506 



The Weekly Florists' Keview« 



MARCH 29, 1900. 



live in the memory of his loving 

 friends. They are safe in a community 

 which gave him esteem and confidence 

 because he had honesty, conscience, 



DISEASES OF THE ROSE. 



Bv Pkuk. Uvkon D. Halsiuli. 



[Read before the Americap Rose Society at New 

 York.] 



The earliest trouble of the rose to 

 engage my attention ten years ago, 

 when I first went to the New Jersey 

 Experiment Station, was that due to 

 nematodes. In the report of that year 

 it is recorded that "sickly stunted 

 greenhouse roses have been sent to 

 the station and the cause for the lack 

 of vigor was not far to seek. The 

 roots of the plants were badly knot- 

 ted and the whole root system infested 

 with gall-worms." 



In the report for the next year (1891) 

 the following is found recorded: "Com- 

 plaints have come to the station from 

 various quarters of a shortness in the 

 hot-house rose crop, and a visit made 

 to Madison and other rose-growing lo- 

 calities convinces me that the trouble 

 is not due to any one enemy. The af- 

 fected rose plants have a stunted, sick- 

 ly appearance; they fail to send up 

 strong shoots, and only develop short 

 stems, bearing pale, sickly leaves. 

 Such plants fail to produce good flow- 

 ers and are comparatively worthless. 



"The roots of such specimens may be 

 swollen in places and the knots con- 

 tain multitudes of nematode worms. 

 It is of great importance to have the 

 soil used for potting plants or the 

 greenhouse bed free from worms, and 

 of course only plants with roots free 

 from knots and galls should be used. 

 The greatest trouble with the rose 

 plant soil is probably the manure that 

 is used in great abimdance by the 

 growers. It is likely that this manure 

 is infested with the worms. An ex- 

 periment in raising roses in a soil 

 where stable manure is replaced by a 

 judicious mixture of commercial fer- 

 tilizers, is well worth trying. It has 

 been shown, for example, during the 

 present season, that sweet potatoes 



principle. He was the first president of 

 the Gardeners' Club, as he deserved to 

 be by his position in the trade and 

 his enthusiasm for the organization, 

 and it owed much to him, he having 

 kept it up when others might have 

 failed. But its origin was literally as 

 stated in the Review. It is a matter 

 always known and of record. RIX. 

 Baltimore. 



can be grown to great profit without 

 the city manure that has been the 

 standard source of plant-food among 

 truck farmers. Also it has been dem- 

 onstrated that potatoes thus grown are 

 less liable to attack of the various rots 

 and decays. If the right mechanical 

 consistency for the roses can be ob- 

 tained in connection with the commer- 

 cial fertilizers, it is quite evident that 

 the soil would be under better con- 

 trol and less liable to various infec- 

 tions." . 



In 1S92 six pages were given to ne- 

 matodes, thus showing that the study 

 of the subject had been continued. The 

 last words by the speaker upon the 

 subject are in an article written by 

 request for the Florists' Exchange, 

 and published in its issue for .Janu- 

 ary 27th of the present year. From 

 that article the closing paragraphs are 

 quoted: "The point that most inter- 

 ests rose growers is how to get rid 

 of the nematodes. In order to do this 

 it will be of much assistance to kuow 

 where the worms come from — how 

 they propagate and get into the roots 

 of infested plants. These eel worms 

 are much more abundant than gen- 

 erally supposed, and it is only when 

 they are numerous that their mischicl: 

 becomes apparent. In looking up the 

 subject of tomato blight in the south 

 some years ago, it was observed thai 

 the tomato plants were, almost with- 

 out exception, more or less affected 

 with root galls, and the same is true 

 of a large list of plants, both herbace- 

 ous and woody. The nematodes are, 

 as a rule, m.uch more abundant in 

 warm climates than elsewhere, and 

 the lack of these pests in northern 

 gardens is likely due to the freezing of 

 the soil. 



"The greenhouse furnishes the 

 proper condition for the propagation ot 

 the eel worms, and this naturally 

 raises the question of how they first 

 get into the bed. This may be in one or 

 more ot several ways. They may be 

 already in the roots of plants, but in 

 small numbers, when the plants are 

 placed in the house. To guard against 

 this, the roots should be examined as 

 closely as possible for the galls, when 



the beds are set, and all galled rose 

 plants excluded. The nematodes may 

 come in with the earth. As before 

 stated, the worms infest a large num- 

 ber of kinds of plants, and it is an easy 

 matter for them to come with the 

 soil. Soil that has not been used for 

 growing plants in the garden is not 

 necessarily free, but if taken from a. 

 pasture or meadow may contain many 

 nematodes. Then again they may be 

 taken into the house with the manure 

 that is used. 



"The determination of the best pre- 

 caution remains for the practical rose 

 grower. Cold in excess will probably 

 destroy the worms, and liliewise a high 

 temperature is inimical to them. Both 

 these conditions may be impracticable 

 to apply to the soil, the one being im- 

 possible in some cases and the other 

 too expensive. 



"Recently Doctors Stone and Smith, 

 of the Massachusetts Experiment Sta- 

 tion, have made extensive tests with 

 nematodes, and they conclude their re- 

 port by stating that while many solu- 

 tions are capable of killing the mature 

 worms, the strength and amount 

 necessary to add to the soil is great. 



"The most effectual, complete and 

 practical method at the present time 

 of exterminating nematodes in green- 

 houses is by heating the soil by means 

 of steam. This can be accomplished 

 without much expense, providing 

 proper attention is paid to the method 

 of applying the steam. 



"They find the minimum amount of 

 heat necessary to kill the nematodes 

 is 140 degrees F. Rose growers might 

 make the experiment of heating the 

 soil of a small portion of the bed be- 

 fore setting the plants, and satisfy 

 themselves if such treatment will pay. 

 If manure is the chief vehicle of the 

 worms, it may be possible to grow 

 roses without so much of this con- 

 stituent of the rose soil. It may be 

 that roses can be grown with a formed 

 soil, to which all the necessary ele- 

 ments of plant food have been added 

 as commercial fertilizers. Perhaps, 

 however, the pampered rose will not 

 perform its part unless fed in the or- 

 dinary way to which its ancestor has 

 been accustomed. 



"The fact is that the worms are do- 

 ing much damage and when they are 

 once in a plant there is no known way 

 of driving them out. New conditions 

 may induce the formation of new roots 

 and a sickened plant may revive, but 

 this is not to be expected under such 

 circumstances. 



"With roses the writer has not 

 found the eel worms in other than the 

 roots, and it is not thought that cut- 

 tings from galled plants will carry the 

 trouble." 



The Black Spot. 



I'.Actinoneraa rosae Fr.) 



The most widespread and conspicu- 

 ous of the one hundred or more 

 fungous diseases of the rose is the 

 Black Spot, due to the Actinonema 

 rosae Fr., and first described in 1826. 

 It is seen that this is an old enemy 



