192 
terous insects which bore in the stem, Chilo simplex Buth, 
and Schaenobius bipuntifer \\^alk. The former is double 
brooded, and many larvae will be found in a stem ; the latter 
produces three broods a year, and the larvae will be found 
singly. It would seem that the danger of introducing these 
pests lies in the importation of rice straw used for packing. 
Fortunately they are parasitized in several stages. The 
most efficient natural enemy is the egg. parasite, Tricho- 
gramma japonicus Ashm. Were it not for this and other 
parasites the losses from the borers alone would be very 
great; but even as it is, the writer is informed that in the 
worst infested regions fully fifty per cent, of the crop is some- 
times lost. The borers are also controlled to some extent 
by burning infested plants when discovered. Such plants 
are easily distinguished by their pale color at or near ma- 
turity. After the crop is harvested the stubble must also be 
burned, as the insects pupate in or near the ground. 
Other insect pests to which my attention was called were 
the leaf-hoppers — Delphax furcifer and D. strictella — which 
suck the plant juices; the rice weevil, Calandra oryzae, a 
Noctuid moth, Xonagria inferens ; a butterfly, Pamphila 
guttata; and an aphid, Schizoneura sp. Two other leaf- 
hoppers, Scotinaphora vermiculata and Selenophalus cincti- 
ceps, also affect rice, and the latter is supposed to be the 
means by which one of the fungus diseases is transmitted. 
The following are some of the plant diseases affecting rice 
in Japan: 1. Stigomonose or dwarf disease (Japanese 
Oshiku-byo). This disease is supposed to be due to punc- 
tures made by the leaf-hopper, Selenophalus cincticeps. At 
certain seasons this insect is present in excessive numbers in 
the rice fields. As a measure of control, a thin layer of petro- 
leum is spread over the flood water, and the insects are 
brushed into it and destroyed. To avoid injuring the rice, the 
oil is drained off immediately. 2. Brusone ( Japanese Mochi- 
byo.). A fungus disease causing spotting of the leaves. Often 
very destructive. The fungus is one of the Mucedinaceae, 
Dactylaria parasitans Cav. Remedial treatment consists of 
thorough tillage and the avoidance of excessive nitrogenous 
manuring. 3. Leaf-blight (Japanese Hagare-byo.'). Causes 
considerable damage to the crop in some years. The fungus 
is one of the Helminthosporieae, Helminthosporium oryzae 
IMiyabe and Hori. The remedial measures are the same as 
those for brusone. 4. White leaf-blight (Japanese Shiro 
Hagaro-byo.). Probably the most destructive disease of rice 
in Japan. The losses from it in a single prefecture have 
amounted to one million yen a year. The Japanese Govern- 
ment last year appropriated 3,000 yen for its study, and some 
promising results have been obtained from these investiga- 
tions. It was found that the disease is always associated with 
an acid condition of the soil. A bacterium has recently been 
