August, 1910,1 



lis 



PLANT SANITATION. 



ENTOMOLOGICAL NOTES. 



By E. Ernest Green, 

 Government Entomologist, 



(Illustrated.) 



The Castilloa Scale-Bug. 



In my last series of Entomological 

 Notes I recorded the discovery of a new 

 kind of scale-bug (Inglisia sp.) infesting 

 Castilloa rubber. I have, since then, 

 paid a visit to the estate upon which it 

 occurred, and have made a thorough 

 examination of the pest in situ. 



The 5-acre clearing of 1\ year old trees 

 was completely over-run by the bug- 

 Not a single tree had escaped infection- 

 The insects were encrusting the under- 

 surface of all the lateral branches and 

 enveloping the vertical leaders. It was 

 also present— especially in its earlier 

 stages— on the undersurface of the 

 leaves, lining the midrib and mote 

 prominent lateral veins. The effect 

 upon the trees is not so great as might 

 be expected from the virulence of the 

 attack. There was no excessive fall of 

 leaf. A few of the leaders were dying 

 back, but it is doubtful if this was due to 

 the presence of the bug. Other leaders, 

 though thickly encrusted, appeared to 

 be otherwise healthy. 



There were occasional plants of Crota- 

 laria striata, Chili, and Lantana growing 

 beneath the infested Castilloa trees. 

 The Crotalaria was regularly attacked, 

 but the other two plants were untouched 

 —though thickly sprinkled with the 

 viscid excreta of the insect. The Chili 

 plants appeared to be dying from this 

 cause alone. 



A Hevea rubber tree that was grow- 

 ing with its branches intermingled with 

 a badly infested Castilloa was quite free 

 from infection ; nor could I find any 

 signs of the pest on other Hevea trees in 

 an adjacent clearing. 



At one edge of the Castilloa clearing 

 was a hedge of jungle plants, of which 

 the following species were found to be 

 attacked :—Solanum sp., Vernonia sp., 

 Greivia microcos and Ade?iochlama zey- 

 lauica. These had unmistakably been 

 infected from the Castilloa and could 

 not be regarded as the original source of 

 infection, as the bug was not to be fouud 

 upon similar plants beyond the reach of 

 tne Castilloa. 



If the pest were confined to Castilloa 

 and a few jungle plants it would not be 

 of so much importance. But it takes on 



a much more serious aspect by the dis- 

 covery that it was attacking tea in a 

 most determined manner, A number of 

 small tea bushes, in a young clearing 

 adjoining the Castilloa, were very badly 

 attacked, the main stems and branches 

 being thickly encrusted by the bug. 



The' original source of infection re- 

 mains undiscovered, It is improbable 

 that it could have been imported with 

 living Castilloa plants. It is a new and 

 hitherto un described species of scale- 

 bug and— as far as is known- this is the 

 only locality in which it has appeared. 

 One can only suppose that it occurred 

 locally as a scarce insect upon some 

 indigenous plant, until it found a more 

 congenial food in the introduced Cas- 

 tilloa plants. 



The pest was first observed at the 

 end of 1908, on a small patch of the 

 Castilloa trees, but little notice was then 

 taken of it, as it was mistaken for the 

 common lantana-bug. It quickly spread 

 through the whole clearing. At the 

 time of its first appearance, a small 

 piece of adjoining scrub-land had just 

 been cleared and planted with tea. It 

 has been suggested that the bug had 

 been living in this scrub and was driven 

 out into the Castilloa when its original 

 home was destroyed. But this hypothesis 

 is improbable. The clearing was burned, 

 aud any existing pest would have been 

 destroyed with it. 



The original Castilloa clearing is so 

 badly infested that the cost of cleansing 

 it would be prohibitive. The only thing 

 to be done is to cut down the trees, score 

 them from end to end and extract every 

 ounce of rubber from them, aud burn 

 them. It does not appear that this will 

 be any serious loss, as this species of 

 rubber tree is not fouud to be very 

 profitable in Ceylon. 



But the infection of the tea is a more 

 serious matter and calls for very careful 

 attention. From the appearance of the 

 bushes already infested, I am led to 

 believe that it this pest is allowed to 

 establish itself, and to become widely 

 distributed in the district, it will prove 

 to be a very dangerous enemy of the tea 

 plant. Immediate steps should be taken 

 to eradicate the pest fiom the small 

 clearing in which it now occurs. The 

 affected bushes should be cut down to 

 (say) 9 inches. The primings should be 

 burnt in situ while still green, and the 

 stumps should be painted over with 

 some soapy insecticide such as ' Vermi- 

 sapon ' or 1 Macdougall's Wash,' In view 

 of the possibility of the pest recurring 



