PRACTICAL GARDENING

Press, Volume CIX, Issue 32073, 22 August 1969, Page 6

PRACTICAL GARDENING

StmUb wrimt /«• ‘TH me to 1

M. LUSTY

Gardeners’ Queries

I have enclosed • small leaf from the base of my rubber tree. I wonder if you could identify the disease and whit I could do. If . any other leaves develop the same thing?— K.J. (North Canterbury).

I have been unable to ascertain the cause of the marking on the leaf. With the exception Of a few pests most problems of ficus can usually be traced to faulty culture. A light, draught-free position is best; watering should be minimal from late autumn through winter and given as much as required in the intervening period. Leaves should be kept free of dust deposits. Cou|d you please tell me the cause of the white, fluffy deposits on my hydrangeas? Is there something I should do about them? Can powdered sheep manure be used on all plants Or are there some that should be omitted? And is there a limit ‘to the amount that should be applied? “Amateur.”

Please note that name and address must be given even if you don't want them published. In future queries without names and addresses will be disregarded. The fluffy deposits are the egg sacs of the cottony cushion scale from which the next generation of stales, initially known as crawlers, will emerge. It is too late to apply winter oil now but superior oil or lime sulphur could be used effectively to exterminate them. Most Australian . and South African trees and shrubs, and a number of other plants, do not need supplementary feeding

—in fact some positively resent it. Greatest benefit from sheep manure is gained by adding it to the compost heap or applying it to vegetables or fruiting subjects.

1 have a young apple orchard with trees from two to four years old, trained as centre leader pyramids on M.M.104 stock. Last season I gave them three applications of urea 46 per cent at the rate of 2|!b per 100 gallons water (dilute saturated spraying) mixed with karathane, the only pesticide required to date. This appeared to give excellent results with more growth and greener leaves. The normal base dressing of fertiliser was also given. This season I would like to use foliar spraying more fully. Has foliar spraying been proved beneficial on apples? If so what fate per 100 gallons of water and frequency of application? Timing of first application, —are young leaves too tender? Can it be applied with any chemical, is liquid seaweed better than urea?— B.M. (Christchurch). Urea is the highest source of nitrogen available and as a foliar feed is very rapidly absorbed and utilised by the plant. There would be noticeable signs of its affect such as you mention but it can have adverse effects as well and must not be applied to trees in full bloom or late in the season. Leaf damage and delayed ripening are two side effects. Its use has been predominantly on apple crops but is now little used locally as far as is known, after having been used extensively a few years ago, although it still seems to hold advantages in the case of young trees. Unless there is a marked deficiency, the usual annual soil fertiliser treatments are considered satisfactory enough. The normal strength of urea application for mature trees can be reckoned on one ounce urea per gallon of water (5-61bs per 100 gallons) ahd your application would be about correct for young trees. It can be incorporate! in the usual spray programme and is compatible with all commonly used materials although some care is needed in combination with some such as lime sulphur and carbaryl. A compatibility chart will give details. Four to five applications of urea are normally given. Concerning liquid seaweed, several such plant foods are used but circumstances will dictate feasibility or otherwise of such inclusions. Unless there is a proved need for additives, there is no point in applying them just for the sake of applying them. Karathane requires care in its use with urea. Even though your trees may not be in full bearing there are other diseases and also pests which are bound to be present and which must be controlled by means other than karathane on a holding the size of yours. As a commercial grower, you should avail yourself of the services of the Department of Agriculture, Horticulture Division.

Nearly all the foliage on my vegetables turn yellow after a certain stage of growth has been reached, silver and red beet being most affected. The leaves turn yellow and crinkled and in the case of red beet the leaves also become dry and rusty. I get fair results with root crops but there is still yellowing of the leaves. I gave the whole garden formalin treatment but It does not seem to have had any affects. It also occurs in the strawberries. I am very disappointed as it is my only hobby.—“Fedup" (Rangiora). I do not understand why it should be necessary to regularly treat your whole garden with formalin. This is a soil drench used primarily in glasshouses to disinfect or sterilise the soil; it gives satisfactory control of soilborne fungus-diseases sUch as damping off and verticillium wilt, but does not control eelworms or weeds. The fumes can cause plant injury and for this reason it must be kept away from growing plants. The soil must be thoroughly aerated before it is used again after it has been treated with formalin. Formalin cad ’also be used for sterilising tools, seed boxes and glasshouse interiors. Your plants could be suffering from nitrogen starvation and it may be in your interests as vegetable growing Is a hobby of yours, to have a full , soil test made. It is, not possible to advise you further without seeing the area concerned.