THE PEA APHIS WITH RELATION TO FORAGE CROPS. 
7 
there were many bare spots where the aphid had killed the clover locally, and in the 
growing clover were many centers of new infestation, due doubtless to migrant winged 
females. All of the clover in that part of the country was more or less injured; not 
only old clover but also the first-year growth. Retiu-ning to the same region the fol- 
lowing summer to see the consequences of the injmy, I did not stay long, for it was 
hard to find a field of clover anywhere. The farmers reported that the clover had 
been "winter killed," to their sm*priye, since the Mint or had not been a severe one 
and the clover had often surWved worse winters. 
Mr. Harold Morri^so^ (1912), discussing the abundance of this insect 
in Indiana, says: 
Two years ago [1910] it was so common in many clover fields near the city [Indian- 
apolis] that the clover remained on the ground for more than a week after cutting 
without showing signs of ciurmg. The clover stems were so plastered with honeydew 
that the moisture could not evaporate from them. 
We have seen clover fields in Indiana so hadh" infested that the 
plants would be covered Avith the so-called '^hone^^dew," a sticky, 
sweetish fluid ejected by the aphis from the anus. Walking through 
such an infested field, one's trousers would appear green, so thickly 
would they be covered by the plant-lice, and ruined by the honeydew 
which covered the plants. Wliile it is seldom that fields are killed 
outright as described by Dr. Folsom, there can be no doubt that the 
heavy infestations, which are so common, have a decided weakenmg 
effect on the plant and much of the winter killing of clover can be 
traced back to the depredations of the pea aphis. Most probably 
much damage to clover has been overlooked or attributed to other 
causes, for while a crop may be injured on large field crops such as 
clover the injury will be overlooked unless the field is almost killed 
outright, and subsequent effects, such as the weakening of the vitality 
of the plants, is too often attributed to winter killing," as Dr. Folsom 
has pointed out. Especially may this species be a very dangerous 
clover pest if the weather conditions are favorable to aphides and a 
long dry spell retards the growth of the clover. 
CHARACTER OF ATTACK. 
This aphidid prefers the young tender leaves and stems of its host, 
but eventuixlly it covers the entire plant. Garden and sweet peas, 
l)eing succulent plants, are seriously attacked and readily succumb 
to the depredations of the aphides. Clover, particidarly red clover, 
on the other hand, is able to ^vithstand considerable injury, but, as 
has been noted, even this plant is not free from serious damage; in 
fact entire fields of cl()V(4- are sometimes destroyed. 
EFFECTS ON CATTLE OF FEEDING THEM INFESTED CLOVER. 
We have no definite reports of injury to cattle by feeding clover 
hay which has been heavily infested with aphidids ; indeed, we have 
been informed by cattle feeders that such clover, which has a slightly 
