No. XL. 



Printed for the Ceylon Agricultural Society 



THE RICE-BUG OR PADDY FLY. 



The rice-bug is the same insect that in Ceylon is known as the paddy fly, and causes great damage 

 to local crops. Indeed, the necessity for rigid observance of seasons in padd_y cultivation is chiefly 

 due to the attack of fly which an out-of-season crop is invariably subjected to. An Indian report 

 (by Mr. H. Maxwell-Lefroy, the Imperial Entomologist) contains a very full account of the pest, its 

 distribution, habits, and life history, as well as the method of combating it ; and the information given 

 below is mainly abstracted from that report. 



The scientific name of the rice-bug is Leptocorisa varicornis, and the genus is believed to include 

 three species ; but the points of distinction are very slight, and probably do not imply any difference in 

 life history. The bug is commonly found in long grass and thick vegetation, being present here singly. 

 It is only at special times and on special crops such as paddy, that it occurs gregariously. The morning 

 and evening are its most active periods, and during the hot part of the day it goes deep into shelter. As 

 all who are familiar witli the insect know, it is coloured green, and associated with an objectionable odour, 

 being hence sometimes called the " Green bug." Its normal food is the sap of flowering shoots of grasses. 

 When infesting paddy, it feeds on the tender developing grain, which is full of milky sap. The dark 

 brown eggs are laid on leaves in clusters or rows, and number from twenty- four to thirty. They are 

 protected by a gummy substance, which helps to attach them to leaves and prevents their being washed 

 away by rain. The eggs take from six to eight days to hatch out. Between hatching and maturity the 

 nymph passes through five stages, occupying, say, about eighteen days, during which time the wings 

 are gradually developed. It is not exactly known how long the imago, or fully developed insect, fives, 

 but insects have been kept alive in captivation for three months. The following is an actual record : 

 Eggs hatched on September adults reared on 18th, and lived until November 1. Of enemies to the 

 rice-bug, there are two known : Cicindela sexpuncta, Lin, which is abundant in rice fields in India from 

 August to October. This is a flying insect and destroys the rice-bug in numbers. Another is an egg 

 parasite, which has not been described as yet. Ordinarily, the bug occupies a life cycle of from four 

 to five weeks in warm weather, breeds freely with the rains, and feeds on rice, dry grain, and grass. 

 There are apparently five bloods, depending, however, on local conditions, food supply, &c. With 

 cool weather the insect leaves the open field and goes into the denser shelter of uncultivated land. 

 There is nothing to show that it breeds again till the following rains. 



We now come to the most practical part of. the circular, namely, that referring to treatment. 

 (1) There is the treatment resting upon superstition, and consisting of " mantras "- or charms. This 

 may be put down as utterly useless. (2) Smoking by burning aromatic herbs and resinous substances 

 to windward. This is only a temporary remedy and, though useful in saving individual fields, merely 

 shifts the enemy. (3) Ropes saturated with resin or kerosine or fish od are drawn over the fields so as 

 to brush against the ears of paddy. This is rather more effectual than the last. (4) A paddy winnow 

 smeared over with some glutinous substance like birdlime (e.g., jak milk) is tied to a long pole and passed 

 over the heads of paddy, so that the insects are caught in large numbers on the sticky substance on the 

 winnow. The process has to be repeated over and over again. It is tedious, but simple and effective. 

 (5) An elongated cloth bag is run across the field sweeping in the bugs as they rise. The bag is either 

 soaked in crude oil emulsion (1 pint emulsion to 2 gallons water) or the inside smeared with something 

 9(4)09 



