Queries from gardeners

Press, Volume CXVI, Issue 34100, 12 March 1976, Page 16

Queries from gardeners

Enclosed some leaves from my rubber plant. Could you please say what is the matter and how I can overcome it? I feed it every three weeks with zest and water It well at the same time. — Mrs O. (Opawa). It is essential not to regulate watering on a time basis but to appiy it according to a particular plant’s needs. The feeding of plants can be overdone and can have adverse effects, particularly when a plant is under stress of some kind. The problem above suggests a physiological condition induced probably by the combination of factors mentioned in the query and outlined above.

These beans of mine have begun to look a bit siekish to me after making good progress. They haven't been sprayed or given anything and it looks like more than half the crop has got "it/* — K.M. (Christchurch).

The bacterial disease of halo blight was diagnosed as the prevailing trouble on your beans. This disease can be carried over to a succeeding crop through infected self-sown seedlings. At this stage of infection all badly infected plants should be pulled up promptly. Remaining plants should be sprayed with copper oxychloride. Rotation is also advocated.

Strangers of a broad leaf nature were planted out in the flower garden after they appeared with celerv seedlings. They are still growing and the broad leaves are over 12 inches long. Could it be tobacco? —B.W. (Christchurch) It is regretted but letters are impossible to answ-er without a specimen. Have the tomatoes enclosed a disease, or is the fault caused by weather conditions? It begins with a small slit, and then enlarges. — "Enquirer" (Christchurch). The form of disfigurement dis-

played on these tomatoes Is known as fruit-splitting. This is a physiological upset, the cause of which is not known. As far as can be ascertained only two varieties, Potentate and Carter’s Sunrise, are particularly susceptible to it. This problem is distinct from two other ones, namely growths cracks and catface.

I am enclosing a specimen of chrysanthemum which has had for the last two years peculiar green nodes on the stems. Thinking it was scale I sprayed with white oil but to no avail. Can you suggest something to save it? — E.W. (Christchurch).

Chrysanthemum gall mite (or midge) is responsible for the protrusions on your plants. These pests can cause considerable distortion of the leaves and stems of chrysanthemums and are not uncommon where these plants are grown. White oil is completely ineffective against them. Of the materials available for home garden use, diazinon may provide the best control.

I would be grateful for identification of this weed, it first made its appearance in an established vegetable garden and in spite of control by weeding it has spread even to the flower garden. Worst of all, it is very thick, almost mat-Hke, in the asparagus bed. —"E.S.S." (Blenheim).

Weeds can encroach, establish themselves in many ways, and are often spread unwittingly by cultivation, the use of contaminated compost or the introduction of some form of organic matter. Certain areas sometimes provide ideal conditions for the establishment of such unwanted growths and it becomes a constant battle to keep good control over it. Foxtail is the invasive grass in this case, and while its small rhizomatous roots never attain the hold in the soil that

does twitch, It does spread a bit. Where plants are isolated it is probably most expedient to grub them out. Large areas of it, such as in the asparagus bed, can be sprayed with dalapon.

Can you please tell me If the enclosed Is the edible kind of angelisa that can be candied and preserved? Also my Meyer lemon Is about five years old and has never borne any fruit. If flowers and when the fruit forms it falls off. Why? E.B. (Ashburton). It was not possible to identify the species from the small sample, many of which can be utilised in the way mentioned, though some are very much more preferable than others. The reason why the lemon will not bear fruit is not easy to determine without either seeing the plant or having more details about its position, etc. There could be many factors involved such as too cold and/or draughty a position. Dryness, insect attack

and the lack ef ene er more minerals in the soil, are others. A grapevine bears good sound fruit but has a bitter taste in the ripe fruit. Is there anything I can use to sweeten them. What nutriment could I use in the soil. Also what do you suggest for the soil before planting onions or putting In the seed.—E.J. (Rangiora). Onions respond to near alkaline soils and the addition of lime well in advance of sowing or planting is recommended where this has not been carried out in the past two-three years, and particularly so if acidic fertilisers such as ammonium sulphate have been much used. Blood and bone is quite suitable. Bitterness in the fruit may be due to a soil problem associated with the roots growing into cold sub soil or too wet conditions. However, this is one of those problems where examination of the plant is likely to •provide more possibilities for the cause than any conjecture.