Aplopsora corni sp. nov. onCornus controversa from Hokkaido,Japan

Aplopsora corni sp. nov. is proposed for a rust fungus whose uredinial and basidial stage occurs onCornus controversa (Cornaceae) in Hokkaido. This new species is separated by its larger urediniospores and probasidia from the morphologically closely relatedA. nyssae onNyssa aquatica andN. sylvatica (Cornaceae) distributed in southern North America.     

Phylogenetic analyses of <Emphasis Type="Italic">Uromyces viciae-fabae</Emphasis> and its varieties on <Emphasis Type="Italic">Vicia</Emphasis>, <Emphasis Type="Italic">Lathyrus</Emphasis>, and <Emphasis Type="Italic">Pisum</Emphasis> in Japan

A pea rust fungus, Uromyces viciae-fabae, has been classified into two varieties, var. viciae-fabae and var. orobi, based on differences in urediniospore wall thickness and putative host specificity in Japan. In principal component analyses, morphological features of urediniospores and teliospores of 94 rust specimens from Vicia, Lathyrus, and Pisum did not show definite host-specific morphological groups. In molecular analyses, 23 Uromyces specimens from Vicia, Lathyrus, and Pisum formed a single genetic clade based on D1/D2 and ITS regions. Four isolates of U. viciae-fabae from V. cracca and V. unijuga could infect and sporulate on P. sativum. These results suggest that U. viciae-fabae populations on different host plants are not biologically differentiated into groups that can be recognized as varieties.Contribution no. 184, Laboratory of Plant Parasitic Mycology, Institute of Agriculture and Forestry, University of Tsukuba, Japan     

Rust fungi (Uredinales) found in Marshall Islands and Pohnpei

Uromyces wedeliae, Coleosporium plumeriae, andUredo guettardae are reported for the first time from Kwajalein Atoll, Republic of Marshall Islands, and Pohnpei, Federal States of Micronesia.     

Caeoma tsukubaense n. sp., a rhododendron rust fungus of Japan and southern Asia, and its relationship to Chrysomyxa rhododendri

A rust fungus found in Japan on Rhododendron kaempferi, R. kiusianum, and R. dauricum has previously been identified as Chrysomyxa rhododendri. Light and scanning electron microscopy of fresh and herbarium materials of the rust fungus, however, show that the spore surface morphology differs from the urediniospores of C. rhododendri, and the spores are slightly smaller. Furthermore, the DNA sequence of the 5′-end of the large subunit of ribosomal DNA differs from that of C. rhododendri by 3%. Telia have not been found; therefore, it is redescribed as a new anamorphic species, Caeoma tsukubaense. Several specimens from North Korea, Tibet, and Nepal bearing a similar rust fungus are also included in the species.Contribution no.193 from the Laboratory of Plant Parasitic Mycology, Graduate School of Life and Environmental Sciences, University of Tsukuba, Japan     

Morphological and phylogenetic analyses of <Emphasis Type="Italic">Uromyces appendiculatus</Emphasis> and <Emphasis Type="Italic">U. vignae</Emphasis> on legumes in Japan

Uromyces appendiculatus, inclusive of three varieties, is distinguished from U. vignae primarily by the position of urediniospore germ pores and putative host specificity. However, opinions concerning these morphological and physiological features as taxonomic characters have varied greatly, and distinction of these species has often been confused. To clarify the taxonomy of these two species, morphological features of urediniospores and teliospores of 225 rust fungus specimens on species of Phaseolus, Vigna, Apios, Lablab, and Dunbaria were examined by light microscopy and scanning electron microscopy. Forty-five specimens were subjected to molecular phylogenetic analyses. As a result, the position of germ pores in urediniospores and the teliospore-wall thickness were considered as good characters to separate three morphological groups. In molecular analyses, the specimens fell into two and three clades based on the nucleotide sequence at D1/D2 domain of LSU rDNA and ITS regions, respectively. One of the D1/D2 clades corresponded to one morphological group whereas another D1/D2 clade included two other morphological groups. In contrast, each of the three ITS clades corresponded to a separate morphological group. Neither morphological groups nor molecular clades were host limited. It is suggested that the three morphological groups that corresponded to three distinct ITS clades constitute distinct species.Contribution no. 186 from the Laboratory of Plant Parasitic Mycology, Institute of Agriculture and Forestry, University of Tsukuba, Japan     

Volatile terpenoids from aeciospores of Cronartium fusiforme

Aeciospores of Cronartium fusiforme isolated from slash pine (Pinus elliottii) trees were analyzed for volatile terpenoids by GLC and GLC-MS. α-Pinene, β-pinene, Δ³-carene, myrcene, linonene, β-phellandrene, and δ-terpinene were the major monoterpenoid hydrocarbons present with only traces of camphene. A number of monoterpenoid alcohols were also present of which terpinen- 4-ol predominated. Among the various acyclic sesquiterpenes present, β-farnesene and β-citronellol were identified. Several aromatic compounds were also observed, including o-cresol.     

From the laboratory to the field: contrasting effects of multi-trophic interactions and agroforestry management on coffee pest densities

Only few factors influencing pest populations can be studied in the laboratory, but many population‐driving factors interact in the field. Therefore, complementary laboratory and field approaches are required for reliable predictions of real‐world patterns and processes. Laboratory and field experiments with the red spider mite, Oligonychus ilicis McGregor (Acari: Tetranychidae), and the coffee leaf miner, Leucoptera coffeella Guérin‐Méneville (Lepidoptera: Lyonetiidae), on coffee plants, Coffea arabica L. (Rubiaceae), were combined to study the relative importance of biotic interactions, including resource preferences and natural‐enemy impact, and habitat factors, such as agroforestry type and management intensity, on coffee pest densities. In the laboratory, leaf discs cut from undamaged coffee plants were significantly preferred by red spider mites over those from plants infested with conspecific mites, leaf rust pathogens [Hemileia vastatrix Berkeley & Broome (Uredinales)], or coffee leaf miners, resulting in higher reproductive success. Similarly, undamaged plants were preferred by coffee leaf miners over red spider mite‐infested plants. However, in the field, red spider mite densities were positively correlated with coffee leaf miner and leaf rust densities, thereby contrasting with laboratory predictions. Hence, our study suggests that the importance of resource preferences and fitness expected based on laboratory experiments was suppressed by environmental conditions in the field, though other unassessed biotic interactions could also have played a role. Furthermore, intensified agroforestry was characterized by higher red spider mite densities, whereas densities of its major natural enemy, the predatory mite Amblyseius herbicolus Chant (Acari: Phytoseiidae), were not related to agroforestry management. Densities of coffee leaf miner and its main natural enemy, a eulophid parasitoid (Hymenoptera), were not affected by management practices. In conclusion, patterns found in the laboratory did not hold for the field, emphasizing the difficulties of extrapolating small‐scale experiments to larger spatial scales and the need to combine both approaches.     

Supplemental risk evaluations of Puccinia jaceae var. solstitialis for biological control of yellow starthistle

Additional tests of native North American Cirsium species, Saussurea americana, and modern safflower cultivars (Carthamus tinctorius) were requested by regulators and specific interest groups during the risk assessment of foreign isolates of Puccinia jaceae var. solstitialis for biological control of yellow starthistle (YST, Centaurea solstitialis) in the United States. These tests supplement an earlier, extensive host range determination that established P. jaceae from YST as generally host specific and potentially useful for biological control. The additional research was in response to potential hazards identified in an earlier study, changes in safflower cultivars, and concern that P. jaceae might cause a safflower seedling disease similar to hypocotyl infections from infestation by Puccinia carthami teliospores. S. americana, a close relative of yellow starthistle, had not been tested previously. All tests were conducted in a containment greenhouse. Foliage of 19 Cirsium species, 11 safflower cultivars, and S. americana was inoculated with urediniospores and subjected to a 16-h dew period at 18–20 °C. Neither the Cirsium species nor S. americana became infected after foliar inoculations. Compared to foliar infections by P. carthami from safflower in California, only minor infections developed from inoculations with P. jaceae. These were similar to infections observed in earlier studies, and it was not possible to maintain P. jaceae under optimal greenhouse conditions on safflower foliage. Quantitative teliospore inoculations with P. jaceae did not cause infection on safflower hypocotyls, even though large cankers occurred on plants inoculated with P. carthami teliospores. Clear microscopic evidence of infection also was observed in hypocotyls inoculated with P. carthami. These data suggest that native (including rare, threatened, or endangered) Cirsium spp., modern safflower cultivars, and S. americana are not likely to be adversely affected by the use of P. jaceae for biological control of YST. Results from these studies substantiate previous findings and were incorporated in a proposal for permission to use P. jaceae for YST control in California.     

Deciphering species complexes: Puccinia andropogonis and Puccinia coronata, examples of differing modes of speciation

Species of macrocyclic, heteroecious grass rusts often have been defined with wide host ranges and variation in spore morphology. Consequently, some are species complexes and contain genetically distinct forms. Molecular analyses, together with morphological and biological methods, provide powerful means to dissect these complexes. Puccinia coronata is a complex species that has a broad telial host range including more than 45 genera of grasses and a narrow aecial host range. Phylogenetic analysis of nuclear ribosomal internal transcribed spacer (ITS) DNA sequences from 15 aecial and telial collections grouped P. coronata into six distinct clades supporting separation of this complex into four distinct species. Puccinia andropogonis, a common rust of tall prairie grasses in North America, is also a complex species. However, in contrast to P. coronata, P. andropogonis has a narrow telial host range and a broad aecial host range. DNA sequence analysis grouped 15 collections of P. andropogonis into six distinct clades representing at least four distinct species. Speciation of P. coronata appears to have occurred primarily by radiation onto new telial hosts, whereas in P. andropogonis speciation appears to have occurred primarily by radiation onto new aecial hosts.