BUREAU OF p:ntomology. 333 



The tobacco fleti-beotle during 1919 damaged tobacco in some fields 

 at Quincy to the extent of $600 per acre. A power duster has been 

 secured for the bureau's experiments, and it has been found that a 

 mixture of e<iual i)arts of calcium arsenate and tobacco dust, or 

 lead arsenate and tobacco dust, when applied at the rate of 8 to 20 

 pounds to the acre (usual dosage ranging from 8 to 12 pounds), 

 resulted in a very satisfactory control. However, it was found that 

 late in the season considerable burn resulted from the use of calcium, 

 and the problem during this stage of growth resolves itself into a test 

 of the feasibility of using lead arsenate instead of calcium arsenate in 

 the tobacco dust poison mixture. The objection to the use of lead 

 ai-senate is due to its quality of adhering to the leaves, and thu> 

 presenting unsightly spots upon the cured wrappers. It is hoped 

 that lead arsenate used in the tobacco dust mixture will wash iront 

 the plants sufHciontly to overcome this objection. 



The use of calcium arsenate in the budworm-control mixture re- 

 sults in severe burning except under the most favorable conditions^ 

 and this insecticide must be abandoned for budworm control. 



^lornworm control on shade tobacco in Florida is also a serious 

 problem late in the season. Arsenate of lead can not be used straight, 

 because of the " painting " of the leaves and the consequent un- 

 sightly appearance of the cured wrapper. Paris green and calcium 

 arsenate are dangerous and injurious except under the most favor- 

 able weather conditions. P^xperiments are under way to ascertain 

 whether a mixture of arsenate of lead and tobacco dust can be used 

 more satisfactorily. 



SuGAK-CANE INSECTS. — The work for the fiscal year 1920 in Louisi- 

 ana has been devoted mainly to the introduction of Cuban parasites 

 .of the sugar-cane moth borer. In the summer of 1919 E. R. Barber 

 was stationed in Cuba, and sent in about 900 puparia of a tachinid 

 parasite {Euzenilliopsls diatraeae)^ Avhich were successfully estab- 

 lished on four Louisiana plantations. It remains to be proved 

 whether the parasites lived through the winter. 



The work was continued this summer, but on a much larger scale, 

 funds having been subscribed by a number of prog^ressive sugar 

 planters in support of the work. Mr. Barber went to Cuba in April, 

 accompanied by four student assistants. Several thousand puparia 

 have already been sent in. These are being cared for in a specially 

 designed insectary in which everything is arranged to provide for a 

 maximum of light and air, and owing to special facilities a minimum 

 of time is required in handling the parasites. 



Having emerged from the puparia, the flies are allowed to feed 

 and later are taken to the fields in small cages. Positive proof is 

 expected this year as to whether the introduction of Cuban parasites 

 is feasible and whether they can survive the Louisiana winter. If 

 the winter is too cold for them, it may be possible to keep them over 

 in greenhouses, and some sugar planters have suggested reintroduc- 

 ing them every year. 



The work of the station at Brownsville, Tex., has been devoted 

 mainly to an intensive study of the biology and ccmtrol of the 

 sugar-cane borer aud its conti-ol in the Ixio (Jrande Valley of Texas^ 

 Considerable attention has also been paid to the occurrence of the 



