Gardener’s queries

Press, 13 December 1985, Page 14

Gardener’s queries

Could you please advise whether the top can be trimmed off a Casuarina cunninghamiana without any harmful results to the tree? Also, if topping is possible, when would be the best time to do it? E. H. (Nelson). There should be no problems associated with the topping of Casuarina cunninghamiana, a task which is perhaps best done in spring time. Where it is intended to restrict the height of trees it is generally in the best interest of all concerned not to wait until they are far beyond this objective before carrying out the job. Attached is a specimen of a tomato plant from our glasshouse. Each year, with every variety, this curling of the leaves occurs when the plants are about four to five weeks old. The soil is always sterilised with basamid. Fertiliser is well supplied and insects and disease are regularly sprayed against. Your comments would be appreciated. J. H. (Chch). The use of chemical soil

sterilants makes it vital to the health of the subsequent crop that the soil is fully aerated before any sowing or planting is carried out. This requires more than just forking over the top' few centimetres but going at least 200 mm deep. The problem that has arisen in this case illustrates the point well, for the noticeable affect on the plants has only occurred after the plants have become well established and the roots have penetrated the lower regions of the soil. As well, there were indications of the onset of leaf mould, a common complaint. of indoor tomato crops, the control for which is dichlone, benomyl or zineb. Please find enclosed leaves from our raspberry canes which are badly infected as per samples. Could you tell me wbat it is and bow to eradicate it? I. L. (Chch). The leaves have been badly infected by rust, a fungal disease which can become both very persistent once it has become well established and