In Australia, pyrethrum (Tanacetum cinerariifolium) is affected by a foliar disease complex that can substantially reduce green leaf area and yield. Historically, the most important foliar disease of pyrethrum in Australia has been ray blight, caused by Stagonosporopsis tanaceti, and other fungi generally of minor importance. Temporal fluctuations in the...
The resurgence of cucurbit downy mildew has dramatically influenced production of cucurbits and disease management systems at multiple scales. Long-distance dispersal is a fundamental aspect of epidemic development that influences the timing and extent of outbreaks of cucurbit downy mildew. The dispersal potential of Pseudoperonospora cubensis appears to be limited...
Knowledge of processes leading to crop damage is central to devising rational approaches to disease management. Multiple experiments established that infection of hop cones by Podosphaera macularis was most severe if inoculation occurred within 15 to 21 days after bloom. This period of infection was associated with the most pronounced...
Carpogenic germination of sclerotia and infection of flowers by ascospores of Sclerotinia minor is rare and seldom documented in most hosts. During 2007–2009, S. minor isolates were obtained from surface-sterilized pyrethrum flowers collected from fields in Australia. The isolation frequency of S. minor from flowers in 2007, 2008 and 2009...
Impact and relevance are valued by both plant pathologists and
the supporters of research and extension. Impact has been characterized
as the “So what?” of research results, and in applied research
in agriculture typically involves some change in human
behavior. This might involve, for instance, avoidance of broad
spectrum pesticides,...
Sclerotinia crown rot, caused by Sclerotinia minor and S. sclerotiorum,
is a disease of pyrethrum in Australia that may cause substantial decline
in plant density. The spatiotemporal characteristics of the disease
were quantified in 14 fields during three growing seasons. Fitting the
binary power law to disease incidence provided slope...
The most damaging foliar disease of pyrethrum in Australia is ray
blight caused by Stagonosporopsis tanaceti. The probability of growers
incurring economic losses caused by this disease has been substantially
reduced by the implementation of a prophylactically applied spring
fungicide program. This has been traditionally initiated when 50% of
the...
’Teamaker’ hop (Humulus lupulus L.) (Reg. No. CV-28,
PI 558864) was developed by the USDA-ARS as a unique,
nonbittering, high beta-acids hop and was released on 26 June
2006. The defining characteristics of Teamaker are its near-zero
percent alpha acids levels—a distinctive condition in the Humulus
species (Haunold et al.,...
Hop powdery mildew [Podosphaera macularis (Wallr.) U. Braun & S. Takam.] is best controlled via the production of resistant varieties. Recent evidence supports selection against plant susceptibility genes to fungal pathogens as a more durable resistance mechanism than selection for resistance genes. The objective of this study was to identify...
Disease predictive systems are intended to be management aids. With a few exceptions, these systems typically do not have direct sustained use by growers. Rather, their impact is mostly pedagogic and indirect, improving recommendations from farm advisers and shaping management concepts. The degree to which a system is consulted depends...