Plant Sanitation. 



300 



impracticable, as it would mean the almost complete defoliation of the trees. My 

 correspondent states that he has been very successful in trapping the moths by 

 means of a powerful acetylene lamp set in a large basin of water with a film of 

 kerosene. He has satisfied himself that the pregnant females are captured, as he 

 has observed them— in tlieir dying struggles- laying strings of eggs. The pest more 

 especially affects certain spots on every estate, resulting in the permanent weaken- 

 ing of the trees, some of which even succumb to repeated attacks. 



The rice-fields at Padiapalella (near Maturata) have been infested by the 

 minute caterpillar of a species of Nymphula, (probably N. fluctuosalis). The cater- 

 pillars enclose themselves in small cases composed of pieces of the rice leaves. They 

 are said to be nocturnal, hiding during the day low down amongst the stalks and 

 coming up to feed at night. The caterpillar is adapted to an aquatic existence, 

 being provided with tufts of filaments on each side which act as gills, and enable 

 it to breathe water instead of air. When it comes up to feed it carries in its case 

 a sufficient quantity of water to keep its gills wet. Wood-Mason described and 

 figured a similar larva, under the name of Paraponyx oryzalis, from Burma, where 

 it is reported to be very destructive to rice crops. From our knowledge of its 

 habits it is evident that any attempt to destroy the pest by flooding the fields 

 (as has been practised against some air-breathing caterpillars) will be useless. But 

 I have suggested the employment of the opposite process — the withdrawal of the 

 water from the fields— if it can be effected without serious injury to the plants. 

 If the insects could be cut off from any supply of water during the heat of the day, 

 I believe that their respiratory apparatus would be dried up with fatal results. 



Cultivators of Crotalaria are again complaining of the destruction of their 

 seed crop by a small larva that bores into the pods and consumes the seed. This 

 is the caterpillar of a blue butterfly (Polyommatus boeiicus). The eggs are laid 

 upon the blossoms of the plants. Powdered sulphur might be used as a deterrent 

 against the deposition of the eggs. The treatment would cost very little if applied 

 to a limited area, and would ensure a supply of seed for replanting. 



Seed heads of the castor-oil plants on the Experimental Silk Farm are 

 infested by a boring caterpillar which proves to be identical with the well-known 

 Cacao-pod borer (Dichocrocis punctiferalis, Guen). 



Large numbers of a handsome bronze-green Buprestid beetle have been 

 received from the Cotton Experiment Station, where they were found resting on 

 the cotton plants. The larvae of the Buprestidae are known to bore in the stems 

 of various trees and plants. Sphenoptera gossypii — a beetle belonging to the same 

 family is a notorious pest of the cotton plant in India. Specimens submitted to 

 Mr. Maxwell Lefroyhave been referred to a distinct species (Psiloptera fortuosa, 

 Fabr.). No signs of boring larvae have as yet been observed in our 

 cotton plants. 



While investigating an obscure disease of Dadap (Erythrina) trees, the 

 Government Mycologist observed that the soil around the roots was crowded 

 with the larvae and pupae of a spieces of Cicada. It was at first thought that 

 these insects might be the cause of the death of the trees ; but against this idea 

 is the fact that the roots themselves have a quite healthy appearance, and that 

 the trees are dying from above downwaixls. Examples of the adult cicadas have 

 since been submitted to me, and have been identified as Cryptotympana inter- 

 media, Sign. 



Swarms of young locusts (Autarches miliaris), newly emerged from the 

 eggs appeared about the middle of March in the Matale district. When first 

 hatched they cluster upon shrubs and low herbage, and are said to be independent 



