§ Mr. Eldon Griffithsasked the Minister of Agriculture, Fisheries and Food what evidence he has from the national vegetable research stations that alternaria leaf fungus is being transmitted from ripe crops of rape to cauliflowers, cabbage and sprouts by way of combine harvesters used to harvest rape; what sprays are effective against alternaria; and if he will offer advice to farmers whose crops may be affected.
§ Mrs. FennerIn general, the significant spread of alternaria from oil seed rape to vegetable brassicae has been observed only for brassica seed crops in Essex. Nevertheless, the national vegetable research station has evidence that when infected oil seed rape is combined, clouds of alternaria spores are generated which could infect vegetable brassicae downwind. Alternaria can also spread, however, at other times and the relative importance of spread from combine harvesters is not known.
Chlorothalonil sprays are effective and other promising fungicides are being investigated. On the few occasions when vegetable brassicae are considered at risk, they should be sprayed if the weather is wet or humid and if they are within half a mile of a heavily diseased oil rape crop that is being combined.