56 CIRCULAR 16 8, 17. S. DEPARTMENT OP AGRICULTURE 



in the United States. The more injurious insects attacking it are 

 the noctuids Barathra brassicae, Chloridea dipsacea. Eirxoa segetis, 

 and Sesamia inferens, and the European corn borer. Pyrausta 

 nubilalis. Most of these have been dealt with as pests of other 

 crops of greater importance. 



Among the species of lesser consequence attacking corn are Am- 

 sacta lactinea and Sitotroga cerealella in Japan and Taiwan, and 

 Thalla^odes quadraria in Taiwan. Zinclcenia fascialis. an account 

 of which is given among the sugar-beet insects, is of general distri- 

 bution in the East. Phassus excrescens. which bores into the stalk, 

 Luperodes discrepans. and Agriotes sericeus infest corn in Japan, 

 and the aphids Aphis formosanus* A. maidis. and Rhopalosiphum 

 avenue attack corn in Japan and the first two in Taiwan as well. 



The well-known European corn borer Pyrausta nubilalis (1^9) is 

 of general distribution throughout Japan and Chosen and is com- 

 monly found in China and Siberia. In Japan this species was for- 

 merly considered primarily as a pest of millet and various beans, 

 but in recent years more attention has been paid to it as a pest of 

 corn. In Hokkaido and also in Chosen, there is a single brood a 

 year, the adults appearing in August. Matsumura (95, 96) reports 

 two broods in Hokkaido and three at the latitude of Tokyo. In Hok- 

 kaido the two broods of adults are said to emerge the middle of 

 June and August, respectively, whereas the three at Tokyo appear 

 in May and June, July and August, and August and September, 

 respectively. In Hokkaido the winter is passed in the larval stage 

 in the bamboo poles used for supporting the bean stalks, and in the 

 case of millet in the stubble in the field. The larva bores into the 

 stalk of millet near the base, causing it to break under the weight 

 of the developing head of grain. Three parasites are recorded as 

 attacking this insect, all apparently endemic in Japan, namely, the 

 tachinid Exorista tritaeniata Bond., and the ichneumonids Pimpla 

 pyraustae Mats., and Eugnomus pyraustae Mats. 



MILLET INSECTS 



The major pests of millet in Japan and Chosen are the noctuids 

 Cirphis unipuncta and Sesamia infer ens. which have a general dis- 

 tribution, the European corn borer (Pyrausta nubilalis) , and Lo- 

 cust a (Pachytylus) migratoria var. d amicus. Others of lesser im- 

 portance are Agriotes sericeus, Holotrichia diomphalia. Serica simiJis 

 (Chosen only), Monochirus (Hispa) eallieanthus, Eurydema 

 rugosum. Delphax (Liburnia) furcifera, Diostrombus politus. and 

 Rhopalosiphum avenae. 



In Chosen the army worm, Cirphis unipuncta (8). is a serious pest 

 of millet and attacks" also oats, rice, barley, and Panicum frumento- 

 sum Roxb. This species is of general distribution throughout the 

 areas under consideration. There are two broods each year, the 

 adults of the first appearing the last of June and those of the second 

 late in July. The winter is passed in the pupal stage in the soil. 

 The eggs, which are laid in rows of from 20 to 30 on the leaves, 

 hatch in 4 or 5 days. The larval stage of each generation covers 

 about 25 days and the pupal stage of the first 10 days. At times 

 very extended damage occurs through the feeding of the larvae upon 



