THE SPREAD OF BEET YELLOWS AND BEET MOSAIC VIRUSES IN THE SUGAR-BEET ROOT CROP I. FIELD OBSERVATIONS ON THE VIRUS DISEASES OF SUGAR BEET AND THEIR VECTORS MYZUS PERSICAE SULZ. AND APHIS FABAE KOCH

A survey of aphids and virus diseases of sugar-beet root crops in eastern England was made between 1940 and 1948. Prior to 1943 the observations were made on fertilizer experiments; from 1943 onwards they were made on commercial fields selected for position in relation to beet and mangold seed crops. The incidence of beet yellows increased with increasing numbers of Myzus persicae , but not of Aphis fabae. The relation with M. persicae was sufficiently close to suggest that it is the most important, possibly the only important, vector of beet yellows virus. Beet mosaic virus also increased with increasing numbers of M. persicae , but the relation was not close enough to exclude the possibility of other vectors.
Numbers of A. fabae on sugar beet were slightly, but consistently, depressed by the use of salt as a fertilizer. Other fertilizers had variable effects. Neither aphids nor virus are likely to be greatly affected by fertilizers.
Beet yellows is most prevalent in areas where seed crops are grown, but within these areas nearness to individual seed crops did not appear to increase its incidence. M. persicae were more numerous on sugar beet in seed-crop areas than elsewhere, and this alone might account for the prevalence of yellows. Beet mosaic virus is more closely associated with seed crops than is beet yellows. It is most prevalent near to seed crops within the seed-crop areas.     

稀土元素对甜菜种子萌发,幼苗生长及块根产量的影响

本文研究了稀土元素对甜菜的生物效应。结果表明,稀土元素可显著地提高种子萌发率,促进幼苗生长,增加幼苗根系活力、叶片净光合速率与块根产量,并明显地降低了甜菜叶片细胞膜在低温下的透性,即提高了叶片的抗寒力。     

SEED AND SOIL TREATMENT WITH SYSTEMIC INSECTICIDES TO PREVENT APHID COLONIZATION OF EMERGING BEET SEEDLINGS

Dimefox at 2 lb. or diethyl ethylthiomethyl dithiophosphate (Thimet) at 1 lb. applied at drilling in 100 gal. water along the drills, or seed treated at rates giving 6–8 oz. Thimet or 8–24 oz. diethyl ethylthioethyl dithiophosphate (Disyston) per acre†, made sugar beet seedlings toxic to aphids up to 30 days after sowing four root crops in April-May, and up to 30–40 days after sowing five steckling crops in autumn. Malathion, demeton, demeton methyl, bis (dimethylamino) azido phosphine oxide (N.C.7) and schradan were less effective. The infestation of green aphids was decreased by the treatments during what is often a critical period for virus infection in summer-sown stecklings and occasionally in spring-sown root crops. Germination was 73–100% of the control after soil treatments, 91–98% after Disyston seed treatments and 62–84% after Thimet seed treatments. The treatments slightly decreased Aphis fabae injury to steckling seedlings in 1955 and the number of plants with yellows in a steckling experiment in 1956.