235 



Station. Doubts have been expressed as to the efficacy of these 

 lanterns, because it frequently happens that male moths or females 

 that have already oviposited are the only ones trapped by this means. 

 In another case various injurious insects were only attracted to the 

 field, but not killed by the lantern, while many beneficial ones were 

 destroyed in it. Other measures are collection of the egg-clusters, 

 removal of the outer and more vigorous shoots in which larvae tend 

 to collect, and gathering the floating leaves which often enclose the 

 larvae. Cutting of? the infested stalks early in July is very effective 

 in exterminating the first brood larvae. Submerging the rice stubbles 

 is also effective, if care be taken to prevent the escape of floating 

 larvae. Removal of the stalks on which the leaf-sheath has changed 

 colour is the best measure against the second brood larvae. This 

 should be done from the end of August till the end of September. 

 Special treatment of the rice straw is of importance ; as this is utilised 

 for various purposes, total destruction is impossible. It should either 

 be tightly heaped in order to prevent the emergence of moths from 

 the larvae that are enclosed in it, or it should be closely covered with 

 mats or similar material so as to prevent the escape of the adults. 

 Soaking the straw in hot water or fumigation with carbon bisul23hide 

 may in certain cases be practicable. Raking over the heaps of straw 

 in the spring, when the hibernated larvae are emigrating, is also 

 considered an effective measure. Burying or burning the stubble 

 and removal of weeds around rice fields may also be of some value. 



The second part of this report deals ^nth Schoenobius incerteUus, 

 Wlk., of which all the stages are described in detail. This moth 

 usually appears three times a year, though in certain places there are 

 only two generations. The larva passes the winter within the rice 

 stubble and pupation takes place in April or j\Iay of the following 

 year, the moths of the first brood appearing shortly afterwards. 

 These oviposit on the rice-leaves near the tip. The larvae hatched 

 from these eggs bore into the stalk and pupate in July, and those of 

 the next generation in the latter part of August. The moths derived 

 from these give rise to the hibernating larvae. 



In habits S. incerteUus differs from C. simplex mainly in the follo^\^ng 

 points. In S. incerteUus the egg-cluster is covered with hairs from 

 the body of the parent, while in C. simplex it is naked. In the case 

 of S. incerteUus the eggs are always laid at the tips of the leaves, 

 while in C simplex they are laid in the leaf-sheath in the case of the 

 second generation. In the former species the larvae that hatch from 

 the egg-cluster bore one into each rice-stalk, whereas in the latter 

 sjjecies they all collect in a single stalk ; so that in the former case 

 the injury is widespread, while in the latter it is more concentrated. 

 In the case of S. incerteUus each rice-stalk being only moderately 

 injured, it continues to stand in the field mthout losing its original 

 green colour : while injury by C. simplex causes the stalk to become 

 bleached and usually to break do^vn. As the larva of S. incerteUus 

 bores directly into the rice stalk, without affecting the leaf-sheath, 

 the changed colour of the latter, so characteristic of infestation by 

 C. simplex, is never seen. The larvae of the last brood of C. incerteUus 

 pass the winter mainly "^dthin the stump of the plant, while those 

 of C. simplex do so chiefly in the cut-off stems and only occasionally 

 in the stump. 



