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22 



The Florists^ Review 



May 18, 1916. 



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HOW TO FIGHT | 



THE RED SPIDER I 



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A SCIENTIST'S ADVICE. 



[A paper by Parker Tbayer Barnes, assistant 

 zoologist of the Pennsylvania State Department 

 of Agriculture, read before the Florists' Club of 

 Philadelphia and begun in The Review for May 

 11.] 



An Old-Time Bemedy. 



The first thing I learned about red 

 spiders while* serving my novitiate in 

 the greenhouse was that as the cold of 

 winter begins to strengthen, making 

 hard firing necessary, with the result- 

 ing drier air, the red spider commenced 

 to flourish and so we all believed that 

 an arid condition was congenial to the 

 red spider. I suppose it is in a meas- 

 ure, but it is not absolutely necessary. 

 Last summer was far from being a dry 

 summer, there were no long droughts 

 in it, and yet I found red spiders in- 

 festing shade trees in the vicinitv of 

 Harrisburg, Pa., to such an extent that 

 the trees had lost their green color 

 and had taken on a grayish or brown- 

 ish color, which gave them the appear- 

 ance as if much road dust had settled 

 on the leaves and branches. 



We were taught that water was the 

 only remedy. It will wash the spidei-s 

 oflf, but do they have time to drown be- 

 fore the water has drained away from 

 the soil where they fell under the plant, 

 and so are they or are they not ready 

 to crawl back on the plant! I do not 

 know. I have not had sufficient time 

 to watch them to find out. 



Sulphtir Best Exterminator. 



Sulphur is the one best bet with 

 which to fight the pest. You can blow 

 it on by means of a blow gun; you 

 can use a lime-sulphur wash such as is 

 used to kill the San Jose scale on the 

 fruit trees, but, of course, much 

 weaker; you can use potassium sulphite, 

 or liver of sulphur, one-half ounce to 

 the gallon of water. This last you all 

 will probably recognize as a standard 

 remedy for mildew of roses. 



Instead of blowing the sulphur on, 

 you can spray it on. One pound of 

 sulphur mixed in three gallons of water 

 and just enough soap to make it stick, 

 is a standard remedy on fruit trees ns 

 a summer spray, but in the greenhouse 

 I would use it much weaker at first, 

 to make sure of not burning the 

 foliage. Prof. S. T. Maynard reports 

 having successfully killed the red 

 spider in a house of grapes by boiling 

 the sulphur, but this is a rather dan- 

 gerous and tedious method. 



If I were called upon today to fight 

 a case of red spider in a greenhouse 

 or on fruit trees, I would do one of two 

 things. The first thing would be to 

 spray the plants with a flour paste. 

 That sounds like a reckless procedure, 

 but you will find the paste is so thinly 

 spread out that when it dries you can- 

 not see it. 



A Government Beclpe. 



W. B. Parker, of the federal bureau 

 of entomology, invented the flour paste 



method of fighting red spider while 

 working on the hop problem on the Pa- 

 cific coast. It is made as follows, and 

 these directions are for use in the open; 

 you should modify them and figure the 

 amounts for use in greenhouse prac- 

 tice: 



"Use a cheap grade of fiour. Take 

 eight pounds and make the fiour into 

 a thin batter by adding a little cold 

 water at a time, until eight gallons of 

 water are used. Mash out all lumps. 

 Cook until a paste is formed, stirring 

 constantly to prevent caking or burn- 

 ing. Cooking slowly until the paste 

 just begins to boil will usually be about 

 right. If the paste is not sufficiently 

 cooked, the resulting spray will not be 

 effective, and if overcooked the paste 

 will harden when thoroughly cool and 

 will not mix with water readily. Add 

 cold water to the paste when done to 

 make 100 gallons of material in the 

 spray tank. Keep it constantly stirred 

 while spraying. Apply thoroughly to 

 both the upper and under surfaces of 

 leaves. Use a nozzle making a coarse 

 spray, and not under 150 pounds pres- 

 sure, as the driving force is necessary 

 to penetrate the webs and reach the 

 spiders. An extra fine spray will not 

 be effective. This is a contact insecti- 

 cide and the liquid must actually toucli 

 the spider. The materials are cheap; so 

 apply the paste liberally. Watch the 

 plants carefully, and if newly hatched 

 spiders are appearing repeat the spray- 

 ing in about seven days. No spray will 

 kill the eggs without injurying the 

 vines." 



Barrel of Paste Only 7 Cents. 



I have usffd this spray successfully 

 against red spiders on plum trees in the 

 Pittsburgh district and I see no reason 



why it would not work in greenhouses. 

 It is cheap and effective and will not 

 in any way damage the foliage or fiow- 

 ers. We used Eed Dog flour when mak- 

 ing our paste. This is a cheap brand 

 of flour that is a favorite food for hogs, 

 and my recollection is that it cost us 

 in actual cash outlay for materials 

 about 7 cents per barrel (fifty gallons), 

 ready to apply to the trees. 



We bought some potassium sulphide 

 to try at this time, as this material had 

 been successful in the cotton experi- 

 ments in the south, but the fiour paste 

 was so effective that our experiment- 

 ing stopped. 



The Sulphur Cures. 



My one other safe bet would be 

 sulphur, blowing on the dry sulphur; 

 or I would use atomic sulphur. This 

 latter is a paste of finely divided sul- 

 phur, manufactured and sold by the 

 Thomson Chemical Co., of Baltimore. I 

 have not used it, because at Harris- 

 burg we have no facilities for experi- 

 menting. This material now is used in 

 large quantities as a fungicide on peach 

 trees for the scab and brown rot. In 

 California Prof. W. M. Scott tells me 

 that it is used against the red spider 

 on citrus trees and a great variety of 

 plants with success. Use, when you 

 commence to experiment with this form 

 of sulphur, about one-half to three- 

 fourths of a pound in ten gallons of 

 water and a little soap, say one-fourth 

 of a pound. Dissolve the soap before 

 putting it in the solution. Soap acts 

 both as a spreader and sticker. 



I have spoken of lime- sulphur wash. 

 I do not recommend it, because it is 

 violent stuff and there is danger of 

 burning the foliage until more experi- 

 mental work is done. Prof. E. D. Whit- 

 marsh in a recent bulletin from the 

 Ohio Experiment Station makes the fol- 

 lowing recommendation with regard to 

 its use on violets: "In twenty-five gal- 

 lons of water mix one-half pint of 

 Nico-fume and two quarts of concen- 

 trated lim^sulphur wash." I have no 

 doubt that it will work like a charm, 

 but at that strength of lime-sulphur I 

 am sure some kinds of stock grown 

 under glass would rebel,' for it is strong 

 enough to burn peach foliage in the 

 open. 



BUILDING UP 

 OUR SOILS j^ 



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COMMERCIAL FEBTILIZEBS. 



As Compared with Animal Manures. 



Having been furnished with a sum- 

 mary of reports of experiments in the 

 fertilization of soils for roses and car- 

 nations grown under glass by a firm en- 

 gaged in the manufacture of fertilizers, 

 and having been asked by this concern 

 to give my opinion on the subject, I 

 thought that perhaps a general discus- 

 sion by practical growers in the pages 

 of The Review might be of 'interest to 

 the readers at large. 



The real gist of the reports seems to 

 lay stress upon the efficacy of phos- 



phatic fertilizers for both roses and car- 

 nations in increasing production and 

 seems to favor the use of acid phosphate 

 rather than that of bone meal. The re- 

 ports also seem to favor the use of such 

 commercial fertilizers as acid phosphate, 

 bone meal, dried blood, blood and bone, 

 etc., in preference to stable manures, ap- 

 parently placing the commercial fertiliz- 

 ers, so called, in competition with stable 

 manures. 



The Needs of Different Soils. 



While the reports from experimental 

 stations regarding fertilization are of 

 great value to us as growers and in a 



