34 
WORK OF BOARD OF AGRICULTURE AND FORESTRY. 
[From the Report of the Governor of Hawaii for the Year 
1906-07.] 
ENTOMOLOGICAL WORK. 
A marked result of organized entomologcial work has been 
the introduction, propagation, and distribution of beneficial 
insects, carried on by the joint effort and expense of the Ha- 
waiian Sugar Planters' Association and the Territorial board 
of agriculture and forestry. 
Until within the past few years, plants, trees, fruit, and seeds 
from all parts of the world, accompanied by their insect pests 
and diseases, came into Hawaii without objection or hindrance, 
either by inspection or fumigation, with the result that all the 
pests now infesting crops, wild growth, and forest trees were 
introduced into a country that was congenial to their propaga- 
tion and spread. The same country that has favored the 
destructive pests has also been favorable for the increase of 
the beneficial species that have been introduced to prey upon 
the pests. 
It is a well known fact that such insects as live on other 
species seldom attack any vegetable growth of fruit, no matter 
how hungry they may be. The beneficial effects of the intro- 
duction, nearly three years ago, of insects that live on para- 
sites, have surpassed the most sanguine expectations. In three 
years the loss to the sugar planters of this Territory from the 
"cane leaf hopper" ( Pcrkinsiclla saccharkida) has been reduced 
from $3,000,000 to practically nil, and plantations that were to 
a certain extent abandoned are again producing heavy crops 
of sugar, because the parasites have checked the leaf hoppers 
by destroying the eggs of that pest. This never could have 
been accomplished by artificial remedies. 
Not only has the cane leaf hopper been subdued in the sugar- 
cane plantations, but the "buffalo leaf hopper," which was such 
a destructive pest upon coffee and other economic trees, has 
been greatly checked in numbers. To show that this method 
of warfare is not confined entirely to insects inhabiting trees 
and plants, I have but to call your attention to the evident 
good work of a very minute imported hymenopterous parasite 
(Eucoila impaticns) that is doing good work in reducing the 
numbers of the stock pest called the "horn fly." This parasite 
has been widely distributed on the islands. The two pre- 
, viously mentioned species attack the eggs of the pests, whereas 
the "horn fly" enemy attacks the maggots and pupae in the 
cow dung. Besides distributing colonies of these parasites in 
pastures infested with "horn fly," we also breed them and other 
