From DENIS OWEN
I, too, am worried about the release of the genetically engineered AcNPV
virus at Wytham and agree that there are questions that require answering;
moreover, I cannot understand why the cabbage looper, Trichoplusia ni, is
claimed as a major pest of cabbages and why the Wytham experiment involves
this species (Focus, 25 June).
In more than forty years of moth trapping I have never encountered Trichoplusia
ni in Britain. Skinner (Colour Identification Guide to Moths of the British
Isles, 1984) writes of this species, ‘An uncommon and irregular visitor,
found mostly in southern England . . . The most favoured years were 1982
(69), 1953 (20), 1968 (16) and 1952 (11). Four feral larvae have been recorded:
two at Portland, Dorset in 1894: on marigold at Teignmouth, Devon, on 18
August 1968; and on sea rocket at Dawlish, Devon, on 25 August 1968.’
Hardly a major pest of cabbages, at least not British cabbages. Indeed
I would rejoice in finding one on the cabbages in my garden.
Denis Owen Oxford Brookes University
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