Corrosive sublimate (mercuric bichloride). — Used for disinfecting pruned stubs and cleaned-out cankers, at the rate of one part in 1000 parts of water. Can be secured from the druggist in tablet form in vials of 25 each, and costing 25 cents: One tablet makes a pint of solution. Make and store solution in glass and label poison.

Formalin (forty per cent solution of formaldehyde gas in water). -A pungent, clear liquid, very irritating to eyes and nose. Obtained at any drug store at about 40 cents per pint. Used for potato-scab, oat smut, bunt in wheat, soil disinfection, etc.

Lime. - Offered for sale in the following forms, (a) Ground rock or ground limestone ; air-slaked lime is of the same composition, i.e. a carbonate of calcium. (b) Lump, barrel, stone, or quick lime ; this is burned limestone, and should preferably test 90 per cent oxide of calcium. (c) Prepared, ground, or hydrated lime ; this is water or steam-slaked quicklime, dried and pulverized. Used as an applicant to the soil to correct acidity (p. 77), for club-root of cabbage, etc., and for preparing spray mixtures.

Lime-sulfur (see page 294). - In the many possible combinations, lime-sulfur is coming to be equally as important as bordeaux mixture, in the control of many plant diseases.

(a)  A mixture of equal parts of dry lime and powdered sulfur is often dusted on plants for surface mildews.

(b)  A paste of equal parts of lime, sulfur, and water. This is painted on the heating pipes in the greenhouse, and is valuable for keeping off surface mildews.

(1)  Home-boiled dilute lime-sulfur. This solution has been widely used in the past as a dormant spray, particularly for San Jose scale and peach leaf-curl. It is likely to be supplanted by (2) or (3). For preparation see page 295.

(2)  Home-boiled concentrated lime-sulfur. — When a great deal of spraying is to be done, a concentrated lime-sulfur solution may be boiled at home and stored in barrels to be used as needed. For method of preparation see page 295.

Test with a Beaume hydrometer, which has a scale reading from 25° to 35°. Dilutions are reckoned from a standard solution testing 32°. If the solution tests only 28°, it is not as strong as standard, and cannot be diluted as much as a solution testing 32°. The table on opposite page shows the proper dilution for solutions testing 25° to 35° Beaume.

Decimals are given in ail cases, but for practical purposes the nearest even gallon or half gallon can be used, unless appliances for more accurate measurement are at hand. It is understood in making all dilutions that water is added to one gallon of the conLIME-SULFUR centrate to make the stated amount. Do not measure out the stated amount of water and add the concentrated solution to it.

 

1-10

1-15

1-20

1-25

1-30

1-40

1-50

1-60

1-75

1-100

25°

7.4

11

14.7

18.4

22.1

29.5

36.8

44.2

55

73

26°

7.7

11.6

15.4

19.3

23.2

30.9

38.6

46.3

58

77.2

27°

8.1

12.1

16.1

20.2

24.3

32.4

40.5

48.5

60.6

80.7

28°

8.4

12.7

16.9

21.1

25.4

33.8

42.3

50.7

63.5

84.5

29°

8.8

13.2

17.6

22.1

26.5

35.3

44.2

53

66.3

88.2

30°

9.2

13.9

18.4

23

27.6

36.9

46.1

55.3

69

92

31°

9.6

14.4

19.3

24

28.8

38.4

48

58

72

96

32°

10

15

20

25

30

40

50

60

75

100

33°

10.4

15.6

20.8

26

31.2

41.5

52

62.4

78

104

34°

10.8

16.2

21.6

26.8

32.4

43.2

54

64.7

80.8

108

35°

11.2

16.8

22.4

28

33.4

44.9

56

67.4

84.2

112

(3)  Commercial concentrated lime-sulfur. - As manufactured and placed on the market is a clear amber liquid, and should test 32° to 35° Beaume It costs about 20 cents per gallon retail, and comes ready to pour into the spray tank. For apple and pear diseases. Arsenate of lead can be used with this solution, and increases its fungicidal value.

(4)  Self-boiled lime-sulfur. This is a mechanical mixture of the two substances, and is really not boiled, the heat being supplied by the slaking lime. In a small barrel or keg place 8 pounds of good quicklime. Add water from time to time in just sufficient amounts to prevent burning. As soon as the lime begins to slake well, add slowly (preferably through a sieve) 8 pounds of sulfur flour. Stir constantly, and add water as needed. As soon as all bubbling has ceased, check further action by adding a quantity of cold water, or pour into a barrel or tank and make up to 50 gallons. Keep well agitated. Very effective against peach scab and brown rot. Several other formulas have been used: 10-10-50 and 5-5-50. Arsenate of lead can be used with this mixture.