72 CIRCULAR 16 8, IT. S. DEPARTMENT OE AGRICULTURE 



The sphingid Acherontia styx (11 4) is a general pest of sweet- 

 potato as well as other vegetables throughout Japan, Chosen, and 

 Taiwan. Its distribution extends southward to the Malay Penin- 

 sula. The variety crathis is frequently found upon potato in Japan, 

 but seldom in injurious numbers. It attacks various Solanaceae and 

 Sesamum indicum as well. The adults are found from June to 

 September, and the larvae slightly later, there being only one genera- 

 tion per year. 



Another sphingid moth Theretra oldenlandiae (96) is common 

 upon sweetpotatoes in Japan, Chosen, and China, though usually 

 not causing serious injury. It also attacks the potato, beans, taro, 

 and various cruciferous plants. The life cycle extends over a period 

 of one year, and hibernation takes place in the pupal stage in the 

 soil. The adults emerge in June and July, and the eggs are de- 

 posited singly on the undersides of the leaves. The mature larvae 

 enter the soil for pupation in September. 



The gelechiid Braclunia triannueUa (95, 165) is a common pest of 

 sweetpotato in Japan, though usually not a serious one. There is 

 one, and possibly a second, brood each year, and the winter is 

 passed in the pupal stage in dead rolled leaves. 



The well-known and widely distributed sweetpotato weevil, CyJas 

 formicarius (95, 169), is a serious pest in Taiwan, Okinawa, and 

 China, but has not as yet been recorded from Japan proper. Accord- 

 ing to Fletcher this insect is the worst pest of the crop in India and 

 is endemic in that country. In Taiwan seven generations are pro- 

 duced each year, and the winter is passed in the adult stage. These 

 same habits characterize the species as recorded in other countries. 



A chrysomelid, Chrysoclius chineiisis, is found in Miye, Tokushima, 

 and Tochigi Prefectures in Japan proper as an important pest of 

 sweetpotato and taro. It occurs also in Taiwan (169) and China. 

 According to Takagi (177) there is one generation a year, the adults 

 appearing in late June and early July. The eggs are laid just below 

 the surface of the ground adjacent to the stem, and upon hatching 

 the larvae bore into the roots. The infested potatoes may be rec- 

 ognized by the dark green color of the skin about the puncture at 

 the point of entrance, by the bitter taste, and by a distinctive odor. 

 The tunnel is filled with excrement. Pupation takes place in earthen 

 cells outside the root, the duration of the pupal period being about 

 two weeks. 



According to Maki (82) the mirid bug Halticus minutus, a serious 

 pest in India, is becoming abundant in the Pescadores Islands. It 

 is a well-known pest in Japan and Taiwan also. There are several 

 generations a year, and the leaves and stalks of peanut, melon, and 

 cabbage are attacked, as well as sweetpotato. Wet seasons are par- 

 ticularly favorable to the development of the pest to the point of 

 destructiveness. 



INSECTS ATTACKING CABBAGE, RADISH, TURNIP, AND CARROT 



The well-known cabbage worm. Pieris rapae (1W), is very abun- 

 dant throughout all Japan and Chosen, extending to China, Siberia, 

 Europe, and Xorth America. It is not recorded from Taiwan. In 

 Hokkaido there are two or three generations each year. Where there 



