Florida Agricultural Experiment Station


hoppers also, which, after the caterpillars, are the most destruc-
tive insects in a velvet bean field.
 4. A careful watch should be kept for the first moths. The
farmer can distinguish this insect from any other common Flor-
ida moth by the (usually double) diagonal line which stretches
across both wings and turns up to the apex of the fore wing
(Fig. 11), the appearance of the under side of the wings, and the
peculiar darting flight. These moths may be expected during
July in South Florida, during August in Central Florida, and dur-
ing late August and early September in the extreme northern and
western sections of the State.. When the moths are noticed in
large numbers in the fields, it is probable that the beans will need
to be sprayed or dusted after twelve days or two weeks. The
presence of moths should, therefore, be a signal to the farmer to
obtain spraying materials.

 CONTROL BY SPRAYING AND DUSTING
 The application of lead arsenate or zinc arsenite is the best
means known for controlling the caterpillar. It will be well to ob-
tain these in the powdered form, because the powder is more uni-
form in composition than the paste, especially when the paste has
lost some of its water. Paris green should not be used on velvet
beans, as they are easily burned. A dosage of paris green strong
enough to kill a large percentage of the caterpillars is sure to
severely damage the vines. Even with the dosage of lead arse-
nate recommended here, the leaves will be burned sometimes.
However, this burning will be confined to old leaves that have
almost fulfilled their mission, and no serious damEge will result.
Contrary to the general rule the young foliage of velvet beans
is less easily burned than the old. A young and vigorous leaf
is evidently more able to withstand the poison.
 Owing to the late appearance of the caterpillar and the al-
most sure development of "cholera," there is usually not more
than a month during which the grower will need to protect his
crop. It is not always necessary to treat the entire field. If the
most severely infested portion is treated, the birds will congre-
gate on the untreated portion and often hold the caterpillars in
check there.
 The total cost of spraying at the Station in September, 1915,
was $1.10 an acre, while dusting at the same time and place cost
80 cents an acre for one application. It has never been necessary
to repeat the spray. At least two careful dustings are required