Abstract
THE glasshcy work of the Experimental and Researh Seaion at Turner's Hill, Cheshunt, Herts, was iijiernipted by enemy action in July 1944; but a bptyntftl amount of laboratory work was carried oujrauringxhat year (Rep. Exp. Res. Sta., Cheshunt, 1944). Preliminary trials by W. H. Read show that 5 per cent D.D.T. kaolin dusts or 0.02 per cent D.D.T. sprays give good control of tomato moth caterpillars (Polia oleracea). Red spider mites are not, however, controlled by this new insecticide, but D.D.T. can be added to petroleum emulsion sprays and the mixture used for the control of both pests. E. R. Speyer and W. J. Parr suggest measures for the control of tomato leaf-miners (Liriomyza spp.). These involve steaming the soil of propagating houses before introduction of the staging, and grow ing plants with a harder kind of growth than normal. Magnesium deficiency of tomato has been studied by O. Owen, who finds that spraying the foliage with 2 per cent Epsom salts, plus a wetting agent, gives good control. I. W. Selman finds that Cheshunt Early Giant lettuce is most resistant to mosaic virus when grown with low nitrogen and low phosphate, with medium watering. It is unlikely, according to P. H. Williams, that Verticillium wilt can be controlled by altering the pK of the soil, as the fungus can grow well between pH. 4.0 and 8.0. A severe loss of heliotrope cuttings, due to the fungus Corticium solani, is described by Mrs; E. Sheard. The report of the director (Dr. W. F. Bewley) shows that experi ments on the growth of tomatoes in gravel cultures have been commenced. Trials of bulky composts were inconclusive because of damage by enemy action.
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Cheshunt Research Station. Nature 158, 266 (1946). https://doi.org/10.1038/158266c0
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DOI: https://doi.org/10.1038/158266c0