346 



them to the fumes of some deadly gas or fumigation. In the 

 case of the external irritants applied as a spray or powder, the 

 entire body of the insect must be covered and every infested por- 

 tion of the plant treated to have the work effective. The oil 

 sprays or washes are the most important remedy for sucking in- 

 sects and the standard one has been the kerosene emulsion. The 

 resin wash is not suited to the Hawaiian conditions because of the 

 fact that this wash acts principally as a coverings to the insect 

 and kills by smothering the pest. Resin wash has been used with 

 success against certain scale insects in California during the 

 rainless season. With the frequent rains here and the neces- 

 sarily greater length of time for the resin wash to act in com- 

 parison to the oil washes, the more active kerosene emlusion 

 should be used. 



It is not deemed necessarv to give in this connection the various 

 mixtures for biting and sucking insects with directions for their 

 preparation, for the reason that the whole subject is discussed in 

 Bulletin No. 3 of this Station, Insecticides for use in Hawaii, 

 which has had a wide circulation in the Territory and can be 

 received free of charge by anyone requesting same. As dis- 

 coveries are made in the preparation of insecticides or the ma- 

 chinery for applying them of value to the residents in the Terri- 

 tory, the information will be published in due time for distribution. 

 Since the character of the remedy and the apparatus for apply- 

 ing it depends entirely on the pest to be treated, the plant it in- 

 fests and the local conditions, it is hoped the Station in instances 

 of insect attack will be informed of the particular pest and the 

 plant infested, and will receive specimens of both, upon receipt 

 of which the fullest possible information will be given to the 

 correspondent, and in so far as is possible, a personal visit of in- 

 spection made. 



CULTURAL METHODS. 



It is a fact accepted by economic entomologists without excep- 

 tion, that a healthy plant can resist to a great degree the attack 

 of an insect enemy. To bring about maximum growth and vigor, 

 we must see that our fruit trees receive a sufficient supply of water 

 and plant food. Also in the various cultural practices we must 

 consider their direct effect on the insect pests ; that is, to control 

 an insect pest by cultural methods, implies more than the practice 

 suitable for the plant itself. For example, in tillage it may be 



