66 



or in the ground. From this resting condition the full grown in- 

 sect emerges, and this period of an insect's life is usually de/oted 

 to reproduction, the food, stored up as fat during the caterpillar or 

 grub stage, being sufficient, in many cases, also for the perfect in- 

 sect. All insects do not pass through ' these well-marked stages 

 but no insect has wings until it has attained its perfect shape. 

 These facts must be remembered in dealing with moths, butterflies, 

 beetles and two-winged flies, as it is often possible to find one 

 stage in their life when some remedy will be particularly effective. 



Insects may be caught in several ways. The grubs of boring 

 beetles can usually be cut out of the trees they attack. This must 

 be done carefully, with as little injury to the tree as possible and 

 the wound should be immediately tarred over. Trap logs are use- 

 ful in some cases. If it is found that the perfect insects will attack 

 other trees logs of these trees may be left lying on the ground to 

 attract the beetles. These must be visited periodically and burnt 

 when they contain a large number of the insects. Catching the 

 perfect insects by hand, as in the case of cacao beetles or grass- 

 hoppers, and catching them in trays of molasses are also often 

 valuable methods. 



The selection of particular methods depends on a knowledge of 

 the habits of the insects, and the methods need to be modified to 

 suit different insects. It is often convenient to catch some insects 

 at one particular stage. Thus, boring insects are often well hidden 

 in their early stage but emerge when they become perfect, then 

 they may be caught. On the other hand, it is easier to destroy the 

 caterpillars that eat many plants than it is to kill the butterflies or 

 moths into which they eventually turn. Occasionally the eggs is 

 the most readily destroyed stage in an insect's life. It is desirable 

 therefore that full advantage should be taken of these points. 



The use of poisons offers a method that is generally applicable 

 to insect attacks. Poisons ar^ of two kinds, iX Stomach-poisons " 

 and " Contact poisons ". The former destroy insects when eaten 

 with their food, the latter destroy them when they come in contact 

 with their bodies. Insects that bite leaves, bark or fruit and eat 

 what they bite, can be killed by putting a stomach-poison on their 

 food. These poisons are enumerated in list A. Clearly, this 

 method is of no use against sucking insects, which push a slender 

 tube into the plant and do not eat the outside. For these, contact 

 poisons are used, and since many sucking insects are fixed to the 

 plant or move but little, this method is very effective, for such poi- 

 sons see list B. 



A number of poisons are enumerated below, with directions for 

 preparing them. By their aid the greater number of insects may 

 be destroyed, provided the applications are thorough and system- 

 atic. There are many insects that need special treatment and the 

 application of these poisons needs slight adaptation in many cases. 

 A knowledge of the habits of the pest is the surest guide to good 

 results, and the least amount of treatment will then give the desired 

 result. Substances poisonous to man should not be applied to 

 fruit or vegetables immediately before they are to be picked. 



