164 PROCEEDINGS OF THIRTY-THIRD FRUIT-GROWERS ' CONVENTION. 



The dosage for red scale is usually from one third to one half more than 

 for black scale, the tents to be kept on the trees one hour. Where 

 thorough work is contemplated for the eradication of the scale, the 

 dosage should be double that for black scale and the tents should remain 

 on the trees one hour and a quarter, using three and one half parts of 

 water to one of cyanide. All low-hanging limbs touching the ground 

 should be removed and all drop fruit on the ground should be destroyed, 

 as near the ground the gas is not so effective. 



The red scale is always in condition for treatment, but the treatment 

 is usually timed to include the black scale. With ordinary dosage 

 thousands of the scale in all stages will be destroyed on a tree, but for 

 reasons we can not explain an occasional scale escapes the treatment 

 and furnishes the basis for future infection. On account of this result 

 the double dosage and extended time of covering are recommended for 

 thorough work. 



Yellow Scale. — Yellow scale very much resembles the red species, but 

 differs in color and habit. The red scale infests the fruit, foliage, and 

 wood, even to the old wood of the tree. The yellow scale infests the 

 fruit and foliage only ; specimens of this scale are not commonly found 

 on the wood. The yellow scale largely infests the seedling orange tree, 

 and we find there the heaviest infestation. Another fact that seems to 

 emphasize the correctness of the belief that the yellow scale is a distinct 

 species from the red scale is the fact that the Golden chalcid fly and 

 other parasitic insects keep the yellow scale under fair control, in most 

 cases treatment not being especially required for this scale, but occa- 

 sionally treatment is required when the parasite enemies temporarily 

 fail to hold it in check. In such cases the same treatment is to be recom- 

 mended as for red scale. 



The yellow scale seems to be fully as hard a scale to destroy by spray- 

 ing or gasing as the red. 



C. A. Day. 



LIFE AND HABITS OF PURPLE SCALE. 



The life of this scale varies from 75 days in summer to 120 days in 

 winter. 



The female scale begins to deposit eggs at the age of 40 days. The 

 number varies from 25 to 27 eggs. Then her life is ended. The period 

 between the time the eggs are deposited and time of hatching is con- 

 trolled by weather conditions and may be from 35 to 70 days. 



Continued warm weather hastens their growing life and shortens the 

 time of incubation of eggs. Cold weather has a reverse effect, not so 

 much in growing life as in time of egg incubation. 



This scale produces four broods during the year, the hatching of 

 which is governed to such an extent by the weather conditions that it 

 would be difficult to determine within 15 or 20 days of the time hatches 



