Gardeners’ queries

Press, 15 June 1979, Page 7

Gardeners’ queries

We have recently discovered that our Brassicas have developed club root and understand that we must use some kind of soil fumigant to eradicate it. Basamid was recommended as suitable, but we wonder if this should be used in a small garden, especially as we have many other vegetables growing well end do not want to use a fumigant which could harm them. We understand that lime should be sown to help the soil but would appreciate if you could give us advice ■bout this. This is the first time that club root has been found in our vegetable garden. —P.S. (Chch). Club root is a fungus disease which effects only Cruciferae which includes all members of the Brassica family and such weeds as Shepherd’s Purse and ornamentals like Alyssum; it can be spread by means of infected seedlings, cultivation and surface drainage water. This disease has a long viability in the soil and favours acidic mediums; the addition of lime can therefore be helpful in controlling it. Soil sterilants can be used tn control, but because of the difficulty of preventing movement through the soil following application, it should be restricted to areas which have

nothing growing in them. Suggested treatment Is to make up a dilution of benlate — lOg to 101 o£ water — and apply 200 ml of this solution per plant to the soil directly where each one is planted. Hydrated lime is the quickest acting form of lime to raise the pH o£ the soil and should be applied at least six weeks before planting or sowing o£ any Brassica crop. A soil acidity test is helpful in determining the amount of lime which should be added. Would you please explain the hot-water treatment for Chrysanthemums and why.— —V.B. (Chch). The hot water treatment of Chrysanthemum stools — which implies the basal portion with roots attached — may be carried out where eelwonn is either present or is suspected to be present in the plant. The procedure is to submerge the stool in water maintained at a consisten 46deg Celcius for exactly five minutes. The stools must be free of soil before treatment and cooled with cold running water immediately afterwards. This year I wish to graft my own standard roses as I have some varieties which have done verv well for me. Is September the best time to do this and how long must the cuttings be as I am going

to use my pruning! from this winter for this purpose?— "Standard" (Chch). Standard roses are generally obtained by budding, not grafting, in the generally accepted sense of the term. The wood for this purpose can come from the desired variety, whether bush or standard. A cutting from a standard rose will not produce a standard on its own — it must be budded on to a long stock which is about one metre high. The cutting, which is to act as the root stock and standard part of the operation, should be selected from the strongest, hardened past season’s growth (commercial growers generally select from rosa multiflora). The cutting should have all but the top three or four buds removed before planting. This may be at any time during the winter. The plant should be staked for support. Budding is carried out In late January and early February at a point just above the new growth close to the old wood. In winter all the growth arising above the union between stock and scion (the desired variety which was budded in mid-summnerl and anything which has developed below this point must be rubbed out. Budding Is necessary only where the root stock is other than the desired variety.