120 



About the 1st of July a new brood appeared iu comparatively limited 

 numbers from the few larvje Avhich escaped the spring treatment. The 

 api)lieation of kerosene was repeated on Julj^ 7 as in the first instance, 

 and a similar result followed, with the excei)tion that it seemed to have 

 been even more eftectual, and no living scales whatever were discov- 

 ered when the trees were examined on the 17th and at various later 

 dates, even in a few instances where the young had remained under 

 the old scales. The above experience indicates that we have in this 

 new peach scale an insect very. amenable to summer treatment. 



Chionaspis euonyml Comst. has proven troublesome to the Euonymus 

 trees on the Department grounds and in pri«vate yards in the city of 

 Washington. Aj^plications of kerosene emulsion have been made from 

 time to time to eradicate the pest. When these applications were made 

 ust at the time of hatching fairly good results followed, but the difli- 

 culty has always been that the hatching period of this scale extends 

 over a number of weeks, and later in the season the broods become so 

 intermingled that all stages are found on the plants together. The 

 ordinary washes are totally ineffective on half- grown or mature insects 

 of this species. The experiments already referred to show that it takes 

 a strength of kerosene emulsion four times greater than that ordinarily 

 recommended to kill the adults, and this can be applied to the plants, 

 at least in their mature and midsummer condition, without injury. 

 Applications made on July 18, on a scorching hot day, were not fol- 

 lowed by rain for four days. Double oi'dinary strength, namely, 1 part 

 of kerosene to 4i of water, resulted in the death of 75 per cent of the 

 adults. Four times ordinary strength, or diluted with 2^ parts of water, 

 resulted in the death of 99 per cent of the adults and young. The ordi- 

 nary strength, nine times diluted, killed nothing but the newly-hatched 

 young. 



Experiments were also tried on the oak scale, Asterodiaspis querck-ola 

 Bouche, the young of which began to appear early in May. The woist 

 infested oak was, at the time of treatment, just expanded into full leaf, 

 and the foliage was excessively delicate and tender. The application 

 was therefore made only at the rate of 1 part of the enuilsiou to 13 

 parts of water. This resulted in the death of all the young which had 

 emerged at that time. This scale, however, is one of those the hatching 

 of which extends over a considerable time, and several applications are 

 necessary to reach complete extermination. Similar results attended 

 the spraying for Ch ionaspis furfurus on Japan quince. In the case of 

 this insect, however, the emergence of the spring brood is more uniform, 

 and one or two applications are suflicient. At Washington the young 

 of this scale enu'rge during the second week in May, and the applica- 

 tion IS best made about the loth. The abundant leafy growth of the 

 Japan quince makes it verj^ difficult to wet the branches with any 

 thoroughness, and midwinter treatment for this plant will ordinarily be 

 necessary. 



