ANSWERS TO INQUIRIES.

New Zealand Journal of Agriculture, Volume 54, Issue 4, 20 April 1937, Page 254

ANSWERS TO INQUIRIES.

IN order to ensure reply to questions, correspondents must give their name .and address, not necessarily for publication, but as a guarantee of good faith. Letters should be addressed to the Editor. WILT. IN TOMATOES, VERBENA, AND LARKSPUR. C. T. 8., Timaru : Has the growing of blue lupin caused verticillium wilt in my ■ tomatoes this season ? Last year I sowed blue lupins in February for green manure ; they grew to about 12 in. and then were dug in for green manure, on the same ground. Verbena and larkspur were planted, and long before maturity fully 50 per cent, of the plants withered and . died. Tomatoes were similarly affected where planted in the same ground. Only one survived. The Horticulture Division : There is no record or proof of blue lupin being a host of V. albo-atrum. The practice of planting the types ■of plants mentioned by you on top of recently dug-in sappy lupin is to be condemned, as all the conditions are suitable for fungous attack. Without specimens of affected plants it is impossible to determine the cause of the “ wilt ” condition, which in your case is probably Sclerotinia, but not necessarily the same organism attacking both the larkspurs, &c., and the tomatoes. ■ ACTION OF BLUESTONE SOLUTION AS DRENCH. J. B. V., Te Mata . I understand that when drenching sheep with bluestone or a combination with bluestone, the bluestone closes up a certain canal or passage and thus allows the solution to go straight to the fourth stomach. If so, how long a time elapses after the first part of the dose (say, J oz.) enters the. mouth before that passage is affected and closed. The Live-stock Division : It has been found by Dr. Clunies Ross in Sydney that the action of the bluestone solution commences in the mouth of the animal. It is the chemical reflex action of the copper on the mucous membrane of the mouth which causes the closure of the oesophageal groove. Therefore, any fluid swallowed by the animal should all go into the fourth stomach. Dr. Ross's experiments show that this is the case. It is also possible first of all to give a bluestone solution alone and then follow up within fifteen seconds with a dose of any other medicine which you wish to reach the fourth stomach directly. WIREWORMS IN POTATOES. Subscriber, Totara Flat : Is there any remedy for the control of wireworms in potatoes, and are certain varieties more susceptible to their ravages than others? . The Fields Division Beyond thorough cultivation, there is no satisfactory means of dealing with wireworms. Practically all pasture carries a population of wireworms, and when the. pasture is broken up and the land sown in such crops as potatoes the wireworms may attack and do considerable damage to the tubers in the first season, but infestation diminishes considerably the longer the land is under cultivation. Soil fumigation may at times do a little good, and the use of calcium cyanide worked into the ground during cultivation, at the rate of 200 lb. to the acre, has been said to have a good effect. The cyanide should be applied not later than fourteen days before a crop is sown. This treatment is only practicable, however, for comparatively small areas. It is not considered that certain varieties of potatoes are more susceptible than others to the ravages of this pest.