TOMATO MILDEW

New Zealand Herald, Volume LXXI, Issue 21912, 22 September 1934, Page 8 (Supplement)

TOMATO MILDEW

SALICYLANI LI D E PASTE Some tomato diseases are easily checked; others can be eradicated only alter considerable expense and trouble, and there are a few for which a certain remedy has not yet hcen found Tomato mildew, known scientifically as Cladosporium fulvum, was until recently numbered among the latter. This fungus is easily recognised. The first signs noted are yellowish-red spots on the upper surface of the leaves, which, when turned over, reveal olivebuff, downy patches. As a rule, it shows first on plants in the middle of the house, but soon spreads, and eventually takes possession of e»cry leaf. By that time the spores aro fully developed, and a cloud of spores can be raised by a mere shaking of the plants. The exact cause of tomato mildew is not easily explained. It will appear in the best-regulated houses almost as frequently as in those in which carelessness is obvious. It is more prevalent in dull, warm seasons than in hot, dry ones, and is particularly liable to make an appearance in low-lying and sheltered districts. This does not alter tho fact that the disease has to fight harder for an existence in well-regulated houses than where conditions are left more to chance.

Considerable experimental work has been carried out in recent years with various spraying fluids for the control of mildews in general, on other plants as well as tomatoes, and considerable success has been achieved in the uso of salicylanilido paste, with tho addition'of a small quantity of sulphonated oil to increase its wetting and spreading powers. The following extract from die Gardener's Chronicle of January 21, 1933, is of interest: —

"In a matter of 24 hours after the first application the Bpore-bearing fungoid growth, visible on the under-sur-face of the loaves, was completely killed, being changed from a pale brown, fluffy mould to a mouse-brown, dried-up, powdery mass. After a week, however, a fresh outgrowth of spores was visible all round the margins of the numerous dried-up patches (sinGe apparently the vegetative portion of the fungus embedded in the leaf tissues had not been destroyed), thus showing the necessity of further spraying if the disease is to be prevented from recurring and spreading. This was immediately done, and repeated even a third time about 14 days later, with the result that all the subsequent top-growth tomato foliage grew away clean, .and thereby enabled the upper trusses of fruits to reach a decent marketable size and ripen on the plants. A second experiment, in which the strength used was half the quantity of the previous trial, had the desired effect of protecting all the sprayed foliage from primary infection and allowing the new growth to come away practically clean, whereas the control plants were badly mildewed. Further spraying of the new growth only was found to be necessary after an interval of approximately three weeks, and, as a final precaution, a fourth spraying was given after another two or three weeks' interval." STRAWBERRY CULTURE SEASONAL ATTENTION It is now time to do everything possible to help the strawberry plants and prepare for the fruiting reason. The beds should first be thoroughly cleared of weeds. Any such work will be impossible, when the litter has been put on,, so the surface soil must be thoroughly hoed to break it down to a j fine tilth.

The question of feeding will Ijnve to bo taken into consideration. The plants use up a good deal of energy while carrying a crop, and a stimulant applied now will assist in carrying them over the critical period of flowering and fruiting. If the bed has not had a dressing Qf a complete manure, an application should be given which will supply all tho three essentials—nitrogen, phosphate and potash. X mixture of loz. of sulphate of ammonia, 2oz. of sulphate of potnsh, and 3oz. of superphosphate will do this, and can bo sprinkled close to the plants in showery weather, using a handful to one yard run of row. The fertiliser should bo applied on both sides of the row. In the case of beds which are comparatively clean of weeds it may be as well to reverse the usual operations, giving the fertiliser first, so that it may be worked into the soil during the hoeing. Strawberries arc subject to the attacks of so many fungoid diseases that spraying should not be neglected. It is best to commence spraying one month after planting, and repeat every 14 to 21 days until the berries begin to colour, omitting the period when the beds are in full flower, when damage may inadvertently bo done to the blossom. The mixture used is 61h. of bluestone, 91 h. of washing soda, and 50 gallons of water. This is known as Burgundy mixture. CURIOUS MEXICAN PLANT The curious plant, Monstera deliciosa, is frequently seen growing in gardens round Auckland. It is really a climber in its native habitats of Mexico and Costa Rica, the woody branches clinging to other trees by means of long cord-like aerial roots developed along the length of the stems. The leathery deeply divided leaves aro perforated with large holes The flowers which are seldom seen out of doors in this country are in the form of n spathe like the arum lily, yellow in colour. They produce a cylindrical pineapple-like fruit which is edible, the flavour resembling that of both the pineapple and banana. During the summer, they require plenty of water to keep them in vigorous growth and shade only during the hottest part of tho day.