THE BEAN BEETLE IN ESSEX.
49
Nat. Hist." xiii., 207) that "Mr. Marshall is said to have observed in
a barn in Kent a quantity of peas infested with this beetle, which had
destroyed nearly half the crop." Curtis says ("Farm Insects," page
361) that "Mr. C. Parsons [of Southchurch in this county] trans-
mitted to me some horse beans in the beginning of August, 1842,
which were entirely destroyed by Bruchi"
The economy of Bruchus rufimanus is well-known, but this know-
ledge does not readily point to any practical remedy against attack.
The female beetle hibernates in almost any shelter, and awaits her
opportunity of laying her eggs in the incipient bean-pods. The
larva that is produced immediately burrows into the young bean, and
there continues to feed until the maturity of the seed, when it is
mostly full-fed, and as the bean ripens and hardens, the grub pupates
within the chamber it has excavated for itself, and is thus secure
from all interference until the perfect beetle is produced. The final
change into the perfect beetle takes place in early autumn, and the
insect often remains for a considerable time in the bean in which the
grub has fed. It removes the testa of the bean which formed the
roof of its house, and which has been previously almost gnawn through
by the larva, but emerges no further, and is well protected in the
stack or in the granary. The beetles remain very sluggish until the
hot weather comes. They then pair, and the females begin a new
campaign of egg-laying as soon as the beans are in flower. The Bean
Bruchus is doubtless a hot summer pest. Curtis wrote long ago :—
"From the comparatively cold temperature of England, I expect our
climate will not suit it, and therefore nothing need be apprehended
by our agriculturists from its operations." This latter opinion has
not been justified, for there is certainly now an idea prevalent that
"bug-eaten" beans and peas are more common than formerly.
Chremylus rubiginosus, Ns., Sigalphus pallidipes, Ns., and a
Pteromalus are common hymenopterous parasites of Bruchus
rufimanus.
As to method of checking the pest all the advice I can give is that
farmers should act upon the old saw, "Prevention is better than
cure." Doubtless the parent beetles are perfectly happy in the
ground when the affected seed in which they are ensconced is sown,
but the presence of the Bruchus in the bean is generally to be known
either by a small opaque spot which covers the orifice of the larval
chamber, or by a spot resembling a small black pin's head which
marks the place of entrance of the young larva into the immature