264 STATE HORTICULTURAL SOCIETY. 



the pest. They saw the leaves and most of the fruit fall before midsum- 

 mer; and some of their trees were left in a dying condition, while others 

 presented a blighted, blackish, desolate appearance. Fruitgrowers reported 

 two causes which rendered their efforts ineffectual. These were peculiar 

 phases in the habits of the insect. First, the nymps were so completely 

 enveloped in honey-dew that none of the insecticides reached them. Sec- 

 ond, the activity of the summer adults rendered it impossible to reach 

 them with a spray; as soon as the first spray struck a tree, the adults arose 

 instantly and flew to some distance, remaining away till the spraying 

 ceased. 



During 1892, the pest has done no perceptible damage in orchards which 

 it devastated last year. Fruitgrowers noticed that the pest considerably 

 decreased in numbers later in the season last year. This decrease and the 

 scarcity of the insect this year was probably due principally to the fact that 

 the insect feeds almost exclusively upon the tenderest leaves and branches 

 of the trees. As hardly any new growth was formed and as most of the 

 leaves fell off early in the season, the insect was thus deprived of its favor- 

 ite food and consequently its increase checked. So great was the decrease 

 that but very few of the hibernating adults appeared. On this account we 

 tried no experiments to destroy the adults in their winter hiding places. 

 It seems practicable, however, that a thorough washing of the trunks and 

 larger branches of the trees in winter with kerosene emulsion (at least five 

 per cent, kerosene) or a strong soap solution, would destroy many of the 

 adults. 



As soon as the eggs of the hibernating form were found, experiments 

 were begun with a view to the destruction of the insect in this stage. As 

 the eggs were so freely exposed on ttie bare twigs to the action of any 

 fluid, it was confidently expected that the pest could easily be checked 

 here. Both field and laboratory experiments were conducted. The 

 branches containing the eggs were dipped into the solution in each case, 

 thus making sure that the treatment was thorough. The results obtained 

 were very surprising. Eggs dipped in the following substances hatched a 

 few days afterward : 



Kerosene emulsion ( Hubbard-Riley formula) used full strength, and 

 diluted with three parts of water heated to 130° F. Kerosene undiluted. 

 Turpentine emulsion diluted with three parts of water. Turpentine undi- 

 luted. Crude carbolic acid emulsion diluted with ten parts of water. 

 Resin wash used triple strength; and heated to 130'' F. Whale-oil soap 

 and sulphide of potash wash used double strength. These last two washes 

 are successfully used in combating all stages of scale insects. Concen- 

 trated potash, one pound to one gallon of water. Benzine undiluted. 



Most of the above substances injured the buds; concentrated potash and 

 carbolic acid when used in less dilutions killed the buds. These results 

 made it evident that it was impracticable to fight the pest with insecticides 

 while in the egg state. 



However, if the pear-growers could wait until about April 15, before 

 pruning their trees, they could destroy many eggs. Most of the eggs are 

 laid by that date, near the tips of the last year's growth ; so it is only nec- 

 essary to cut back these shoots, as many growers do, and burn them, to 

 destroy large numbers of eggs. 



After the unsuccessful efforts to destroy the eggs with insecticides, we 

 could do nothing more until the nymphs appeared. Some of the nymphs 

 appeared before the buds had opened much; these nymphs immediately 



