Gardeners’ lqueries

Press, 4 March 1983, Page 15

Gardeners’ lqueries

GARDENING

by

M.Lusty

Please tell me whether acephate has been approved yet for use on fruit trees? If it has, would it be more effective than carbaryl; would it have carbaryl’s thinning effect if used too early, and what would the waiting time be after application? G.B. (Chch). Acephate has been approved for use on fruit. It has a systemic property and is more residual than carbaryl as well as being of broader spectrum. The waiting period is seven days and it does not have a thinning effect on fruit.

I am enclosing leaves off my chrysanthemums and would be grateful if you could advise what they should be sprayed with to overcome the disease. The trouble starts on the bottom leaves and by the time we are into April and May there will be very’ few leaves left which are unaffected. The plants get regular. doses of home made liquid manure and Lush watered on to them occasionally. “Edna” (Westland). Unfortunately, I hdve been away recently and so have not been able to attend to queries. Where samples were included these have deteriorated beyond the possibility of diagnosis. The problem as you have related it does not sound familiar to me so I am unable to be of direct assistance. It is generally advisable to stop feeding these plants once the buds show the first signs of colour. If you would care to forward a further sample, it should be possible to be of help. Could you identify the disease which is affecting my glasshouse tomatoes? This is the first season that I have used a glasshouse and I thought that I had done everything right — sterilising the soil, spraying for both virus and insect pests, but this problem has arisen. What precautions should be taken to avoid a repetition? Also, my silver beet is suffering from considerable yellowing of the leaves. Is this because of soil deficiency, inadequate watering, or disease? G.W. (Chch). Again, the specific nature of this problem regrettably cannot be given for the reason stated in the previous reply. The management of glasshouse crops, particularly tomatoes, reouires constant attention to cultural matters during the growing season and is not quite the plain sailing that is often

imagined. Watering and air circulation by which means humidity is controlled, are vital aspects of tomato culture. Opening of vents and/or door(s) during the day, together with clamping down at least once during days of high temperature and bright sun, is particularly beneficial. Attention to soil moisture requirements

should be maintained on a constant basis and spraying for pests, such as white fly. and diseases, attended to with the minimum of delay. The trouble with the silver beet may be due to aging of the leaves but could possibly be due to the need for more nitrogen availabiliity. Lack of sufficient moisture can have an affect on mineral uptake from the soil and can also show itself through some yellowing and flaccid nature of the leaves.

I seek your advice bn choice of a suitable shrub to soften the somewhat stark, street-facing exterior wall of my house (see enclosed photo). I would like something which is showy, fragrant, requires little maintenance, is not a “magnet” for bugs and pests, and keeps its looks in winter especially. I realise my criteria conflict, but hope you can at least make some suggestions. K.B. (Chch). One thought which came immediately to mind was to put up a trellis and grow a climber on it this would leave the ground in front free to plant a shrub or two.. Climbing plants which could be considered include passion fruit, bougainvillea. hardenbergia. .jasminum and mandevilla. For tall-growing, individual, background planting suggestions include species of banksia, nerium, callistemon, grevillea, protea. and lecadendron.

Could you advise on a suitable spray to eradicate a large japopiea bush which is growing merrily with an agapanthus? I wish both to be eradicated.

Trying to dig them out is a Herculean task and beyond my strength, so I presume a spray is my only solution. Shoots from this bush are appearing all over my lawn and so my despondency grows. Only grass and concrete steps surround this four foot square of unsightly japonica and agapanthus. H.W. (Chch). There is not a great range of herbicides available to the home gardener’ for killing woody plants. A combination of 2.4.5,-T and 2,4 D would probably be the best recommendation. even if you have to make up the mixture yourself. Application needs to be over all and must be applied with great care on a still day as you are handling hormones which can be very damaging to other plants. Glyphosate should take care of the agapanthus.

I would appreciate your advice on over-wintering bedding begonias. I have been told that it is satisfactory to leave them in the ground and cover them with straw. I have also read that it can be reasonably successful to lift them and store them in sand for the winter. P.W. (Chch). Where reasonably good conditions prevail, such as good drainage and not too cold over the winter, then preference is to leave begonias of this type where they are. A ‘clean up' and feeding wiith a general fertiliser just before the recommencement of growth will set them off to a good start. Where lifting is required, or desirable, the plants should be laid out in a friable medium in a sheltered position and then replanted in early spring.