526 
THE TROPICAL AGRICULTURIST. [Feb. 1, 1899. 
history of the deBtruclion of the dreaded cottony 
cushion scale by the imported ladybird beetle, but 
quite unprepared to find how important that inciJeut 
had been, or how far the principle of fighting insect 
pests by the introduction of their natural enemies 
had been turned to practical account. The magni- ' 
tude of the interests which were seriously threatened 
by the spread of insect pests under the peculiarly 
favourable conditions of the Californian climate are 
well known. The pressure of these large interests 
operating upon the peculiarly free and open naind 
of the Californian have brought about results of 
the most surprising kind— results full of information 
and suggestion to scientists throughout the world, 
and especially important to the inhabitants of 
Australia. 
Beetle v. Scale. 
"Let us spray" is no longer the watch-woril of 
the Californian fruit grower. " Start an Australian 
colony" is a much more up-to-date proposition. The 
■pray, or more frequently fumigation, is used in the 
case of diseases for which no effective natural enemy 
has yet been found, but the greatest good has 
been done by "our little Australian friends," and 
the great aim of the fruit grower is to diHcover the 
natural enemies of the remaining pests. The results 
of the discoveries already made, and the va^it benefits 
accruing, have been to elevate entomology to the 
first rank of importance. It is no longer looked upon 
as merely the amiable pursuit of sticking pins 
through harmless beetles, and finding hard names 
for the most simple insects, but the science has be- 
come a subject of the highest practical value. "It 
has saved the State millions of dollars," and in 
America, especially, where the value of anything 
can be stated in dollars, its position is secure. 
The first triumph was the discovery of the Australian 
benefactor, Vedalia cardinalis, the enemy of the 
cettony cushion scale, Icerya purchasi. The citrus 
fruits of California are valued at £1,250,000 sterling 
per annum, with a rapid expansion of production 
as the result of an increasing area of plantation. Some 
years ago, when the Australian scale got to work on the 
trees, ttie industry was confronted with apparently 
total extinction. The scale had killed out the orange 
trees at the Cape, and in spite of remedies, it was 
found that the disease made rapid progress in 
California. The Scale could be held only partly in 
check by treatment, and the expense was too great. 
It was at this crisis that Australia, which sent th* 
hane, produced the antidote, and this valuable and 
growing industry was saved. The ladybird beetle, 
when introduced, commenced on the scales, and 
finding plenty of food ready to hand, and being 
free from their own parasites, which they had left 
at home, devoured the pests, and soon began to 
die owing to the scarcity of scale food. Thus the 
most dreaded of all diseases of the orange has now 
ceased to give any serious trouble in California. 
There is, in fact, far more anxiety to preserve 
Bufficient scales to keep the Australian beetle from 
dying out than that the pest will otherwise give 
trouble. Many growers are cultivating scale to feed 
their ladybirds, but Mr. Craw assures them that 
they need not do so, as he is keeping sufficient stock 
to supply all the requirements of the State. It 
seems strange enough that those simple looking 
glass jars in Mr. Craw's office contain that which 
is capable of ensuring the great citrus industry of 
California against such a destructive pest as the 
deadly scale. It is true, however, and what is more, 
the vessels contain many other beneficial insects 
destined to play havoc -with pests almost as des- 
tructive to other fruits, as the cottony cushion scale 
jB to citrus trees. 
The Koebele Discoveeies, 
The science of entomology in California has been 
stiinulated, and in a measure directed, by practical 
sug<'estion. The Californian fruit grower has no 
use°for "scieutitio information" which cannot be 
turned to practical account, When the orange 
industry waa ia its peateat strength, eaWWlog^^'^ 
came out from Washington to recommend and 
direct the ose of certain remedies which had been 
beneficial in other States; but the leading growers 
said, "Don't waste your time in that way. We 
know all about your sprays and washes, but they 
are not good to ui. You can't kill all the insecti*, 
and in this country what are left are enough to 
keep U9 spraying all the time, and the thing won't 
pay. We want yoa to hunt up the natural enemy 
of the scale." It waf. a fortunate thing for California 
when the President appointed the late Mr. F. M. 
Coppin, of San Francisco, as American commisBioner 
to our Centennial Exhibition. Efforts to get the 
Government to send a scientist to Australia ia 
Bcarch of the natural enemy [of the orange scale 
had failed, and might not have succeeded to this 
day. But Mr. M. Coppin aaid to a larj^e fruit 
grower, " We'l, I'm going out lo Australia. Can I 
do anything for your interest?" The reply wis, 
" There is only one thing to be done. Take a scientific 
man alone with you, and let him find something 
that will cure the orange scale." Mr. M. Coppin 
knew this was good advice, and he acted upon it. 
paying the cost of the scientific expedition out of 
the exhibition appropriation. The selection of a 
scientist for the work was a most happy one — viz., 
Mr. A. Koebele. a young entomologist of the United 
States Department of Agriculture, who had been 
working for some time in California. How Mr. 
Koebele discovered the Vedalia cardinalis, and saved 
the Californian lemon industry is well known. The 
work was belter appreciated in California than at 
Washington, so that when afterwards Mr. Koebele 
was wanted to go out again, and also to visit India, 
China, Japan, and the Facific Islandi to look for 
the enemies of the other pests, no encouragement 
was received from the Federal Department. Cali- 
fornia, however, knew the value of work of this 
kind, and the State Legislature voted £1000 for 
Mr. Koebele's second mission. The second journey 
brought great gain to the movement in favour of 
natural remedies for insect pests. The black scale 
of the citrus and olive trees, the mealy bugs and 
other pests had effective natural enemies, which Mr. 
Koebele discovered and sent home, thus completing 
the transformation which has taken place ii the 
treatment of insect pests in California. 
The Second Koebele Expbdiiion. 
Three beneficial insects, which have proved them- 
selves admirably effective, as well as several other 
promising ones still on their trial, are the result 
of Mr. Koebele's second mission. One of the most 
important is an Australian beetle, Rbizobius cen- 
tralis, which preys upon the dirty black scale of 
the olive and orange Tecomium Olex. Mr. Ell wood 
Cooper, the great olive grower of California, had 
to pay from £600 to £1000 a year in keeping this 
scale within bounds. Soon after introducing the 
Rhizobii the trees became free from the pest, and 
he now spends nothing upon remedie?. His only 
care is to preserve the beetles. This gentleman had 
stated publicly that he has spent £20,uO0 on insect 
pests, lir. D. Freeman, a large orange grower, had 
his crop reduced from 250 tons to 350 boxes by the 
black scale, but this Australian beetle saved the 
grove and brought it back to full productiveness. 
These are only examples of the general experience. 
Another valuable acquisition is the Cryptolaemus 
montronzieri, an effective enemy of the mealy bug 
(Dactylopius), and two others introduced at the 
same time promise to be very useful. The third 
proved acquisition of this mission is an Australian 
ladybird, which works on the orange scale even 
more effectively than the original Vedalia cardi- 
nalis — viz., the Novins Koebelei. These, with certain 
other beneficial insects, introduced in some places 
accidentally, have brought about the great change 
in the treatment of pests which has been already 
referred to. Scores of colonies of the beneficial 
insects are sent out in little boxes from Mr. Craw's 
office every mouth, and before the pests were so 
well under control as they are now the colooi^f 
sent oat ranged from 300 to 800 per mouth. 
