Plant Sanitation, 



296 



[May 1907. 



NOTE ON ABOVE BY THE GOVERNMENT ENTOMOLOGIST. 



Considering the burial of primings from an entomological point of view, 

 this treatment is undoubtedly useful in the reduction of many insect pests, but is 

 not so efficient as burning. It is seldom that prunings are so completely buried as 

 to prevent the escape of a certain proportion of the insects that may be infesting 

 them. 



But though— regarded as a direct means for the control of insect pests- 

 burial is inferior to burning, it has a distinct indirect effect in improving the health 

 of the plant and so enabling it to better withstand its enemies, This effect has been 

 repeatedly noticed in the case of ' shot-hole borer.' Fields in which the prunings 

 have been buried, w ith a sufficiency of lime, have continued to give good and even 

 increasing crops in spite of the constant attacks of the borer ; while fields in which 

 the prunings have been systematically burned — year after year — without the addition 

 of an equivalent in nitrogenous manures, have steadily decreased in yield. 



This improvement following the burial of prunings is probably dependent 

 upon the incompleteness of the process -vide the Mycologist's remarks upon the 

 conditions necessary for the proper development of the nitrifying bacteria. 



E. ERNEST GREEN, 

 Govt. Entomologist. 



Royal Botanic Gardens, Peradeniya, 20th March, 1907. 



[Burial of prunings is obviously one of those matters about which at present 

 no hard and fast rule can be laid down. It may depend, for instance, upon whether 

 the field is subject to root disease or to shot-hole borer— Ed. T.A.] 



Entomological Notes. 



By E. Ernest Green, Government Entomologist. 



I have received an interesting communication from a correspondent in the 

 Nilambe district who reports the successful treatment of ' Nettle Grubs ' (Thosea 

 recta) by spraying with Jeye's Fluid. He writes:— "To commence with I used 

 three ordinary cigarette tins of Jeye's Fluid to a Kerosene oil tin of water. At this 

 strength it killed all the grub within three or four hours. But I found it injured 

 the young shoots, so tried two tins of the fluid to one oil tin of water. Directly 

 the bushes were sprayed, all the grubs at once fell to the ground. After about 

 six hours I found about 50 per cent, dead and the others climbing up the trees 

 again ; but as far as I can judge they did no more damage, and in four days I could 

 not find a living one on the bushes, nor have the bushes that were sprayed been 

 reinfected. The proportions of mixture were one part of Jeye's Fluid to 35 parts 

 of water." The total cost worked out at approximately Rs. 2"25 per acre. 



Cacao on an estate in the Moneragala district has been seriously affected 

 by Helopeltis. Both the young foliage and the fruit are said to have suffered 

 severely. This excessive attack has followed closely upon the removal of all the 

 shade trees. 



The Funtumia (Kickxia rubber) trees on the same estate as elsewhere are 

 repeatedly defoliated by the leaf-rolling caterpillar of a moth ( Caprinia conchy lalis). 

 There is no practical remedy for this pest which is an indigenous insect, breeding 

 on various local shrubs. Any treatment can be only temporary and fresh attacks 

 are bound to occur. 



I have on more than one occasion received reports of reputed damage to 

 rubber plants and stumps by Dragon-flies, and a detailed statement of such 

 supposed damage appeared in one of the local papers some weeks ago* The Dragon 5 



