332 THE MONTHLY BULLETIN. 



CALENDAR OF INSECT PESTS AND PLANT 



DISEASES. 



By E. J. VosLER, Assistant Superintendent, State Insectai-y. 



[Under the above heading the author aims to give brief, popular descriptions and 

 methods of controlling insect pests and plant diseases as nearly as possible just prior 

 to or at the time when the suggestions given should be carried into effect by the 

 growers. ] 



CITRUS FRUIT INSECTS. 



The Black Scale. 



The black scale is our worst enemy of the citrus tree. The adult 

 scales are black with a distinct "H" on the back, and are from one 

 eighth to one fourth of an inch in diameter. They lay their eggs 

 mostly during the months of IMay, June and July, although they may 

 sometimes be found in all stages at this time of year. The young 

 scales are most alnindant from September to December. The young 

 scales feed principally upon leaves shifting to the limbs as they become 

 larger. The injury by this scale is partly that caused by the excretion 

 of honeydew which furnishes a medium for the black-smut fungus 

 which covers the fruit and leaves, causing much damage. Injury also 

 results from decay, due to the vigorous washing the smutt}' fruit must 

 receive in order to improve its appearance. The black scale occurs 

 throughout the State, but is more abundant along the coast. It 

 attacks all citrus trees, the olive, apricot, grape, oleander, almond, pear, 

 etc. It is best controlled by fumigation on citrus trees. Fumigate 

 with one half to three fourths schedule, between September and Jan- 

 uary, the one half schedule being used when there is an even hatch 

 when the scales are very young. The time to fumigate will depend on 

 the evenness of the hatching period. The orchardist should fumigate 

 at the time that all the eggs are hatched and the young have not yet 

 become well grown. On deciduous fruit trees and olives, spray before 

 the scales have become half grown, with water, distillate, caustic soda, 

 mechanical mixture or distillate emulsion. The formula for the former 

 spray is as follows : 



Water 200 gallons. 



Caustic soda (Uo per cent) 7 pounds. 



Distillate (2S degrees Baume) 10 gallons. 



Fill the spray tank with the water and then add the caustic soda, which has previ- 

 ously been dissolved in a small amount of water and add the distillate ; agitate 

 thoroughly. 



The formula for the distillate emulsion consists of: 



Distillate (28 degrees Baume) 20 gallons. 



Whale-oil soap 30 pounds. 



Water to mix 12 gallons. 



Dissolve the whale-cil soap in water, heating it to the boiling point, then add the 

 distillate ; thoroughly agitate while the solution is warm. For use add to each gallon 

 of the above mixture twenty gallons of water. 



It is better to spray the deciduous trees after the leaves have fallen, 

 and the olives after the fruit has been picked. For equipment, pro- 

 cedure, details of fumigation, etc., the reader is referred to pages 318 

 to 336 of Nos. 1 and 2, of Vol. II, Monthly Bulletin of the State Com- 

 mission of Horticulture, by E. 0. Essig. Do not fumigate under 36 

 degrees Fahr., or over 70 degrees Fahr. 



