40 MASS. EXPERIMENT STATION BULLETIN 427 



WATER SYRINGING AND NAPHTHALENE FUMIGATION 



The substitution of naphthalene fumigation for the practice of sxringing car- 

 nation plants with cold water or salt water to control red spider mite has im- 

 proved the quality of carnations and aided in the control of disease (29). Two 

 or three fumigations at intervals of 5 to 7 days are recommended, using naph- 

 thalene flakes at the rate of 2 ounces per 1,000 cubic feet, or a commercial naph- 

 thalene base fumigant as directed by the manufacturer. A temperature range 

 cf 70° to 80° F. and a relative humidity range of 60 to 80 percent should be 

 maintained during the period of fumigation. One lamp is used for each 7,000 

 cubic feet, and the heat is adjusted to vaporize one-sixth of the dosage each 

 hour of a 6-hour fumigation period. Fumigation should not be practiced during 

 excessive wind or at temperatures above 90°. 



Solutions of salt and nicotine sulfate in cold water, formerly used for syringing 

 carnations, are not lethal to the red spider mite. Some fungicidal value is shown, 

 and the spread of disease is indicated also. In one of the tests which is indicative, 

 an average of LI 7 infections per leaf followed wetting the plants with a spore 

 suspension of Alternaria in a 1-500 solution of 40 percent nicotine sulfate con- 

 taining 5 percent table salt, in contrast to an average of 3.42 infections per leaf 

 with a spore suspension in water. 



Some experiments were carried out to determine the comparative effect of 

 naphthalene fumigation and water syringing on the yield of flowers. The blight 

 disease especially was a factor involved in the contrasts. Six benches in each 

 of two adjoining like sections of a greenhouse of 5,000 cubic feet were planted to 

 54 Matchless plants each on August 1, 1929. The plants in the comparable 

 benches were dug from the same plots in the field which, from June 21 to July 26 

 had been sprayed or dusted five times with fungicides. A spray of calcium arse- 

 nate and lime caused severe foliage injury and subsequently the plants became 

 badly blighted. Plants treated with 20-80 monohydrated copper sulphate-lime 

 dust were badly blighted and also infested with the red spider mite. Other plots of 

 plants not receiving sulfur were more or less infested. After the plants were 

 benched in the greenhouse, the red spider mite infestation was allowed to increase. 

 One house was syringed regularly with cold water; the other fumigated with 

 naphthalene. With the advance of the season distinct contrasts in growth and 

 disease occurred in favor of fumigation, which are expressed in the yield of 

 Number 1 flowers from October 1929, as follows: 



Water Naphthalene Percent Termination 

 Fungicide Syringing Fumigation Increase of Records 



Dusts 



Sulfur -- 718 810 12.8 June 1 



Monohydrated copper sulfate-lime 



20-80_ -. 383 570 48.9 May 1 



S.-rays* 



Calcium Arsenate - 63 123 95.2 January 1 



Chemical Hydrated Lime 1 K lb - 



Lime-Sulfur 1 gal 532 763 43.3 June 1 



Calcium Arsenate 1^ lb 



Bordeaux 4-4-50.. -- 577 659 14.2 May 15 



Calcium Arsenate 1}4 lb -- 



No Treatment. ^-- 425 728 71.2 May 1 



♦Materials in 50 gallons. 



A further test contrasting naphthalene fumigation and water syringing in 

 adjoining greenhouse sections was conducted in 1930-1931. Each of the benches 

 was planted to 54 Matchless plants grown from cuttings collected from Decem- 



