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INSECT ENEMIES. 
The leafhopper is generally distributed throughout the south-western parts 
of the United States. It has always been supposed to be a native of this part 
of North America. Recently a trip by Boncquet to Argentina revealed the 
presence of Eutettix tenella and the curly-leaf disease in the beet fields of that 
country, so the origin of the insect remains obscure. 
Losses from the ravages of the curly-leaf disease have been enormous, not 
only in California, but also in the other western States where the sugar beet 
is grown. Of course, the amount of damage will vary from year to year. - In 
the year 1914 the loss reported by one sugar company alone in California, and 
in a single small valley, was given as 1,000,000 dollars. The total loss from 
all beet-growing sections will go far into the millions. In some parts of 
California the disease is so bad that the growing of sugar beets has been 
practically discontinued, and sugar factories abandoned. 
CONTROL MEASURES. 
Experimental work in the control of the beet leafhopper has been carried 
on by the United States Bureau of Entomology, the Utal Experiment Station, 
the University of California, and the various sugar companies, but no successful 
measure has been developed whereby the leafhopper can be checked. The early 
planting of sugar beets so that the beets are well started before the leafhoppers 
appear in the fields gives the best results. Spraying the beets with various 
washes such as blackleaf—40, kerosene emulsion and soap solutions has been 
tried. Difficulty in destroying the adults with a spray, and the fact that the 
undersides of the beet leaves cannot be thoroughly sprayed make this method 
of control of doubtful value. A variety of resistant beets has not yet been 
developed. The destruction of native weeds on which the leafhopper may breed 
surrounding beet fields is practically impossible in many cases. - 
Because of our inability to control the beet leafhopper by artificial means, 
the possibility of controlling it by the introduction of natural enemies was 
given the attention of the State Commissioner of Horticulture. Later, in 1916, 
through the co-operation of the:Spreckels Sugar Company, the State Com- 
‘missioner arranged to send a collector to foreign countries to investigate 
parasites of leafhoppers with a view-to introducing them in the best fields of 
this State as an aid in the control of this pest. It was thought advisable to 
explore Australia first, as’ many species of leafhoppers are present in that 
country which are known, through the researches of Koebele and Perkins, to 
be attacked by numbers of natural enemies. Also Australia presents in its 
flora many species of Chenopodiacew, to which family the sugar beet also 
belongs. ‘The writer was selected to conduct the investigations, and left San 
Francisco in January, 1917, for Sydney, Australia, arriving there on 22nd 
February. : 
The introduction of a Dryinid parasite of a leafhopper abundant on Eragrostis - 
villosa, in eastern New South Wales, occupied much of the time of the writer 
during his first trip. A number of Wardian cases, filled with parasitized leaf- 
hoppers of this species, was sent on several steamers to the Insectary Division 
at Sacramento, but only one female Dryinid came through in a living condition. 
This was placed in a case with beet leafhoppers, and was observed to oviposit in 
them, but unfortunately no parasites were reared. The parasitism by this 
Dryinid on the above leafhopper in New South Wales was approximately 
7 per cent. In Victoria, investigation of saltbushes for leafhoppers was started, 
and near Sunshine, Victoria, the writer found a small leafhopper, abundant‘ 
on a low-growing saltbush (Atriplex muelleri.) This leafhopper was parasitized 
to the extent of 85 to 90 per cent. by two egg-parasites, Ptergogramma acuminata 
and a Mymarid. Stems of the Atriplex containing the parasite eggs of this 
insect were sent in cold storage on the Oceanic steamers to California, and 
from these a number of egg-parasites of both species were obtained. These 
were placed on the eggs of Eutettix tenella and were seen to oviposit. As 
Ptergogramma acuminata attacks several species of Jassids, the chances for 
its breeding successfully on the beet leafhopper were thought to be good. 
Winter stopped the work of collecting the egg-parasites in Australia, and the 
writer left for home on 15th June with the intention of returning on the approach 
of summer to continue the shipment of egg-parasites, provided: additional: funds 
were secured for.the.carrying.oniof ithe work,.) 0 (6) 62050) ) ie Sey 
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