FIGHTING THE CALIFORNIAN THISTLE.

Otago Witness, Issue 2883, 23 June 1909, Page 8

FIGHTING THE CALIFORNIAN THISTLE.

Professor H. L. Bolley, of North Dakota, has for several years past been endeavouring to ascertain the effects of certain wellknown compoimds upon plant life. fla claims that he has met with success in treating even such a tenacious grower as the Cknada thistle. In New Zealand this pest is commonly termed the Californlan thistle. The plants are identical. According to a report just received, '"come of the larger farmers are spraying thousands of acres for the destruction of mustard" mi their wheat crops. Where the weeds have been holding full sway the increase in- oroij is phenomenal. Farmers have reported ashigh as five bushels of wheat per acre increase, besides ridding the land! of the* weeds." It is evident from. the report (says a. writer in the _A_iistrala9ifi.n) tha/t th& most effectivo work has been done, in killing mustard and the Canada thistle. Professor Bolley gives the following- list of weeds which, he states, may be controlled bychemical sprays: False flax, wormseecß mustard, tumbling mustard 1 , common wild ball mustard, corn cookie, cbickweed, dandelion, Canada thistle, bindweed, plantain, rough pigweed, kinghead, ' Red River weed, ragweed, and cooklebin. Many of these weeds ana known to us in, Australasia by the same names, and probably others > occur here under different names. As a general rule, weeds do not seriously interfere with the growth of a cereal crop. .Much, -however, depends upon the season. The sue-, cess claimed by Professor Bolley suggests that similar work might advantageously be carried out by the different agricultural

departments nf Australasia. The effect of a number «f substances Jhas been investigated. Common salt, sulphate of iron, and'-arsenite of soda, have given the best results. The most popular is iron sulphate. A summary of the work was recently published "by the Rural New "Sorker, and it was mentioned that in spraying for mustard a sohition is made by dissolxring feom 751b to 1001b of toe iron sulphate in 52ga! of water, and this makes afoout the amount to Tjse on an acre. The spraying is done with any kind of a sprayer that -will cover the land at the tim© -when tibe amistard plants are just "beginning to show the first bloom. - A bright, still day is best. When salt is used, one-third of a barrel is dissolved in 52gal of water. For tihe came amount of water, ljlb of sodium aisenite is used. For ragweed, tbe salt and iron sulphate give best results, -while for Oagada thistle the arsenic is most effective, -with salt next. The arsenio is a deadly poison, and great ■3are should "be taken in -using it. When trying to kill the Canada thistle in pastures it will "be safer to use sbrons solutions of common salt.. Professor Boiley states that the spraying defoliates the thistle if applied in the/"- soring, and prevents the production of seed.- It can €aen/be cut off by the binder, and iust about the- time it 19 asain able to retaliate it 'receives further smothering if in a paddock intended ior cultivation by the autumn ploughing. If in a" permanent pasture a fecond spraying would be necessary. ' ,