Irrigation applied early during tuberization significantly decreased scab on tubers of Majestic, King Edward and Record, but not on Pentland Crown, a resistant cultivar, where tubers had little scab even from the driest soil. There was little benefit from keeping soils wetter than 0.6 in (15.24 mm) soil moisture deficit (s.M.D.) for more than 3 weeks after tuber initiation, and irrigation to 0.8 in (20.32 mm) S.M.D. gave economic control. Irrigating only after the 'marble stage' increased yield but the tubers were scabbed. Irrigation did not alter the rate eyes (nodes) separated from the apical bud but speeded the swelling of tubers.

Isolates of Fusarium were obtained from samples of barley grain at harvest in 1971, 1973 and 1974. The ability of these isolates to produce the mycotoxin zearalenone was examined, the grain also being tested for its presence in 1974. The most common isolate was F. culmorum, 60% of which in 1974 produced zearalenone. Other species isolated which produced this mycotoxin were F. moniliforme, F. graminearum, F. avenaceum, F. nivale and F. sambucinum var coeruleum, the last three species have not previously been recorded as producing zearalenone.

No abstract

SUMMARY A surely of 174 fields showed that take‐all was the major disease affecting yield when two or more successive crops of winter wheat were grown. The eyespot‐resistant cultivar Cappelle Desprez comprised more than 90 per cent of the acreage and this may be a factor reducing the incidence of eyespot under this type of cropping. The effect of husbandry practices such as previous cropping, date of sowing, and the time interval between ploughing and sowing, were examined in relation to the incidence of take‐all. With increasing intensity of cropping there was an increase in the amount of nitrogenous fertilizer used but this appeared only to maintain yield in the face of increasing disease. It was possible to establish a limited relationship between the incidence of take‐all at G.S.3 and that present at G.S.10‐5. A highly significant effect of take‐all at G.S.10‐5 on yield was established.

Twenty-six Puecilomyces spp. isolated from silage in the UK were tested in a potato dextrose broth for the ability to produce the mycotoxin patulin. Of the 26 isolates 21 were shown to be capable of producing patulin. The ability of such isolates to produce patulin does not seem to be influenced by the grass species ensiled nor the pH of the silage. Patulin was not detected in any of the silage samples.