THE TOMATO ROT.

Otago Witness, Issue 2813, 12 February 1908, Page 8

THE TOMATO ROT.

DISEASE APPEARS AT WAIMATE AND ASHBURTON.

From communications received from I Waimate and Ashburton there is e\ery | icason to believe that tomato rot has made its presence felt in both districts. The | first communication came from Waimate. A correspondent wrote: "I am sending you a specimen of my tomatoes, grown in | a glass-house. You will note that it has a brown scab on the upper part. I have grown tomatoes for several sears. and this is the first time this kind of thing has occurred. The tomatoes are said to be Ponderosa.*' The sample was submitted to Mr G. M. Thomson, F.L.S., who reported -as follows: — "The blight on the tomato is due to a fungoid or bacterial parasite, but 1 could not tell which without a detailed microscopic examination. If it only attacks the fruit it will be difficu't to deal with, as the application of any bactericide would probably damage the fruit or e\en make it unusable. I would recommend your correspondent to send specimens to the Agricultural Department. Mr A. C. Cockayne, the biologist to the department, has devotedespecial attention to bacteriology and the lower fungi in relation to plant life, and is probably the best authority in New Zealand on the subject."

Just after receiving Mr Thom-on's reply an Ashburton correspondent wiote forwarding a sample tomato taken from his garden and asking r or % information as to the nature of the disease from which they were suffering. The plants, he added, wore grown in a nlace sheltered from wind, and were all tied up to wires. This specimen we submitted to Messrs Xiramo and Blair, who. after consultation with well-known growers o? tomatoes, eamo to the conclusion that the disease was tomato rot, which is thuo described in a text book on the subject: —

"Rot (Maerosporium tomato. Cooke). — Description: This fungus generally attacks tho tomatoes when the> are over one half grown. The blossom end is attacked, the appearance of a small black spot being the first indication of the disease. This .spot increases in size until fully half of the toma.to is destroyed. The diseased part is black and sunken. ' and generally extends squarely across the tomato from side to side. The warm, moist weather of summer appears to be particularly favourable to the development of this parasite."

The best preventive of rot is a thorough spraying with Bordeaux mixture or other copper compound. In the case of our correspondents if" seems probable that their emu* are too far advanced and that the iii-ppse has made too much headway to be rhecAr-d. If such is the case every effort should be made to stamp oiit the disease b\ d"> s tro\insf the tomatoes affected. Where possible, q dry location should be selected for crowing- the plants and the stems should be kept free from the ground.

Where tomatoes are attacked by blight the leaves are first affocted. showing dark brown spots on the under side. The upper surface at the same time turns yellow, and the edges of the leaves turl downward, as a rule.

Two other diseases of the tomato are known, but they are probably caused by bacteria. No remdeies can as vet be named. It is probable that one of these organisms r= the first cause of the rotting' of tomatoes described.