TWENTY-NINTH FRUIT-GROWERS' CONVENTION. 



143 



must be considered injurious, and the greater their numbers the more 

 destructive will their presence be to the trees attacked. Some injurious 

 insects are more or less restricted in their food habits or tastes; again, 

 others attack a great variety of plant life, and on this account are 

 difficult to control by artificial methods such as poisons, sprays, or 

 fumigation. In the great majority of cases the latter method is the 

 most effective, as it is far reaching and deadly, if sufficient chemicals of 

 the proper strength are used and the tents or fumigating rooms are gas 

 tight. Fumigation is a California invention forced upon us by the 

 imperfect results from spraying — even by experts — owing to the impos- 

 sibility of reaching every part of an orange tree with its dense, evergreen 

 foliage. Even fumigation with hydrocyanic acid gas in recent years 

 has not been entirely satisfactory, possibly because of inferior grades 

 of cyanide of potassium or defects in the tents. The orchardists them- 

 selves are probably to blame in a great measure, for they have demanded 

 lower prices for the chemicals and given the contracts for the work to 

 the lowest bidders, and thereby produced a state of affairs that has led 

 to economizing both in materials used and in time spent in the work. 



Artificial methods have in no instance exterminated or even pre- 

 vented the spread of insect pests when once established in a district. 

 Of course, their too rapid increase and spread have been checked to 

 greater or less extent by such remedies, and it would be the height of 

 folly to await the advent or introduction of a parasite or beneficial 

 insect to destroy a pest when it can be destroyed in great numbers by 

 either spraying or fumigation. Extermination is out of the question 

 with either method; the work has to be repeated at least once a year, 

 and in the case of certain insects, from two to six sprayings are neces- 

 sary in order to save the crop (as with apples and pears) from destruc- 

 tion by the codling-moth. No member of the late Board of Horticulture, 

 or the Commissioner of Horticulture, or any one connected with his 

 department, has ever advocated the laissez /aire, or "let alone policy," 

 with respect to the control of injurious insects for which we have no 

 parasite or predaceous insect enemy. On the contrary, this department 

 has issued numerous bulletins giving directions in the methods of spray- 

 ing and fumigating orchards. Californians do not believe in the "let 

 alone policy" or "wait for something to turn up" and destroy the 

 destructive insect pests that were introduced into the State during the 

 years we had the open door for everything in the tree or plant line 

 with accompanying insects, not in myriads, but a few scattering scales 

 or clusters of insect eggs. Once introduced and established, without 

 their natural checks, man's wisdom has proved puerile in his efforts to 

 exterminate such pests or even prevent their spread. It was only after 

 very heavy loss and expensive experience that we determined to try 



