44 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE, 1953 
Alfalfa Selections Excel in Resistance to Pea Aphid 
Twenty-four alfalfa plants LOO-percent resistant to the pea aphid 
were screened from 958 new accessions tested in the greenhouse ii. 
cooperation with plant breeders of the Bureau of Plant Industry, 
Soils, and Agricultural Engineering and the California Agricultural 
Experiment Mat ion. Of the resistant strains, 7 trace to the variety 
Ladak, 6 to Ranger, 5 to California Common, 5 to Argentine, and 
i to ( !hilean. Four plant.- of each of 1 U> clone- of F : crosses, together 
with 4 plant- each of 6 susceptible clone.- for check.-, were transferred 
to the field at the California field .-tat ion near Lancaster for testing 
under conditions of severe pea aphid attack which normally occurs 
there. 
Sugarcane Borer Infestations Reduced by Use of Resistant Varieties 
Two sugarcane plantations in Florida reduced their sugarcane- 
borer \ opulation by one-half by replacing borer susceptible varieties 
F. 31-436 and Co. 290 with resistanl varieties F. 31-%:.' and ('. P, 
34r-79. In Florida varietal test plots, F. 31-962 had only 2 percent 
of the joints bored compared with L5 for another commercial variety 
and 12, 10, 8, and 5 each for 4 unreleased varieties. 
Introduced Sugarcane Borer Parasites Released 
Neaily 5,800 individual- of the sugarcane borer egg parasite 
Prophanurvs ciL < to were released in Louisiana sugarcane fields during 
August and September L952. Of these, 2,119 were reared from six 
shipments of this species received from Trinidad. This number was 
increased by breeding at the Eiouma, La., station. Although this 
parasite was seen ovipositing in borer egg clusters, do held recoveries 
been made. 
Fifty Agathu rw*, a larva] parasite of the sugarcane borer, 
and 500 i Vgathis /> xanus, a larval parasite of the ramie leafroller, wore 
received at the JI »uma station from the Belle Glade, Fla., station. 
A. 8tigmateru8 parasitizes about 8 percent of the sugarcane borers in 
Florida and is capable of ove ring in Louisiana. This parasite 
ua- successfully reared at the Houma -tat ion in L952. Eighteen 
ati i us and 266 parasites were released in sugarcane fields 
in Louisiana in August and September. 
Start Made Toward Biological Control of W Heat Stem Sawflj 
Two parasites of the wheat stem sawfly introduced from Europe, 
Brad bella and Collyria colcitrator^ numbering 2,131 and 692, 
respectively, were released at Minot, \. Dak-, and Choteau, Mont., in 
areas where the sawfly is causing economic damage. A newly de- 
scribed native parasite, Bracon r, was collected at Choteau. 
B.& phi) another native sawfly parasite, has one complete and a partial 
second srenerat ion at .M inot. 
