Survival of Sea Beet and Sugar Beet inland in Suffolk

SURVIVAL OF SEA BEET AND SUGAR INLAND IN

G. D.

BEET

SUFFOLK

HEATHCOTE

E. M. Hyde's article on Cochlearia danica and other salt-loving plants extending their ränge due to salt being applied to main roads in Suffolk (Hyde, 1986) interested me greatly and reminded me of less successful colonization by such a plant. Sea Beet (Beta vulgaris L. ssp. maritima (L.) Arcangeli) is very frequent but restricted to the coast in Suffolk, growing on shingle banks and the sea defences, especially between the concrete blocks widely used to line the grassy banks along the marshes. Sea Beet will readily cross-pollinate with sugar beet, mangolds and red beet (Beta vulgaris L. ssp. vulgaris) although Simpson (1982) gives few records of these hybrids. Sea Beet and these hybrids vary greatly in form (e.g. in size and shape of leaf and in colour of the petioles) but their roots are generally long and much branched, enabling them to grow on unstable shingle banks.

Cultivated beets were produced from the wild type by plant breeders, and they retain many of the characteristics of Sea Beet, including susceptibility to disease. Well-established Sea Beet plants are almost invariably infected with one or more of the viruses which infect cultivated beet (i.e. beet yellows, beet mild yellowing and beet mosaic viruses) and often also carry fungal diseases such as mildews and leaf spots. Sea Beet has been closely studied by agricultural scientists as a possible source of disease for the farmers' crops but, perhaps surprisingly, there is little evidence to suggest that it is an important source of any of them (Gibbs, 1960).

One reason that Sea Beet is not a major source of disease for the sugar-beet root crop is linked to its tolerance of salt. Gibbs (1960) showed that the peach-potato aphid, Myzuspersicae (Sulz.), which is the aphid which most often carries virus from diseased to healthy beet plants, will not readily settle and feed on salt-sprayed plants. It is obvious to anyone Walking along a sea or estuary wall or bank that Sea Beet plants grow only on the water side where they are sometimes covered by salt spray, whereas many grasses and other plants which thrive on the other, inland, side are absent in this salty zone. This suggests that Sea Beet will not grow in competition with many other plants which do not like salt. J. W. Blencowe (unpublished) tried growing Sea Beet on a similar site except for the absence of salt spray. He chose a railway bank near Higham. The Sea Beet did not thrive and was overwhelmed by grasses in a few years. However, Sea Beet is always among the first plants to colonize estuarine banks, growing from the abundant, corky, water-carried seed this plant produces. It also grew for a while inland after the flooding in East Anglia in 1953, marking out the area covered by the sea water.

Commercial sugar beet is also tolerant of salt, and salt (sodium chloride) is often applied as a fertilizer, the recommended rate being 3 cwt./acre. Sugar beet can of course be grown inland, and the crop represents about 10% of the total acreage of crops and fallow land in the county, occupying about 59,000

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acres. However, unlike the Sea Beet, the sugar-beet crop is kept as free as possible from competing wild plants (i.e. 'weeds') as the yield of sugar from weed-infested crops is low.

Sugar-beet plants will grow for a while at the roadside when they fall from lorries, or near clamps or loading areas on farms, but I do not anticipate their becoming part of our flora. When the A45 road near Kentford was widened in 1979 some sugar beet was left unharvested at the side of the new road. This continued to grow for several years, especially on the bank by a new bridge (Nat. Grid. TL723 667), but it has nowcompletely disappeared and has been replaced mainly by coarse grasses.

I would like to know if any sugar beet has become established on the central reservation or sides of Suffolk roads where there has been much salt applied. It is true that farmers have a problem with 'weed beet' in some arable fields, i.e. sugar beet which grow from the long-lived seeds shed by sugar beet which have 'bolted' (producing seed in their first year of growth and not in the second as is normal), but that is another Stรถry.

References Gibbs, A. J. (1960). Studies on the importance of wild beet as a source of pathogens for the sugar-beet crop. Ann. appl. Biol., 48, 771.

Hyde, E. M. (1986). Maritime plants on Suffolk's roadsides. Trans. Suffolk Nat. Soc., 22,50.

Simpson, F. W. (1982). Simpson's Flora of Suffolk. Ipswich.

D r G . D. Heathcote

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