156 



TWENTY-NINTH FRUIT-GROWERS' CONVENTION. 



Our first law, then: Insects of extreme prolificness must have myriad 

 enemies in their native home; else they would soon multiply to the 

 entire destruction of such plants or animals as supply their daily food, 

 and they would in this very habit commit race suicide. 



Again, almost all noxious insects in California are introduced species. 

 They are often — usually — introduced without their specific enemies. 

 Thus their new home and life are a perpetual and veritable picnic. 

 All undisturbed, they yet retain their tremendous fecundity and they 

 sow ruin with a broad, free hand. Our second law, announced by 

 Darwin, fifty years ago: Introduced species always forge to the top. 

 The conclusion is inevitable. In case of an}^ serious pest, like the black 

 scale, we should seek out its nativity and go at once for its specific 

 enemy. This has already served us in our Vedalia, Rhizobius, Chilo- 

 corus, and Scutellista. The Vedalia already looks after the ruinous 

 cottony cushion scale. The Rhizohii are fast getting their bearings 

 and are promising to eradicate the black and purple scales. The Scu- 

 tellista seems to keenly relish the task of sweeping the black scale from 

 our citrus groves, and we may hope splendid things from the newly 

 introduced Chilocorus similis from northern China, the native home of 

 the San Jose scale. Here comes quickly a suggestion which we should 

 have acted on years ago: We should keep a bright, energetic, competent 

 young entomologist in the field all the time to do just this important 

 work. He will seek out the nativity of all our insect pests. Then he 

 will hasten to the place and secure for importation the specific parasites 

 which will, in their new home, as well as in their old, hold them in a 

 state of "innocuous desuetude." I wonder that, with the startling 

 success which crowned California's first experience in this then wholly 

 novel enterprise, she has been so full of apathy since. I believe we 

 should make all haste to redeem the time and appoint without further 

 delay the right man and hold him exclusively to this promising work. 

 The cottony cushion scale menaced our entire citrus industry. The 

 Vedalia, upon introduction, at once put a stop to the scale's depreda- 

 tions. The Scutellista bids fair to repeat the experience with the black 

 scale. If it does it will save thousands and thousands of dollars to our 

 orchardists. 



Artificial Remedies. — Spraying was the first means employed to stay 

 scale ravages. Kerosene emulsion and the resin wash were used with 

 some success. The lime, salt, and sulphur wash in the deciduous orchards 

 was used on leafless trees in winter. This lessened its cost and made 

 the application easy, and it still holds a place among our cherished 

 insecticides. In the citrus orchards, with their dense foliage, it was 

 difficult to reach all the insects with a spray, and the foliage and fruit 

 were likely to be injured. Partial or complete failure and injury 

 together uttered a double protest of unwisdom, and both kerosene emul- 



