
-15- 
near the original liberation point of the introduced parasite, Campo- 
plex frustranae, the number of terminal shoots infested by Rhyacionia 
frustrana bushnelli had been reduced to a minimum of 15 per cent in 
1950 (14 per cent additional infested by R. neomexicana) with a para-— 
sitism, from all parasites, of 78 per cent for the first generation; 
in 1931 with only 11 per cent parasitism, 32 per cent of the terminals 
were infested (28 per cent additional by R. neomexicana)." 
CEREAL AND FORAGE INSECTS 
L. P. Rockwood, Forest Grove, Oreg., reporting on a recent study 
of the parasitism of the wheat joint worm (Harmolita tritici Fitch), 
believed to have been present in western Oregon for a comparatively 
short time says: "Dissection of the late fall collection of infested 
stubble from the sample farm in the Molalla district was completed dur- 
ing the month. * * * Using the stages of parasites and joint worms 
actually present in the stubble at the time of the examination as the 
basis of our calculations, conditions were as follows: 
Parasitism by Eurytoma parva (Girault) Phillips... 52.8 per cent 
af " Ditropinotus aureoviridis Crawf. (present) 20.1 per cent 
eoncoenoLos (MOStly Ditroplnotus )i nici. iietdsevesscscecosdonedene 9.1 per cent 
Parasitism by eupelmids (Eupelminus saltator Lind., E. 
allynii, Calosota).. 5.4 per cent 
EERE a reat eT SS LOSE. kin Cleese sca giien cc 04s Bhcs un asad socsn phe dhes tas avdeeoies -l. per cent 
UNUM SEA See Gd ML Syne Ay Cera hire ste bTR IA vaccine sasotticnda Fesues erase deed coon o¥ebaeuieas 67.5. per cent 
On this basis the survival of H. tritici would have been 32.4 per cent. 
However, since the eupelmids, Ditropinotus, and Calosota, especially the 
eupelmids, frequently act as secondary or tertiary parasites, these per— 
centages do not show the true history of the stubble. Examination indi- 
cated that Eurytoma that had entered more than one cell had destroyed 
148 additional Harmolita. This added to those actually counted in the 
examination increased the destruction by Eurytoma from 32.8 per cent to 
58 per cent, and total parasitism to 70.1 per cent. The examination 
also showed that 148 other Eurytoma had been destroyed by other para— 
Sites (Ditropinotus, eupelmids), so that had Eurytoma bsen left undis— 
turbed, its parasitism would have been 45.8 per cent, but still consid- 
erably less than the combined parasitism of all the parasites, 70.1 per 
cent. Many cases of superparasitism were noted. In one such case, a 
Ditropinotus larva was found which had destroyed another Ditropinotus 
(or possible a eupelmid) which had destroyed a Eurytoma which had des— 
troyed a joint worm." 
E. V. Walter and Lee Seaton, San Antonio, Tex., have been making 
"observations on the occurrence of the sorghum midge (Contarinia sorghi- 
cola Coq.) in the El Paso Valley, both north and east of El Paso, and in 
the Big Bend country near Presidio. Eupelmus popa Gir. was the only par- 
asite to emerge from any of these heads. It is somewhat of a mystery 
