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QUOVSR AHD ALFALFA 
PEA APHIS tlllinoia pisi Kalt.) 
(See also Truck Crops*) 
Illinois. W. P. Flint (May 17). "More abundant than usual in the southern 
part of the State, but the outbreak is much less severe than last 
month, the weather having been favorable for the development of 
parasites, which have destroyed from 35 to 50 per cent of the aphids.'' 
Oregon. A. L. Lovett (A ril 12). "The pea aphis has appeared in serious 
abundance in western Oregon on field vetch, our principal hay crop 
for this region. The infestat ion was first observed on April 12. 
Climatic conditions favorable to aphid development had prevailed, 
that is, an unusually early spring followed by continued cool rainy 
weather. The infestation is very irregular, volunteer vetch being 
the most heavily attacked. Late sovn fields, particularly vhere 
accompanied by fall plowing am a general cleanup of surroundings, 
show few or no aphids. A vetch now being tested on the Station 
variety plat: : : by Mr. Schoth of the Federal Service, known as 
Hungarian vetch (..Yicjia paanoolca) has many desirable qualities as 
a hay or silage crop and is particularly immune, apparently, to 
serious aphis injury. 
Beneficial insects have developed slowly. Ccccinelli dae and the 
large syrphus fly ("■:.? sio^thicus iovrs s:ri ) are the principal forms. 
Hymenoptercus parasites are, and have been in previous outbreaks, 
most conspicuous by their absence. The fungus, Empusa anhidis , 
is present in all the fields. The unusual abundance of aphis and 
the cool moist weather prevailing would appear ideal fcr the develop- 
ment of this fungus, nevertheless it i s of minor economic importance 
in control, the estimated mortality from fungous disease being from 
8 to 14 per C6nt. Field and garden peas show no serious infesta- 
tion by aphis." 
H. A.. Schoth (April 21). "Pea aphis at Forest Grove getting a start 
on volunteer vetch on April 2. One or two parent forms to a plant." 
1. P. Rockwood (May 17). "Pea a:±is is attacking vetch more serious- 
ly than usual. The infestation as yet is confined to the early sown 
vetch, but winged migrants are appearing. last week the natural 
enemies, especially coccinellid beetles and syrphids, did excellent 
work during the few warm days, reducing the infestation to such an 
extent that no injury is anticipated unless the weather becomes 
unfavorable for them to v, rk over a considerable period. Four 
species of Hip:oda;ria and Coccinella trifasciat a have been present 
for at least two or three weeks, but the weather conc.it ions were 
not favorable for them to work; these and the syrohics are now 
laying eggs." 
