3'i4 AXNTAT, KKPOKTS OF nEl»Ai;T\n:X'l' OK AGlUrULTURE. 



sj;ecies upon Jolmson ofrass, Siuhiii trniss, kafir ( orn, and other 

 l)lanls. 



In conjiiiu'tion with tho paiasile introWiiction rani])ai<^n hcinjj con- 

 (hictc'd ni Loui.-.iana. hir^o nunibors ol" hir\al parasites of the cane 

 borer have been reh:'ased in the most heavily infested su^ar-eane and 

 corn fiehls. Unfortunately, climatic conditions were such dui'ing the 

 winter of 1019-20 (hat an unusually small number of cane borers sur- 

 viveil and the infestation so far this year has been renuirkably li<:^ht. 

 For this rer.son it is yet too early to determine whether the parasite 

 has been able to establish itself. Tender normal conditions the intro- 

 duction of these parasites promises to be the most simple and effective 

 control measure that can be adopted. A very efticient e^<^ parasite 

 is already present over the greater portion of the infested territory, 

 which at certain seasons destroys about 75 per cent of the total borer 

 eg<rs deposited. 



Experiments during the hibernation period have also proved that 

 under Rio Grande Valley conditions old cornstalks lying in the fields 

 through the winter may be as dangerous, if not more dangerous, 

 than sugar cane under the same conditions, owing to the larger nunj- 

 ber of wintering larvae present in cornstalks. I^'or this reason strong 

 recommendations haA^e been made regarding the destruction of corn- 

 stalks during the winter. With the high price of cane prevailing, 

 the cane fields generally have l)een cleaned up very thoroughly, and 

 in two locations at least e^en the old tops have been used for plant- 

 ing in order to release more cane. This no doubt has been an impor- 

 tant factor in the scarcity of borers in the cane fields so far this year. 



During the year the cane borer has been discovered in a number 

 of widely separated localities in Texas where it has not previously 

 been known to occur. This includes a number of points along the 

 Gulf coast. For this reason it is important that the general dis- 

 tribution be determined, and a survey has been planned for the near 

 future to cover the infested territory and to discover how far the 

 pest has spread. 



INSECTS AFFECTING THE HEALTH OF MAN AND DOMESTIC 



ANIMALS. 



Insects affectixg domestic animals. — Under the project " Con- 

 trol of the House Fly and Other Insects in Establishments Operat- 

 ing under the Federal Meat Inspection," cooperation was continued 

 with the Bureau of Animal Industry. Progress w^as made in further 

 perfecting fl^-traps and baits. Some experimental evidence was ob- 

 tained as to repellent and attractive chemicals and the possibilities 

 of their use in controlling the house fly and vaj'ious bloAv flies. The 

 Bureau of Animal Industry inspectors in charge of the various 

 stations have been proceeding with the work as advised by the 

 Bureau of Entomology, looking toward the permanent abolition of 

 favorable fly-breeding grounds around packing houses and abattoirs. 



Screio worms. — It has been conservatively estimated that the aver- 

 age annual loss due to this pest is $4,000,000. There also is a con- 

 siderable loss due to the wool maggots of sheep. Investigations have 

 been carried out along several lines. A field station has been es- 

 tablished in the heart of the sheep and goat raising regions of Texas 



