THE PECAN LEAF CASE-BEARER. 



15 



insects more than offsets the injury that it is accused of doing in the 

 fall of the year, when it may take a few nuts from the pecan trees. 

 The writer has reared a number of parasitic insects from the larvae 

 and pupae of this case-bearer, as follows: Itoplectis conquisitor Say, 

 Triclistus apicalis Cress., CaUiephialtes grapholiihae (Cress.), and 

 Pristomerus sp., belonging to the family Ichneumonidae; Macro- 

 centrus delicatus Cress., Meteorus sp., Habrobracon variabilis Cush., and 

 Orgilus sp., belonging to the family Braconidae ; and Secodella acro- 

 basis Cwfd., which has been described as a new species by Mr. J. C. 

 Crawford (19), of the U. S. National Museum, and Cerambycobius sp., 

 belonging to the superf amily Chalcidoidea. Two species of Tachinidae 

 were reared from this case-bearer and were identified by Mr. W. R. 

 Walton, of the Bureau of Entomology, as Leskiomima, tenera Wied. 

 and Exorista near pyste Walker. This last he considers as probably 

 a new species. Gossard (12) reported rearing Spilochalcis vittata 

 (Fab.) and Itoplectis conquisitor Say from this host. It is interesting 

 to note that on one occasion specimens of Trichogramma minutum 

 Riley were reared from the eggs of the pecan leaf case-bearer. Of 

 the numerous parasites preying upon this pest, the most effective is 

 the small chalcidoid, Secodella acrobasis Cwfd., which was reared in 

 great abundance from the overwintering larvae. 



METHODS OF CONTROL. 



DIPPING AND SPRAYING TESTS FOR THE DESTRUCTION OF LARVAE IN HIBERNATION. 



In order to determine the effect of various spray materials on the 

 larvae in their hibernacula, a series of tests was made. For this 

 work small twigs that were badly infested were selected for the 

 treatment, which consisted in immersing the twigs in the materials 

 used. After the treatment had been effected the twigs were kept 

 in separate glass jars. The results of this series of experiments are 

 shown in Table IX. 



Table IX. — Dipping tests with sprays for destruction of hibernating larvse of the pecan 

 leaf case-bearer at Monticello, Fla., in 1913. 



Experi- 

 ment No. 



Number 

 of twigs 

 treated. 



I 



25 



II 



25 



III 



25 



IV 



25 



V 



15 



VI 



25 



VII 



25 



VIII 



25 



IX 



25 



X 



25 



Material used. 



Date of appli- 

 cation. 



Per cent- 

 age of 

 larvse 

 emerging 

 from 

 hiber- 

 nacula. 



Miscible oil (1:12) 



Miscible oil (1:15) 



Miscible oil (1:18) 



Miscible oil (1:20) 



Miscible oil (undiluted) 



10 per cent kerosene emulsion 



20 per cent kerosene emulsion 



Commercial lime-sulphur solution (1: 

 40 per cent nicotine sulphate (1:32) . . 

 Check; untreated 



■Feb. 11,1913 



