Key points are not available for this paper at this time.
SUMMARY A selection of fungicides, herbicides and surfactants and urea were tested for their effect on the production of pseudothecia and ascospore release of Leptosphaeria maculans present on oil‐seed rape straw and turnip seed crop straw. The fungicides ethyl mercury phosphate, triarimol, fenarimol, carbendazim, tridemorph and benomyl, each at 1 g/litre, the herbicides dinoseb and diquat, each at 10 g/litre the surfactants Bradasol, Cetrimide, Deciquam 222, Hyamine 1622 and Maxonol N, each at 50 g product/litre, and urea at 150 g/litre, applied to straw before pseudothecia had formed were more than 90% effective in preventing further development. These chemicals were also effective in preventing further ascospore production when applied to straw bearing mature pseudothecia but only dinoseb and urea prevented the release of mature ascospores. The results suggest that it may be possible to break the life cycle of L. maculans by chemical treatment and thereby obviate the need for subsequent control measures.
HUMPHERSON‐JONES et al. (Thu,) studied this question.