ON METHODS OF PREVENTING INSECT ATTACK 45 



insects he will have early information that an attack on a severe scale is 

 imminent, and will be able to take his measures in time to combat it. 

 And to be ready for such an attack means the possibility of stamping it out 

 before it assumes proportions against which nothing short of felling on a 

 wholesale scale will make headway. Trees felled in this manner partake 

 of the nature of what are called "trap trees," the use of which will be 

 described later on. 



With regard to the prevention of damage from insects when we have 

 ascertained that an attack is imminent, the measures that can be put in 

 force depend to a great extent on the staff available. In many parts 

 of India the staff is still so inadequate in proportion to the large areeis to 

 be dealt with that proposals for taking action to prevent attacks are difficult 

 to suggest. 



The judicious use of tire on an area where it is kncnvn that an insect 

 is passing through its pupal stage amongst the dead leaves or humus or in 

 the first' inch of the soil on the forest floor will be dealt with in the next 

 section. Much might, I think, be done in this manner, provided the proper 

 amount of attention can be given to the work. As we shall see, a number 

 of pests are to be found in this position; many caterpillars pupate here; 

 the sal Monophlebns lays the bulk of its eggs on the ground, and so on. 



In the case of the bark-boring beetle and caterpillar pests the pre- 

 vention of attacks is easier. With the caterpillars the first beginnings of 

 an attack are usually easily seen on the bark, and can be dealt with if the 

 life history of the insect is understood. The first beginnings were noted 

 with the commencement of the bark-eating Avbela attack in the casuarina 

 plantations in Madras in 1902-3. Had the life history been known and 

 the trees affected been cut out and the caterpillars killed, what proved 

 eventually a disastrous infestation in some plantations might have been 

 nipped in the bud. 



Bark-beetle attacks usually commence at a centre or several centres, 

 and spread outwards. If these centres are marked down and the infested 

 trees promptly cut out and burnt the attack will be stopped in its initial 

 stages and the rest of the forest saved. The "trap trees," to which I have 

 already alluded, will give the necessary warning that such an attack is 

 imminent. 



4. Methods of Combating Attacks in Progress. 



The methods to be put in force to counteract and stamp out attacks of 

 pests which have assumed serious dimensions vary with the lite histories and 

 consequent method of attack of the insects concerned. 



The methods required to combat the attacks in trees either standing 

 or lying felled in the forest differ from those which must be put in force to 

 stamp out attacks of wood-borers pure and simple in wood-stacks or piles 

 of bamboo, whether these are standing on roads in the forest or in depots. 



