Florida Agricultural Ex.periment Station


generations in the spring feed on the tender unfolding buds of
those trees. The first generation is pink in color but their
young are green and never become pink. The second or third
generations usually develop wings and leave the trees for tender
vegetables where they live all summer. This annual migration
is common among aphids, and the last generation returns to
the trees in the fall to lay eggs, enabling the species to get an
earlier start in the spring than would be possible were it neces-
sary to wait for herbs to grow.
 Aphids give off a sweet substance called honeydew of which
 ants are very fond. For the sake of this honeydew ants care-
 fully tend aphids, often protecting them from their enemies
 which they drive away. They may carry the aphids or their
 eggs from place to place where the pasture is good, carry
 the eggs into their nests to winter over, or even build adobe
 sheds over them for protection from rain and enemies. For
 this reason aphids are often called ants' cows." Hence it
 happens that the presence of excited ants on a plant is often
 the most evident sign of the presence of aphids.
 Remedies.-For the control of aphids on cabbage, the best
 remedy is to spray the plants with a solution of tobacco ex-
 tract. For directions for making this see melon aphis under
 watermelons, page 199. On cabbages a spreader of soap and
 flour-paste should be used as recommended in the discussion of
 cabbage worms. If the worms and the aphids are both present
 on the cabbages, the tobacco can be added to the lead arsenate
 spray, killing both pests at one time.
 Dusting the plants with tobacco dust is of some benefit, and
will often keep down the number of aphids and prevent an
outbreak, but will not control effectively an outbreak that has
gained headway. These outbreaks often start on plants scat-
tered thru a field and by pulling them up and destroying them,
a general outbreak can be forestalled or at least delayed.
 Enemies.-Aphids are a very attractive article of diet to a
large number of enemies which are usually able to hold them in
check. Only the wonderful rate of reproduction of the aphids
enables them to have a surplus with which to start a destructive
outbreak after supplying the market" of their enemies.
 The smaller birds such as wrens, fly-catchers, and warblers
destroy great numbers of aphids. A flock of young chickens,
if given the freedom of the garden, will do excellent work in
ridding it of aphids.