John Hubert Craigie was descended from Scottish crofters. His grandfather, William Craigie, the son of Hugh Craigie of Rousay, was born on Rousay, Orkneys, in 1810, and died in Canada in 1901. Life was difficult in Scotland early in the 19th century. Like many of his fellow Orkneymen, William Craigie emigrated to Canada as an indentured employee of the Hudson’s Bay Company, probably in the 1830s. In the course of his duties he crossed Canada two or three times, travelling out of York Factory on Hudson Bay. The family oral history is that William could not abide the way the Company treated native peoples; factors were expected to ply the natives with liquor and then ‘purchase’ furs for a pittance. As an ‘indentured servant’ he would be in mortal danger from the colonial authorities if he tried to leave, but he took an opportunity to escape via the USA and returned home to the Orkneys. There he married Jean Mainland. Because they could not get permission to marry on Rousay, they eloped by rowboat to be married in another village. William and Jean later emigrated to Canada, reaching the port of Pictou, Nova Scotia, in June 1842 after sailing on the barque Superior for 51 days from Thurso, Caithness.

(2006). Rene-O. Lachance (1909–1992) Canadian Journal of Plant Pathology: Vol. 28, No. sup1, pp. S34-S34.

Race 1 (race 0 according to new international designation) of sunflower rust (Puccinia helianthi) remained dominant in the rust population for years after cultivars carrying the R1 gene conferring resistance were commonly grown, even though race 3 (0, 1), which is able to overcome R1, was present in nature when cultivars with R1 were first released. A mixture with originally equal proportions of races 1 and 3 was maintained for eight spore generations on line CM 303 susceptible to both races. Race 1 increased from 41% in the 1st generation to stabilize at 95% by the 5th. Factors that might contribute to the apparent greater fitness of race 1 under controlled conditions, including germination percentage of spores on the leaf surface, growth rate of germ tubes, formation of appressoria, size of mycelial colonies within leaves, size and density of pustules on leaves, and spore production, were compared. The critical factors appeared to be the higher germinability, more rapid germination, and more rapid formation of appressoria by spores of race 1.

Verticillium wilt (Verticillium dahliae Kleb.) is a major disease of sunflowers (Helianthusannuus annuus L.), one of the world’s most important sources of edible vegetable oil (Putt 1978; Sackston 1981; Zimmer and Hoes 1978). New strains of the pathogen able to attack previously resistant cultivars have appeared (Bertero and Vazquez 1982), making it necessary to utilize new sources of resistance, and advisable to investigate other methods of control.

An early and a midseason cultivar of Jerusalem artichoke (JA) (Helianthus tuberosus) were better adapted than a late cultivar at Macdonald College and L’Acadie, Quebec, and Ottawa, Ontario. Diseases observed on JA were powdery mildew (Erysiphe cichoracearum), Sclerotinia rot (S. sclerotiorum), and apical chlorosis (Pseudomonas syringae pv. tagetis).Key words: Jerusalem artichoke, Helianthus tuberosus, adaptability, powdery mildrew, Sclerotinia rot, apical chlorosis

Sunflower, the second most important oilseed crop in the world, was developed as a crop in eastern Europe, but is a native of North America. The pathogens causing many of its major diseases are also native to North America. Although a profitable crop, sunflowers have fairly low value per hectare. Disease control must, therefore, be inexpensive, by resistant varieties or seed treatment or cultural practices, rather than repeated field application of chemicals. Rust, a limiting factor in many countries, has been successfully controlled everywhere by resistance from wild sunflowers discovered in Canada about 1950. New races are posing problems in Argentina and Australia, but new resistance may be available. Verticillium wilt has been destructive in some areas but resistance is available from wild sunflowers and Russian high-oil varieties. Downy mildew, highly destructive in many countries, has been effectively controlled by two genes from the original rust-resistant material. A new race attacking this resistance was discovered in 1980: resistance to it appears to be available. Sclerotinia stalk rot and head rot, caused by a pathogen with wide host range, is much harder to control by breeding. Leaf spot diseases have long been a limiting factor in some European countries and elsewhere, but were considered minor in North America until recently. Broom rape, a root parasite which almost destroyed the crop in the USSR and elsewhere in eastern Europe, does not attack it in North America. It is controlled by resistant varieties.

(1980). Some factors influencing infection of sunflower seed by Verticillium dahliae. Canadian Journal of Plant Pathology: Vol. 2, No. 4, pp. 209-212.

Lupinus albus L. inoculated at 6 weeks and L. luteus L. at 11 weeks by stem injection with a spore–mycelium suspension of Verticillium albo-atrum Reinke and Berth. produced 2.5 and 6.8% infected seeds, respectively. Other methods of inoculation failed to produce seed infection. The pathogen was present internally in infected seeds of L. luteus, but in L. albus it was superficial. Histological observations indicated that plugs of amorphous material in infected vessels, and branching of the vessels, may serve as barriers to seed infection. Even the low levels of seed infection observed may have economically significant epidemiological implications.

Stem elongation of sunflower plants inoculated at the two-leaf stage through apical buds with Plasmopara halstedii was greatly inhibited. Systemically infected plants did not show normal phototropic and negative-geotropic responses. There was a positive correlation between stunting of infected plants and ability of stem slices to remove indoleacetic acid (IAA) from test solutions. IAA disappearance in the presence of stem slices of infected plants was also highly correlated with area of mildew symptoms on leaves. Although IAA disappeared in the presence of all diseased tissues, leaf tissues were least active. No IAA disappeared in the presence of sporangia of the pathogen. These results explain reduced levels of IAA observed in mildew-infected sunflowers in earlier studies and may account for the characteristic stunting of systemically infected plants.

Sunflowers bud-inoculated with Plasmopara halstedii became systemically infected with downy mildew and produced infected seeds at 15 to 30 °C. Oospores were observed in seeds of inoculated and also naturally infected plants from the field. Infected seeds gave rise to symptomless plants. Infected seeds proved effective as inoculum, inducing infection in 14 to 89% of the plants inoculated at 20 °C. Most of the infections (80%) were symptomless (latent).Systemic infection occurred, but latent infection was more frequent, in plants grown in soil containing debris of mildewed plants. Latent infection also occurred in uninoculated plants through belowground contact with systemically infected plants. Seed produced by plants with latent infection may carry the pathogen, and may give rise to more plants with latent infection, accounting for widespread dissemination of the disease before plants with typical symptoms are observed.

Systemic infection of sunflowers by Plasmopara halstedii occurs much more readily through hypocotyls than through roots, and through apical buds than through leaves.Systemic symptoms rarely develop from belowground infections of plants past the four-leaf stage, and from apical bud infections of plants past the eight-leaf stage. Necrotic lesions may occur and the pathogen may sporulate on hypocotyls and roots of plants with no typical systemic symptoms.Infection by sporangia produces local lesions in young leaves; some of these infections may become systemic.Immersion of 3-day-old seedlings in inoculum for 1 min resulted in some infection; highest infection resulted from 3- to 6-h exposure.Systemic infection resulted from apical bud inoculation with suspensions averaging one sporangium per plant.Optimum temperature during inoculation of 3-day-old seedlings was 15°, and during incubation was 20° to 25 °C. Optimum temperature during bud inoculation was 15°; incubation temperatures from 15° to 25 °C gave essentially similar results.

Sclerotium bataticola forms appressoria on the epidermis of inoculated sunflower seedlings. The appressoria may aid both mechanical and chemical penetration. Penetration is direct. Penetration of adult plant stems is by mass action of hyphae.Invading hyphae are both intra- and inter-cellular. Longitudinal spread in the cortex is in the intercellular spaces. Hyphae are closely associated with cell walls and the walls of xylem vessels. Vessels are penetrated through the pits.A virulent isolate formed sclerotia on inoculated seedlings within 24 h. An avirulent isolate formed chlamydospore-like resting structures first, and sclerotia later. Sclerotial formation appeared to reflect level of nutrition rather than relationships of isolates.

Symptoms of Verticillium wilt on inoculated plants of the sunflower cultivar Sunrise appeared sooner and were more severe under long days (16 h light, 8 h dark), or short days with interrupted dark period (10 h light, [Formula: see text] dark, [Formula: see text] light, [Formula: see text] dark), than under short days (10 h light, 14 h dark). Uninoculated control plants flowered in 45 to 47 days under short-day conditions, but reached only the yellow bud stage in 50 to 55 days under long days or short days with interrupted dark period. Development of Verticillium wilt of sunflower is not dependent on the initiation of flowering as it is in some other hosts.