FLOWER GARDEN FOR FOES

Timaru Herald, Volume CXLIII, Issue 20930, 8 January 1938, Page 16

FLOWER GARDEN FOR FOES

SUMMER SPRAYING The proverb which reminds us that “It is no use locking the stable door after the horse has bolted” may well be applied to the treatment of plants in the flower garden during the summer months. When the weather is warm and mild, plant foes flourish, and many of them are capable of increasing at such a rate that it is of little use taking precautionary measures once they are firmly established on their hosts. A good example of this is found in the common greenfly. At the outset this übiquitous pest is not very difficult to control, for it attacks the tender young tips of new growth where It is readily killed by means of suitable sprays. But once allow these aphides to multiply sufficiently for some of their number to be driven on to the older foliage, and they immediately protect themselves by curling the leaves around them, so that it is well-nigh impossible to get a spray into contact with their bodies. Similarly, with many diseases caused by fungal infection, once the fungas has grown well into the tissues of the leaf or stem, it is of very little use to apply even the most efficient fungicides. The all-important thing is to get the foliage covered with a suitable spray before the damage is done, so that any spores carried through the air from a nearby infected garden is killed as soon as it attempts to grow on the protected plant. A Simple Method of Grouping

It is not necessary to be a chemist or a learned plant pathologist in order to carry out a perfectly successful campaign against the common pests and diseases met with in English gardens

during an average summer. Though the number of foes which may attack one's plants is certainly numerous, these invaders can most fortunately be grouped—at any rate so far as treatment is concerned—under three or four main headings, and within these groups remedial measures that prove effective against one are equally satisfactory against another. First of all, it is necesary to distinguish between what are rather loosely termed “pests” and “diseases.” By the former term is usually meant some insect or caterpillar that lives on plants, whereas a “disease” is caused by a fungus, or, in some cases, a virus. The last-named are for the most part extremely difficult to control, and, though a great deal of research work is being carried on at various stations as to their nature and cure, as yet there is not much of a positive nature to record. Consequently, they will not be referred to further in these necessarily somewhat abbreviated notes. Countering Disease Diseases of fungal origin do not present the same difficulties, of most fungi are killed if brought into contact with sulphur or a copper salt Bordeaux mixture is a highly satisfactory fungicide, which can be used with safety on most plants, and is effective against mildews, coral spot disease, cluster cups, and many more of the fungi which commonly attack garden plants It Is prepared by carefully blending lime and copper sulphate, so that the acidity of the latter is just neutralised by the alkalinity of the former. It can be purchased ready mixed by skilled chemists, and only requires to be dissolved in water at the strength recommended by the manufacturers. With all these proprietary fungicides It is only necessary to follow printed instructions on the packet or container as to mixing, and then to apply them to the plants in the form of a fine but driving mist, and in such a way that not only the upper and lower surfaces of the leaves are covered, but also the stems. It is particularly necessary to

treat roses, antirrhinums, hollyhocks, violas, and chrysanthemums in this way, as these are the plants most likely to be attacked by disease of fungal origin. A first application may be given now, and this should be repeated after a week or so, for the very obvious, though sometimes overlooked, reason that by that time the plants will have made further growth, which will, of course, not have been protected by the first application of fungicide. Sometimes it is even advisable to give a third dose later on in the season, but this will depend to some extent on the prevalence of disease in neighbouring gardens or allotments, and also on the weather. If the summer is very mild and wet, spraying must be continued longer than would be the case in a dry or cold season.

Biting and Sucking Pests

For the purpose of devising counter measures, pests can be very conveniently divided into two types—those that attack plants by sucking their sap and those that feed by biting holes in the leaves or stems. Greenfly, red spider, thrips, and frog flies belong to the former class, while caterpillars, slug worms, and weevils come under the second heading. The distinction is an important one, as the line of treatment is quite different for each class. Should the novice be in any doubt as to what type of pest is attacking his plants, he should examine the damage closely. If there are pieces eaten right out of the stem and leaves, he may be certain that a biting pest of some sort is at work, but should there be no sign of actual holes, and only more or less blotchy discolouring—either silvery or yellow—or, alternatively, if the leaves are badly cockled or curled, he can be fairly sure that a sucking pest is responsible. Insects t’jat feed by biting the leaves are poisoned by spraying the foliage in good time with some powerful chemical. Fortunately, substances that are

poisonous to insects are by no means always harmful to human beings and

domestic animals as well, and, consequently, the gardener can choose insecticides that the horticultural sundriesman describes as non-poisonous (that is, not poisonous to human beings), if there is any danger of the spray falling on nearby edible crops, or of doing harm to children or pets. Sucking insects obviously cannot be dealt with in the same way, as they do not eat the leaves, and, therefore, cannot be poisoned so simply. Nevertheless, two satisfactory methods of attack are open to the gardener. One is to paralyse the insects by bringing a nicotine solution into contact with their bodies, while the other consists in filling up their breathing pores with soft soap or petroleum emulsion. Nicotine is very powerful in effect, and must be used with a certain amount of precaution, as it is poisonous to human beings. However, its toxic effect passes off very rapidly, and when exposed to the atmosphere the principal necessity is to keep the bottle of concentrated fluid well out of reach of irresponsible persons. Petroleum emulsion washes, of which there are now several on the market have been immensely improved, due to more scientific methods of manufacture, and are thoroughly reliable. As they are non-poisonous, they may be employed without special care. How to Apply Sprays It should be noted particularly that there is a slight difference in the method of application of insecticides according to whether they are used against one class of pests or the other. In attacking biting insects, the object is to cover the foliage thoroughly with the finest possible film of poison, and the spray is applied in the form of a very fine mist. In the case of sucking insects, it is, as already mentioned, absolutely essential to get the insecticide right into contact with the bodies of the invaders, and for this purpose a rather heavier, more wetting spray is desirable. Incidentally, fungicides require to be applied in mist-like form,

in the same manner as anti-biting insect sprays. Most types of modern spraying apparatus are supplied with at least two different nozzles, giving sprays of varying coarseness, and the gardner should make use of these accordingly. Moreover, it is important to wok the machine at the right pressure. DAHLIAS FOR EXHIBITION The first essential is to see that plants are growing steadily and are free from pests. This can be maintained by frequent sprayings with such solutions as Clensel, arsenate of lead, nicotine solution, white oil, etc. Every grower will have his own particular fancy. The next step is that first cutting back. This is achieved in two ways, and is done when the plant is 18 inches to two feet high. The first way is to nip out the growing centre of the plant only. The second is to cut the plant back to either four, six, or eight laterals. This is effected by making a clean cut across the main stem or trunk of the plant The number of laterals a plant will produce is ascertained by the number of leaf branches left ’on the plant. The best number for most varieties is six, although there arc some that will carry up to 10 and 12 laterals, and produce show blooms on every one. This method is particularly suited for giant decs., but for hybrid or garden cactus varieties I would recommend nipping out the centre of the plant only, and encouraging a strong lateral growth. After the plant has been cut back, it is advisable to give it a light feed of bone and potash, four parts bone to one part potash. This mixture will give the plant the necessary stimulus to start the lateral growth and at the same time will have no injurious effect on the plant. The mixture is sprinkled lightly round the plant (using one ounce to the square yard), and then watered in. As the laterals develop the plant will need more water, and should be watered at least twice a week. This is, of course, dependent on the weather conditions and type of soil. When the laterals begin to develop the plants should be mulched with either cow or stable manure—cow manure for light soils and stable for heavy soils. This mulch not only conserves the moisture in the soil, but gives the plants that little extra that makes all the difference to their growth.

The next step in the growth of the plant is the bud stage Where a plant is grown to six laterals, six groups of buds will appear simultaneously on mast varieties. Now, should the grower allow each of the six terminal buds to develop, he will certainly have six good blooms out at practically the one time, with the consequent loss of size, and this in most instances constitutes that particular plants crop of exhibition blooms for the season. To counteract this a further cutting back is necessary.

The best way is to pick the most likely looking lateral and select the bud required, either crown or side bud, according to vigour of plant. In giant decoratives that are inclined to be a little bit coarse, it is advisable to select a side bud and remove crown and other side bud. This gives the bloom much greater refinement. Having selected the first flowers as specified, cut back the next two laterals to the second leaf junction, then the next three, to the third and fourth junctions, counting down from the top in each instance. This will ensure a consecutive crop of exhibition blooms throughout the season without any serious lack of size. This method, although it entails a good deal more work for the grower, will amply repay him for his time and trouble, and the blooms produced will be all up to exhibition standard, the obvious reason being that at no stage will there be more than two blooms maturing at the one time, enabling them to derive the full nourishment

from the plant. Regarding the method of nipping out the centre, the procedure is practically the same, the only difference being that the laterals not wanted are taken away from the plant altogether, leaving just sufficient to make a well-balanced plant.