14 Farmers’ Bulletin 1282. 
12 and 13 show one in operation against the onion thrips in the 
Coachella Valley. 
THE MELON APHIS.* 
The melon aphis is a serious enemy of melons, squash, cucumber, 
cotton, and several other crops, the damage varying from year to 
year, and in different localities, from slight and scattered infestations 
of little consequence to severe infestations causing a total loss of the 
crop. As these insects feed almost entirely on the lower surface of 
the leaves, frequently causing them to curl, it is difficult to obtain sat- 
isfactory control with a liquid spray. If sufficient time and care are 
taken to insure the covering of all leaves, particularly the underside, 
the operation becomes too expensive, and if such care is not taken the 
percentage of aphids killed is too low to make spraying worth while. 
A cloud of fine dust blown into the plant and hovering over and 
about it, however, penetrates to all parts of the foliage, coming in 
contact with the underside, and even into the curled leaves. This is 
especially true when the end of the discharge pipe is placed in the 
midst of the foliage, and with a spoon-shaped nozzle attachment by 
which the cloud of dust is directed upward, to the under surface of 
the leaves. 
Since melons, cucumbers, etc., are usually grown in hills, and it is 
desirable in dusting them to pay special attention to directing the 
blast of dust, the bellows type of hand duster (Fig. 3; Fig. 14, at 
right) is very satisfactory for this work. With such a machine one 
man can cover up to 2 acres of full-grown melons or cucumbers a 
day, using up to 50 pounds of dust. per acre. On smaller plants a 
ereater acreage can be covered, and with less dust. 
It is characteristic of the melon aphis to appear early in the 
season, when the plants are small, and often to infest plants seri- 
ously here and there in the field. If left unchecked, these plants 
will be sufficiently damaged to produce little or no fruit, and the 
aphids are likely to spread to all parts of the field. Such scattered 
infestations are troublesome to spray with a large outfit, while 
knapsack or smal] compressed-air sprayers are almost equally un- 
satisfactory. With a duster of the type shown in Figure 3, how- 
ever, it is easy and inexpensive to go over the field as often as neces- 
sary, dusting the infested plants, and thus not only killing the aphids 
in these early infestations and stopping the damage to the young 
plants, but also preventing the aphids from spreading and infesting 
the entire field. 
The small power outfit shown in Figure 4 can be used on large 
acreages of well-grown plants, or where it is desirable to get over 
Ss Aphis gossypii Glover 
