PLANT SANITATION. 



Entomological Notes. 



• . 



By E. Ernest Green, Government Entomologist. 



The cut ends of young Hevea stumps are frequently tunnelled by various 

 small species of bees and wasps. But these insects are not responsible for the 

 dying back. The pith of any dead stem would be utilized in a similar manner. 

 When a Hevea plant is stumped, it usually dies back to the node, and it is in 

 such dried ends that the tiny wasps construct their nests. They cannot be 

 regarded as pests, buc more properly as friends. For most of them provision 

 their nests with Aphides taken from some other plant. 



Specimens of a small Longicorn beetle, said to be responsible for the 

 death of young Hevea trees, have been received from Southern India. The in- 

 sect proves to be Pterolophia annulata, Ohevr., a species that occurs in Ceylon 

 also. I have no records of injury done by this insect to Para rubber in this 

 country, but I have bred out a specimen from the diseased bark of a 

 Ceara rubber tree. My correspondent from India reports that the beetles 

 girdle the stems ; the upper parts of the trees 

 dying back down to the injured area. This 

 girdling habit is common to many species of 

 Longicorn beetles. The object of the manoeuvre is 

 believed to be to check the sap and induce the 

 degree of decay best suited to the nourishment 

 of the grubs of the beetle ; the eggs ha ving first 

 been inserted in the bark above the point of injury. 

 If this pest should become common, it might cause 

 serious damage on rubber plantations. The accom- 

 panying figure of the beetle, represented about three 

 times the natural size, may enable rubber planters to 

 recognize a possible enemy. In case of any occurrence of the pest, the stems of all the 

 trees should be carefully searched. The adult beetles will probably be found 

 clinging to the bark of the trees, when they can be easily captured and destroyed. 



Amongst other injurious beetles received during the past month are 

 specimens of a beautiful burnished green Cetoniid " found eating the bark of a 

 lemon tree," in the Kurimegala district ; and a small green weevil {Astycus sp.) 

 said to be defoliating Pig and Apricot trees. Against all such bark and leaf- 

 eating insects, spraying with Paris Green will be found effective. When 

 applied to foliage, it should be mixed with about six times its bulk of lime. 



A small outbreak of a caterpillar pest (Narosa conspersa, Wlk.), on tea, 

 has been reported from the Uda Pussellawa district. Though belonging to the 

 family Limacodidae ( which includes the notorious "nettle-grubs" ) this particular 

 insect has not previously attracted attention as a pest. It does not figure in 

 Watt & Mann's "Pests and Blights of the Tea Plant." 



Another insect that has been sent in as a tea pest is the grub of a 

 beetle (apparently a species of Helops). My correspondent reports that •"these 

 insects are killing out the tea in Teldeniya." Similar grubs were received from 

 Talawakele, a few years ago. I believe these grubs to be merely feeding in 

 decayed wood of stems that have died from other causes. Specimens of the 

 stems received with the grubs have evidently been dead for many mouths. 



