42 THE HOP APHIS IN THE PACIFIC REGION. 
Page. 
Aphis, hop, reproduction, method 12-13 
spraying experiments in control 24-27 
time to begin 23-24 
summary, general 37 
young, number deposited by viviparous females 16-17 
melon, comparison of head with that of hop aphis 15 
Aphis gossypii. (See Aphis, melon.) 
Boiling and mixing plant for spraying against hop aphis 32 
Camptobrochis nebulosus, enemy of hop aphis 23 
Chilocorus orbus, enemy of hop aphis 22 
Chrysopa californica, enemy of hop aphis 22 
Cladosporium sp., blackening of hops caused thereby 22 
growing on honeydew excreted by hop aphides 21-22 
Clean culture against hop aphis 36 
Coccinella abdominalis, enemy of hop aphis 22 
californica, enemy of hop aphis 22 
Compressed-air spraying machine, use against hop aphis, description 33-35 
Cost of spraying against hop aphis 35-36 
Cultural methods against hop aphis 36-37 
Direction in which to work in spraying against hop aphis 30-31 
Fertilization in control of hop aphis 37 
Flour paste, advantages over whale-oil soap as a spreader for contact insecti- 
cides 28 
and nicotine sulphate against hop aphis 26-27 
cost per 100 gallons 35 
. effect on quality of hops 30 
preparation 27 
Formica subsericea, relation to hop aphis 19 
Fungus, smut, (See Cladosporium sp.) 
Heat, effect on hop aphis 20-21 
Hippodamia convergens, enemy of hop aphis 22 
Honeydew excreted by hop aphis, black-smut. fungus (Cladosporium sp.) grow- 
ing thereon 21 
effect on hops 22 
Hop aphis. (See Aphis, hop.) 
food plant of hop. aphis 21 
picking off infested leaves for control of hop aphis 37 
sometimes winter host plant of hop aphis 14 
vines, damage by black-smut fungus (Cladosporium sp.) growing on honey- 
dew excreted by hop aphis 21-22 
stripping them in control of hop aphis 37 
Hops, blackening caused by smut fungus, Cladosporium sp 22 
quality as affected by spray materials used against hop aphis 30 
Irrigation in control of hop aphis 37 
Lime sulphate ineffective against hop aphis 25 
Machinery for spraying against hop aphis 31-35 
Nicotine solutions, mixing them with whale-oil soap 27 
sulphate against hop aphis 25-27 
and cresol soap against hop aphis 25 
flour paste against hop.aphis 26-27 
cost per 100 gallons 35 
lye-resin soap against hop aphis 25 
whale-oil soap against hop aphis 25-27 
