1978), probably working with D. pini, found that the number of stomata did not vary between resistant and susceptible P. nigra and P. ponderosa needles or between needle bases and tips, despite more symptoms observed at the tips.…”

“…With free water available, Dothistroma conidia are released from conidiomata and disperse by water splash, throughout the growing season (Gibson et al 1964;Thyr and Shaw 1964;Peterson 1967Peterson , 1973Gadgil 1977;Rack 1986;Karadžid 1989;Boateng and Lewis 2015). Conidia germinate within 3 days at an optimum temperature of between 17 and 22°C (Gibson et al 1964;Gadgil 1967;Ivory 1967) producing numerous germ tubes, which have been observed growing randomly on the needle surface (Gadgil 1967;Ivory 1972;Peterson and Walla 1978;Muir and Cobb 2005) as well as directly towards stomata (Peterson and Walla 1978;Muir and Cobb 2005). Simple germ tubes penetrate needles through stomata and grow in stomatal cavities (Ivory 1972;Muir and Cobb 2005;Kabir et al 2014).…”

“…Intercellular hyphae grow locally from the site of infection, in mesophyll tissue (Gadgil 1967;Ivory 1972;Peterson and Walla 1978;Kabir et al 2014), resin canals (Gadgil 1967;Peterson and Walla 1978), endodermal cells (Gadgil 1967;Peterson and Walla 1978) and transfusion and vascular tissues (Peterson and Walla 1978). Gadgil (1967) and Peterson and Walla (1978) also observed intracellular hyphae in the mesophyll and transfusion and vascular tissues. Eventually, erumpent conidiomata will form in lesions, and conidia are released.…”

“…This work included investigations into the infection and disease development processes on Pinus nigra J.F. Arnold and Pinus ponderosa Douglas ex C. Lawson (Peterson and Walla 1978). Research in the western regions of North America, including that of Cobb (Cobb and Libby 1968;Cobb and Miller 1968;Muir and Cobb 2005), Parker (Funk and Parker 1966;Parker and Collis 1966), and Thyr and Shaw (1964), was most likely on D. septosporum, as this is the only Dothistroma species confirmed using molecular methods in this region.…”