Evening star. [volume] (Washington, D.C.) 1854-1972, 1929-04-20
THE MEXICAN
BEAN BEETLE

A very serious situation now faces
the local growers of garden beans of all
types, bush, pole and lima. The Mex
lean bean beetle is here and last year
fully demonstrated its ability to destroy
this crop. Without doubt the home
gardener must spray or dust If he ex-
poets to grow beans. Farmers Bulle-
tin No. 1407, published by the United
States Department of Agriculture, de-
scribes the insect and its work and sug-
gests means of overcoming Its ravages
AS illustrated in one of the accompany
ing pictures, the bean beetle occurs In
two forms, the adult beetle, well marked
by eight black spots on each wing cover,
and the larva, orange colored and COW
cred with long-branched spines. Both
adult and young feed voraciouSly on
all kinds of beans and to a lesser eX-
tent on many other plants, such as cow
peas, soy beans, alfalfa and sweet
clover. All parts of the bean plant
above ground are attacked, so that In
bad infeStationS the plants may be
completely destroyed. Both adults and
larvae feed first on the lower surface OF
the leaves, eating out narrow sections
and leaving a peculiar network which
Is very characteristic and unlike the
work of most other insects.
Control, of course, is uppermost in
the mind of the gardener. Fortunately
successful means of control have been
developed, but where the great diff
Guilty comes is in the vast numbers OF
the beetle. One crop of insects may be
destroyed only to be followed by sue
cessive waves of attack. Another diff
Guilty in control Is the habit Of eating
from the underside of the leaf, which
means that the spray or dust must be
deposited on the lower leaf surface
In spraying this is accomplished by the
use of an upturned nozzle. With
busting, there Is naturally more dis
persion in all directions, yet the bulle-
tin suggests the need Of reaching the
underside of the leaves. Spraying Is
conceded more effective than busting
but is more difficult. Magnesium
arsenate, ounce in gallons OF water
is recommended as a spray. Magnesium
arsenate has proved less injurious to the
foliage than have other arSenateS. Lead
arsenate, for example. was found sc
harmful as to be avoided under any
condition. Magnesium arsenate diluted
! with hydrated lime, one part to three
in heavy infeStations and one to five
parts of lime in light attacks, is recon-
| mended as dust.
These arsenicals are poisonous, an6
beans so treated should be thoroughly
rinsed in clean water before using. With
shell beans, where the pod is discarded
washing is, of course, not necessary
A pyrethrum oil soap, sold under q
trade name, has been found real
success, but is somewhat more costly
1t has, however, the advantage of leav.
ing no poisonous residue on the beans
Just what the outcome of the home
| gardeners battle with the Mexican
bean beetle is to be is debatable ques-
ton. 1t would be almost death blow
| to the vegetable garden to lose the
bean crop. With diligent spraying anC
| burying of bean plants as soon as the
crop is harvested there Is an optimistic
outlook One of the strange facts
about the Mexican bean beetle is thai
it is one of the ladybirds, family Of
usually highly beneficial insects be-
cause of their predatory habits or
scales and other harmful insects.