The Hawaiian star. [volume] (Honolulu [Oahu]) 1893-1912, 1906-02-13
THE ALLIGATOR
PEAR TREE BLIGHT
A BULLETIN CONCERNING IT AND
THE TREATMENT TO BE GIVEN
HAS BEEN ISSUED.

The following are the chief features
of a bulletin lately issued by the Ex-
pertinent Station treating of the blight
that affects the alligator pear trees.
The enemy of the Avocado or ALI
gator pear (Persea gratissima)S COM
monty known in and about Honolulu
as the blight of the Alligator pear"
or simply as pear blight" is proper
ly speaking, not a blight at all but an
insect, one of the mealy- bugs, Pseudo
coccus nipae Mask, belonging to the
same family, Coccidae, as do scale-in-
sects. This family is related to the
plant-lice and leaf-hoppers of the order
Hemiptera. blight" is a term in COM
mon use by botanists, or rather plant
Psychologists, to designate certain fun
gus diseases of plants, these fungi be-
ing low parasitic forms of plant life.
Besides the great injury and disfigure-
ment caused by this mealy-bug to the
foliage fruit and leaf buds, and ter
minal branches of the Avocado, the
pest infests the fig, grape guava and
breadfruit.
The Avocado mealy-bug and it's re-
rated forms, including the scale-insects,
represent the most injurious family of
insects with which the horticulturist In
a tropical country has to contend. The
short life-cycle and immense increase
in succeeding generations render them
capable of appearing in enormous
numbers on their respective food
plants within a very limited space OF
time and, in many instances, before
their presence is detected by the own
ers of the trees or plants. The ability
to recognize these insidious foes be-
fore serious injury is accomplished will
enable the grower to check the increase
before the pests become epidemic.
In general the lfe-history of the
members of the family Coccidae is as
follows The young with few excep-
lions, are Matched from minute eggs.
1t is during the egg state, particularly,
that these serious plant pests have
been transported long distances, maxi
ing the distribution of many species
almost worldwide. The young pos
sesses legs, a distinct head and their
mouth-parts are formed for sucking.
Soon after Matching, they dispense over
the plant to feed. This they do by in
sorting their beak-like mouth or pro-
boscis into the tissues and sucking
from the plant it's sap. The result of
myriads of individuals engaged in this
operation can be imagined to have a
very disastrous effect on the health
and even the very life of the infested
A.
development take place, these small
insects cast off their skins to provide
for the increase in size. During the
development period the males are not
unlike the females in appearance.
When full-grOwn the females remain
stationary or practically so, having UNI
dergone an incomplete metamohphosis.
All the female Coccidae are either
partly or entirely covered by a wax
like, scaly, powdery, or cottony excre-
ton and also in some instances further
enveloped in the adult stages by the
addition to such excretion of the cast
skins of the younger stages. The waxy
covering of the female insect affords a
place of protection to the eggs and
newly Matched young and offers more
or less resistance to the action of the
various insecticides in use to destroy
them. In some instances the cover
ing is scale-like, in others cotton or
meal-like. Thus we have the common
names, as for example, scale-insect,
mealy-bug and cottony cushion-scale.
The conspicuous part of the Avocado
mealy-bug is its white meal-like COW
erng. The color of the body is yellow
varying to orange. On slight pressure
of the body of the fully matured fe-
male exudes a bright orange fluid.
The males when fully developed form
about themselves a cocoon and after
undergoing a complete metamorphosis
issue therefrom in the adult form with
a single pair of wings. They are min
ute in size and would not be observed
by the plant grower. In fact the male
of many species are little known
scientifically.
Both sexes are active while young
end travel from tree to tree where the
limbs of an infested tree overlap the
limbs of another. They are also blown
about on leaves by the wind or car
ried by water. They are distributed in
some instances by species of ants as
ISOLATED with them; and, in the course
of commerce, are carried from one To-
cality or country to another on their
food plants or the products of the same.
The Avocado mealy-bug is first rec
orded in Hawaii by Mr.. r. C. L. Per-
kins in 1902.
Several ladybirds beetles have been
observed feeding on the Avocado mealy
bug of which one, Cryptolaemus mont
rouzieri Muls., is especially abundant.
This species is a mealy-bug feeder and
was collected by Koebele in Queens
land in the Spring of 1894 and forward
ed TO Honolulu where it was received
and liberated by Mr.. Joseph Marsden,
then Commissioner of Agriculture and
Forestry.
This ladybird beetle is one of the
most active of Koebeles introduced
beneficial insects.
It is regrettable that this mealy-bug