560 



Farrand (A. H). Killing timber by ring barking and poisoning, as 

 practised in New South Wales. — Queensland Agric. Jl., Brisbane^ 

 May 1915, pp. 191, 192 and 225. 



Suggestions have been made that the attack of insect pests may 

 possibly be prevented by the injection of poisonous matter into the 

 sap stream of the tree [see this Revieiv, Ser. A, iii, pp. 73 and 394]. 

 Poisoning with arsenic has been extensively practised in Queensland 

 in recent years for the purpose of clearing land for agricultural use. 

 The tree is " frill ringed " near the bottom and the arsenical solution 

 poured into the space between the lifted bark and the wood, the 

 poison rises with the sap and the tree is killed above the ringing, the 

 bole and roots survive and yield a heavy crop of suckers. It is stated 

 that if the arsenic be applied on one side only the effect is limited to 

 the part of the tree above the point of application and to the branches 

 arising from it. The arsenical mixture used consists of 2 lb. white 

 arsenic and 1 lb. caustic soda in 2 gallons of water. This is a very 

 strong solution, but the use of arsenic for poisoning trees sufficiently 

 to prevent insect attack without damage to the tree or the poisoning 

 of its fruit does not appear to be very feasible. 



Jarvis (E.). Coping with the Cane Grub. — Queensland Agric. Jl, 

 Brisbane, May 1915, pp. 220-222. 



The ideal methods of combating the cane beetle are those which 

 succeed in destroying the female before oviposition, at the same time, 

 the greater length of the larval period enables control measures to be 

 practised for at least six months while the pest is imderground and is 

 subjected to certain forms of climatic and natural control which do 

 not affect the adult. The following methods of checking the larva 

 are given, the figures indicating the order of efficiency and 

 practicability :• — {a) Direct and remedial methods ; (1) incorporating 

 with the soil by cultural operations some enduring substance which 

 will prove fatal to the larvae and at the same time possess manurial 

 properties ; (2) the application to cane furrows of an inexpensive 

 deterrent sufficiently obnoxious and durable to protect a limited area 

 containing main roots from invasion during most of the growing season ; 



(4) fumigation of the soil with a gas fatal to the larvae, but having, 

 if possible, a stimulating effect on vegetation ; (7) applying an 

 insecticidal solution to the main roots. (6) Preventive methods ; 

 (3) collecting grubs by hand ; this method is extensively practised 

 and is of great importance, though theoretically no. (1) — which is still 

 in the experimental stage — must ultimately prove superior to it ; 



(5) exposing grubs to the sun and attacks of natural enemies ; 

 (8) encouraging a vigorous root development and conditions favourable 

 to conservation of moisture by manuring and thoiough cultivation ; 

 (10) clean cultivation during the growing season, (c, Natural control ; 



(6) infecting the soil artificially with " Green Muscaidine " fungus or 

 other parasitic disease ; (9) promoting the protection of indigenous 

 grub-eating mammals and birds, together with the preservation, when 

 feasible, of insect enemies of cane beetles ; (11) the introduction of 

 parasitic and predaceous insects ; (12) the destruction where prac- 

 ticable of a Bombyliid hyperparasite which materially checks the 

 increase of paiasitic " digger wasps." 



