PROCEEDINGS OF THIRTY-THIRD FRUIT-GROWERS ' CONVENTION. 165 



take place. The general hatches occur from April 15 to May 15, June 

 15 to July 15, August 15 to September 15. These times vary as the 

 weather varies. 



The habits of this scale confine it strictly to citrus trees. They prefer 

 the most sheltered part of the tree, or the side that gets the least sun. 



The injurious effect on the trees is very marked. The feeding of the 

 scale on the leaves and branches has a poisonous effect, causing the 

 badly infested branches to die, especially after the colony has become 

 very numerous, as it surely will if not checked. 



AYhile this scale is slow to breed as compared with some, a large per- 

 centage of them mature. There are but few known parasites that prey 

 upon them. This scale thrives and flourishes best near the coast. Heat 

 and a dry atmosphere, like the summer weather in the San Joaquin 

 Valley, soon destroy them. 



From numerous experiments conducted by the Horticultural Com- 

 mission and Inspectors of Los Angeles County, made within the last 

 eighteen months, we find it is possible to destroy the purple scale in 

 all stages by fumigation with heavy doses of hydrocyanic acid gas, and 

 as this scale is confined to citrus trees only, it is possible to make a 

 complete extermination of them. 



Wm. Wood. 



quarantine. 



The inadequacy of the present law, in regard to a proper protection 

 against the introduction of pests dangerous to our fruit and plant 

 interests, can not be more forcibly illustrated than by calling attention 

 to the various points in our State that have recently been ravaged by 

 the white fly {Ale yr odes citri) . 



The failure on the part of the authorities to provide effective quar- 

 antine in these as well as other portions of the State has made it 

 possible for the introduction and spread of this most dangerous of insect 

 plagues. 



The inefficiency of the postal laws governing the transmission of 

 plants and trees through the mail is the most serious drawback to proper 

 control with which we have to contend; the rules laid down for the 

 sending of immoral matter, letters with fraudulent intent, or for black- 

 mailing purposes are exceedingly effective. This would seem to estab- 

 lish the fact that when the moral or material welfare of the people 

 is threatened the law is sufficiently elastic to govern in the premises. 

 However that may be, under the present conditions an inexperienced or 

 careless nurseryman from any part of the United States may send 

 the most dangerous of scale or other infested plants and trees to any 

 point with impunity, where they by diffusion could work ruin to many 

 of the great industries of the State, despite the Boards of Horticulture 

 or local laws. 



