INSECTS INJURIOUS TO AGRICULTURE IN JAPAN 53 



also, particularly in the paddy fields, whereas the last two attack the 

 roots in dry fields only. 



The tipulid Tipula parva (95, 154) is found most commonly in 

 Japan attacking rice, wheat, and barley, but is not a major pest. 

 There are two broods a year, and the winter is passed in the larval 

 stage. These larvae pupate in the spring and emerge as adults early 

 in June. Those of the second brood appear the middle of August. 

 According to Onuki (154) the first brood appears in April and the 

 second in September. The greatest injury occurs in the seed bed. 

 The larvae prefer a clay soil which is wet and shaded, and they feed 

 upon the roots at night. Collection of adults by net is recommended 

 as a means of control. Another species (T. praepotens) is of similar 

 habit. 



A species of thrips, Phloeothrips oryzae (96), is common upon rice 

 and wheat in northern Japan, particularly in Nagano Prefecture, 

 and when they are abundant the effect is to retard the growth of the 

 plant and to give a yellowish or whitish appearance to the leaves 

 and head. The first generation in June feeds upon the foliage, 

 whereas the second, in August, attacks the blossoms. The winter is 

 passed in the adult stage in sheltered places. 



In Hokkaido a trichopteron of the family Leptoceridae (1), since 

 determined as Setodes iris, attacks the roots and basal portions of the 

 rice stalk and at times causes damage. There is a single brood each 

 year, and the winter is passed in the nymphal stage in the stubble of 

 rice and other plants in the field. 



INSECTS ATTACKING WHEAT, BARLEY, RYE, AND OATS 



The major pests of the cereal crops in Japan and Chosen are 

 Euxoa segetis, Sesamia infer ens (Leucania innoeens But!., S. nona- 

 grioides var. albieiliata SnelL), Cirphis unipuncta, Sitotroga cereal- 

 ella, Locusta (Patchy tylus) migratoria var. danicus, Aenaria scotti, 

 Cicadula fasciifrons, Nephotettix apicalis var. cincticeps, and Phloeo- 

 thrips oryzae. Most of these species have been discussed as pests of 

 other crops. 



Of the species of lesser importance there may be mentioned Ghae- 

 tocnema cylindrica, G. japonicum, Grepidodera japonica, Tipula 

 parva, and Lygus lueorum. 



The well known Angumois grain moth, Sitotroga cerealella (96, 

 186) , is widely distributed in Japan and Taiwan and does consider- 

 able damage. It oviposits quite generally in the field, and attacks 

 corn and rice as well. Two broods are produced each year, and hiber- 

 nation is in the larval stage in the grain. 



The elaterid Agriotes sericeus (96) causes some damage to small 

 grains in the main islands by the feeding of the larvae at the roots. 

 It is also recorded as attacking corn and various other field crops. 

 Each generation covers a period of four or five years, and the adults 

 appear each year in May. The only control suggested is the collec- 

 tion of adults as soon after emergence as possible. 



SUGARCANE INSECTS 



The growing of sugarcane in Taiwan has attained large pro- 

 portions in relatively recent years in an effort to offset the high 

 cost of imported sugar, and large plantations are found in the 



