Molecular phylogeny suggests a close relationship of Asteraceae to the early evolution of Golovinomyces. The family Asteraceae, with a geographic origin in South America, expanded into the Northern Hemisphere, where it may have been infected by an ancestor of Golovinomyces, thus starting a close hosteparasite relationship. Using this event as a calibration point, we designed molecular clocks fo...

Downy mildew, caused by Peronospora parasitica Pers. ex Fr., is an important disease of canola that has implications during early seedling establishment. The fungus invades young seedlings and severe infection results in premature defoliation. In worst cases, the systemic infection may even kill the seedlings. Current commercial varieties of canola are very susceptible to downy mildew. Therefor...

I. The Importance of Powdery Mildews. . . . . . . . 51 II. Life Cycle of Powdery Mildews . . . . . . . . . . . . . 53 A. Asexual Reproduction. . . . . . . . . . . . . . . . . . 53 B. Sexual Reproduction . . . . . . . . . . . . . . . . . . . 53 III. Interactions with the Host Plant . . . . . . . . . . . . 55 A. Influence on Host Metabolism. . . . . . . . . . . 56 B. Induced Susceptibility and Re...

Zhang, S. P., Liu, M. M., Miao, H., Zhang, S. Q., Yang, Y. H., Xie, B. Y., Wehner, T. C., and Gu, X. F. 201_. Chromosomal mapping and QTL analysis of resistance to downy mildew in Cucumis sativus. Plant Dis. 9_:XXXX-XXXX. Downy mildew of cucumber (Cucumis sativus L.), caused by Pseudoperonospora cubensis (P. cubensis), is a major foliar disease worldwide. The cucumber inbred lines K8 (resistant...

Hortic. bras., v. 27, n. 1, jan.-mar. 2009 The Northeast region of Brazil responds for nearly 95% of the national melon (Cucumis melo L.) production. Located at this region, States of Rio Grande do Norte and Ceará supply respectively 55 and 28% of the total melon harvested in Brazil (FNP, 2007). The expansion of the area used for melon production in this region, in addition to an intensive year...

Mycologists and practicing dermatologists frequently have designated as distinct species the downy forms of Trichophyton mentagrophytes that are commonly isolated from chronic ringworm of the feet or toenails and the granular forms of this fungus usually isolated from suppurative ringworm of the beard or scalp. The chief difference between the two types of culture is one of gross colonial form....

Pseudoperonospora cubensis, an obligate biotrophic oomycete causing devastating foliar disease in species of the Cucurbitaceae family, was never reported in seeds or transmitted by seeds. We now show that P. cubensis occurs in fruits and seeds of downy mildew-infected plants but not in fruits or seeds of healthy plants. About 6.7% of the fruits collected during 2012-2014 have developed downy mi...

Three species of woodpeckers (Piciformes: Picidae) in Manitoba, Canada, were examined for chewing lice (Phthiraptera): the resident downy woodpecker (Picoides pubescens (Linnaeus), n = 55), and two migrants, yellow-bellied sapsucker (Sphyrapicus varius (Linnaeus), n = 316) and northern flicker (Colaptes auratus (Linnaeus), n = 225). Six species were collected: Menacanthus pici (Denny) (Amblycer...