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Components of partial resistance of two winter wheat cultivars, Maris Huntsman and Maris Ranger, to Septoria nodorum were measured on potted seedlings exposed in the open during the spring and early summer of 1978. The number of lesions 10 days after inoculation was always greater for Maris Ranger than for Marls Huntsman but the relative differences changed during the season: about 10:1 in March, April and May, but only 3:1 in June. The time from infection to first sporulation (latent period) on Marls Ranger was always shorter, especially in March. The percentage leaf area covered by lesions at the end of the latent period was usually greater on Maris Ranger, but variation in the percentage leaf area necrotic at this time did not follow a distinct seasonal trend, nor did cultivars differ in this respect. Twice as many spores per unit area diseased were produced on Marls Ranger as on Maris Huntsman. Seasonal variation in these components could partially be interpreted in terms of the changing weather conditions to which the plants were exposed. [ABSTRACT FROM AUTHOR]

A method is described, using a Czapek Dox V-8 agar and continuous irradiation with near-ultraviolet light, which enables large numbers of spores of Septoria tritici and Septoria nodorum to be produced rapidly and also allows easy identification of the two pathogens by their colony morphology. Also, a simple field inoculation method is described which has proved successful both in experiments involving different inoculum concentrations and for the screening of spring and winter wheat cultivars for their reactions against both pathogens. [ABSTRACT FROM AUTHOR]

Spore suspensions of Septoria nodorum isolated from wheat were used to initiate epidemics on the spring wheat cv. Cardinal and the spring barley cv. Proctor in a field trial. Inoculations were made at g.s.5, 9 and 10.5.4. as separate treatments in wheat and at g.s.5, 9 and 10.3 in barley. A multiple inoculation treatment consisting of all three inoculations was also included. Disease symptoms were much more severe on wheat than on barley both on the leaves and the heads. The largest reductions in 1,000 grain weight were caused by the triple inoculations with decreases of 48 per cent in wheat and 3! per cent in barley. Inoculation at g.s.5 affected only the number of grains and the mean yield per ear and then only in wheat. Fertile tiller number was also reduced by this early inoculation but not significantly. The results are discussed both in relation to the differential reactions of the two hosts and in terms of the epidemiological implications of cross-infection under field conditions. [ABSTRACT FROM AUTHOR]

The article discusses the occurrence of Fusarium redolens in tomato and seed-borne infection. Although tomato wilt caused by F. oxysporum has been known for a long time and seed infection has been demonstrated in the past, outbreaks in the British Isles have been few. This may be because of the lower temperature regimes condition under which crops have been grown. There appears to be no previous record of F. redolens affecting tomatoes in Great Britain. However, in 1965 the fungus was isolated from young plants on a Lancashire, England nursery. Plants about 6 inches tall, growing in two different soils in plastic pots, showed yellowing of the cotyledons and lower leaves and a marked vascular necrosis of the stem from soil level.