734 



HORTICULTTTRE 



December 2, 1916 



RULRC BOXWOODS JOHNSON & MILLANG, Inc., Auctioneers 



BULtSS OW/VT*VVri^*» „..;u:„„ «.C7 We.l 26th Street. New York 



Do Not Forget Salesdays — Monday and Thursday 

 Consignments Solicited 



Coo8«n Building, 55 57 We.l 26th Street, New York 



(Under Cut Flower Exchange) 



Salesdays Monday and Thursday at 10 A.M. 



10 000 square feet devoted to our auction business 



WRITE FOR CATALOGUE 



GREENHOUSE FUMIGATION 



In view of the frequent inquiries 

 made concerning methods for Jumi- 

 eating greenhouses with cyanide, the 

 following directions recently pub- 

 lished by the New Jersey AgricuUura 

 Experiment Station at New Bruns 

 wick are here quoted: 



'•Inasmuch as greenhouses differ 

 considerably in tightness and con- 

 struction, and as P^^t expenmento s 

 have in many cases failed to note 

 moisture and temperature conditions 

 the subject of greenhouse fumigation 

 is in a somewhat unsettled state, and 

 such a condition will continue to pre- 

 vail until some one makes -a serious 

 and long-continued study of the sub- 

 ject, taking into consideration all fac- 

 tors which have a bearing on the re- 



^"■•Concerning the amount of potas- 

 sium cyanide to use against the white 

 fly A. W. Morrill, in Circular o7 of 

 the Bureau of Entomology. U. S. De- 

 partment of Agriculture, sUtes that 

 between 1/5 and 1/6 of an ounce per 

 1000 cubic feet of space for 3 hours 

 exposure has been used with success 

 also that 1/3 of an ounce per 1000 

 cubic feet of space used for more than 

 30 minutes destroyed only the adults 

 and slightly injured the plants (to- 

 mato and cucumber), and that in one 

 instance 1 ounce per 1000 cubic feet 

 of space gave good results in an all- 

 night exposure. He also states that 

 probably M of an ounce of cyanide for 

 each 1000 cubic feet for an exposure 

 not exceeding 3 hours represents the 

 amount which will prove most effec- 

 tive for treatment without injury to 

 tomato or cucumber. R. D. White- 

 marsh, in Circular 154 of the Ohio 

 Agricultural Kxperiment Station, 

 states that in general the amount of 

 cyanide necessary for white fly work 

 varies from 1/5 to 1/6 of an ounce per 

 1000 cubic feet for 3 hours to 1 ounce 

 per 1000 cubic feet lasting overnight, 

 depending on the construction of the 

 greenhouse. He further states that It 

 is well to have the temperature as low 

 as 55 if possible for best results, and 

 that the fumigation should be repeat- 

 ed in 2 weeks. Mr. J. J. Davis, in the 

 27th Report of the State Entomologist 

 of Illinois, advises for white fly in 

 moderately tight houses, 1 ounce of 

 cyanide to 3500 cubic feet of space for 

 an all-night exposure, the operation to 

 be repeated 3 or 4 times at intervals 

 of 10 days to 2 weeks. In his general 

 fumigation directions he advises that 

 if possible a temperature above 60 to 

 65 deg. F. should be avoided, since 

 at a higher one the plants are more 

 liable to be injured. 



"A. B. Gahan, in Bulletin 119 of the 

 Maryland Agricultural, Experiment 

 Station, states that in houses contain- 



of not more than % of an ounce of 

 cyanide for each 1000 cubic feet of 

 space. This charge, he says, will be 

 sure to kill thrips, aphids and white 

 fly if left in a closed house over night. 

 the following plants being uninjured 

 by such an exposure— violet, primula, 

 chrysanthemum, begonia, nasturtium, 

 alternanthera, lantana. verbena, or- 

 chid, snapdragon, asparagus fern, 

 sweet pea, coriopsis, mignonette, .car- 

 nation, croton, cyclamen, Easter lily, 

 geranium, rose, cucumber and lettuce. 

 He further states that a long exposure 

 to a moderate amount of gas is less 

 likely to cause injury to most plants 

 than a short exposure to a heavy 



"Our experience in New Jersey with 

 white fly on tomatoes leads us to ad- 

 vise for a modern tight greenhouse % 

 of an ounce to 1000 cubic feet of space 

 tor an exposure of 20 to 25 minute^s. 

 having the temperature from 60 to 70 

 deg. F.. and the humidity 70 per cent. 

 "Prof. M. A. Blake, in the New Jer- 

 sey Agricultural Experiment Station 

 Report for 1913, tells of the successful 

 results obtained against the rose aphis 

 in a tight, well-glazed greenhouse. 

 using % of an ounce of cyanide to 

 1000 cubic feet for an exposure of 16 

 minutes with the temperature above 

 65 deg. F., and where moisture condi- 

 tions were normal for a rose house. 

 From a series of tests conducted at 

 the New Jersey Stations, he remarks 

 that fumigations against the rose aphis 

 are not likely to be successful where 

 the temperature of the house is 60 deg. 

 P. or below, inasmuch as metabolism 

 in insects is largely determined by 

 temperature, and when this is low the 

 insects resist the effects of the cyanide. 

 The tenderness of the plants should 

 also be considered. The more tender 

 and soft the growth the more likely 

 injury will follow the use of cyanide. 

 "\V. J. Schoene, in Technical Bulle- 

 tin No. 30 of the New York State Agri- 

 cultural Experiment Station, in a 

 series of fumigation tests with brown- 

 tail moth caterpillar, found that a 

 greater number of caterpillars sur- 

 vived the fumigations made at a low 

 temperature than at a higher temper- 

 ature, also that fumigations made under 

 humid conditions w-ere more destruc- 

 tive to the larvae than tests conducted 

 in dry air. He suggests that the differ- 

 ence in the results and the resistance 

 of the larvae to fumigation were due 

 largely to the conditions incidental to 

 hibernation, such as the reduced 

 moisture content and comparative in- 

 activity of the larvae. 



"Taking into consideration the work 

 of Mr. Schoene and our own experience 



in fumigation, we cannot at present 

 help but be advocates of heavy charges 

 of cyanide and short exposure. How- 

 ever, as has been stated before, the 

 entire subject needs a thorough inves- 

 tigation from all angles. 



Directions for Fumigating With Hy- 

 drocyanic Acid Gas. 

 "Fumigate only at night. Have the 

 foliage of the plants dry. The mate- 

 rials used in the generation of the gas 

 are 98 per cent, potassium cyanide, 

 commercial sulphuric acid and water. 

 For every ounce of cyanide use 2 fluid 

 ounces of sulphuric acid and 4 fluid 

 ounces of water. 



"1st— Determine accurately the num- 

 ber of cubic feet of space in the green- 

 house to be fumigated. 



"2nd— Find out the total amounts of 

 cyanide and sulphuric acid necessary, 

 and divide these into parts or charges 

 representing each 25 feet of length of 

 the greenhouse. 



••3rd— Weigh out the desired amounts 

 of pulverized cyanide for each charge 

 and wrap each in a single thickness of 

 cheesecloth or place in a thin paper 

 bag. 



••4th— Measure out the necessary 

 amounts of sulphuric acid and water 

 and place in glazed earthenware dishes 

 or glass receptacles (do not use metal). 

 Pour the water in first and add the 

 acid slowly, mixing with a glass rod 

 or stick. The container should never 

 be more than i/i full of acid and 

 water, because the action which fol- 

 lows the introduction of the cyanide 

 will result in much of the material 

 being splashed out. Ordinary glass 

 tumblers or bowls, 6 or 8 inches high, 

 about 3 or 4 inches wide, are often 

 suitable. 



••5th — Make the house as tight as 

 possible by closing all ventilators and 

 stopping up all cracks. 



"6th— Distribute the bowls contain- 

 ing the acid and water at the desired 

 distance apart and place beside each 

 the bag of cyanide. 



"7th — Commence at the far end of 

 the greenhouse and work toward the 

 exit, dropping each bag of cyanide 

 gently into the bowl. If a number of 

 charges are necessary, two or more 

 operators will need to work together. 



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