73 



APHELINUS FUSCIPENNIS AN IMPORTANT PARASITE UPON THE 

 SAN JOSE SCALE IN EASTERN UNITED STATES. 



By W. (x. Johnson, College Fork, Md. 



For the past eight years the writer has been paying- particular 

 attention to the parasites attacking scale insects. During this period 

 many species have been lired, but not many specimens frou) any par- 

 ticular scale. The instance cited below is, perhaps, the most impor- 

 tant from the economic standpoint yet discovered in these observa- 

 tions. 



Since we assumed charge of the State work in Maryland we have 

 collected the San Jose scale on various food plants, and inclosed 

 infested twigs, about 4 inches in length, in glass cylinder tubes open 

 at both ends. The ends were closed with cotton, and if any parasites 

 existed upon the scales they were easily detected and mounted for 

 study. Only upon rare occasions have we taken more than a half 

 dozen specimens from a single tube. This experience has been 

 repeated year after year until the fall of 1899. 



Of the four species of true parasites known to feed upon the San 

 Jose scale, three of them have l)een bred in Maryland. So far as I 

 know Anaphes gracUh How. . bred liy Dr. L. O. Howard from scales 

 from Charles County, Md.. has not been reared from this scale from 

 any other State. Aapidiojihagus dtrinas Craw, has been reared only 

 in California from this pest. Aplielinns mytUasplcUs Le B. and 

 ApheUnus fuscipe>inis'iio^\ . have been reared from scales taken at the 

 following places in this State: Riverside, Annapolis Junction, Araby, 

 and Mitchellville. Last fall, however, I discovered a new locality for 

 A. fxiscipennis near Easton, Talbot County, in an infested orchard 

 along the Miles River. The orchard contained a miscellaneous variety 

 of fruits, and all the trees were quite seriously infested with the San 

 Jose scale. Instructions had been given the owner to cut them down 

 as soon as possible and burn them. A quantity of small branches 

 incrusted with scale were ])rought to the laboratory and inclosed in 

 breeding tubes. Much to my surprise these tubes were swarming 

 with parasites a few days later. From one tube 1,114 specimens of 

 Ajjhelinus fnscipjennis were taken; while a second tube gave 132, a 

 third 1,178, and a fourth more than 1,000, but owing to an accident 

 the connt in the case last mentioned was not exact. The writer was 

 greatly elated over this discovery, and immediately sent out the fol- 

 lowing statement to the State press: 



I am advising my correspondents not to burn twigs and branches cut from trees 

 infested with the San Jose scale. If the tree is so seriously infested it can not be 

 saved; it should be dug up by the roots, trimmed, and the brush and wood piled 

 in the orchard, where they should be left until about the 1st of June or longer. If 

 the trees are to be sprayed with either, a 25 per cent solution of kerosene and water, 



