144 



TWENTY-NINTH FRUIT-GROWERS' CONVENTION. 



nature's method and introduce the insects that keep such pests under 

 control in their native country. 



It has been claimed that the same insects have always been in exist- 

 ence and the same fruits have been cultivated in the Old World for 

 centuries, and that therefore we have no reason to become alarmed; but 

 in those countries the orchardists were content to propagate and grow 

 the same varieties which their grandfathers grew, and there was little 

 danger of introducing new pests. In the newer portions of the world 

 w^here fruit-growing has assumed the commercial importance that it has 

 in the United States, and especially in California, the balance of nature 

 has been upset and we are paying for our ignorance of her laws. %he 

 pioneer orchards — I now refer to those planted before 1849 — were 

 mostly grown from seedling trees or propagated from locally-grown 

 trees and were free from pests. The orange and lemon trees were bright 

 and free from smut. The bright and thrifty condition of the trees 

 induced our pioneers of the fifties and sixties to bring or send for new 

 varieties. The "soft brown scale'' {Lecanium hesperidum) was intro- 

 duced into the orchards and gardens of Los Angeles, and spread with 

 alarming rapidity. Orange trees were killed by that scale and orange- 

 planting was stopped. Years passed, and the parasites of this scale 

 were unintentionally introduced upon other plants, and now this scale 

 is not classed as a pest, unless where the constant presence of ants pre- 

 vents the parasites from accomplishing their destruction. The parasites 

 of this scale are both chalcid flies. One, Coccophagiis lecanni, is para- 

 sitic of the small scales, and the other, Encyrtiis flavus, attacks the 

 full-grown scale. The former deposits but one egg in each scale, and the 

 Encyrtus from one to eight, and each egg develops into a maggot and 

 then into a perfect fly — all under the scale, so you can understand they 

 are exceedingly small insects, each with four wings, six legs, and two 

 antennae. The orange-growers overlooked such diminutive insects, and 

 their valuable work was ascribed to some mysterious disease, or as 

 several growers stated, "the scales had run their course and were 

 naturally dying out.'' 



The next serious scale that was introduced was the ''black scale"' 

 {Lecanium olese). This is a more general feeder, and besides olive trees 

 it also attacks the orange, lemon, lime, plum, peach, apricot, pepper, 

 oleander, crat^gus. pittosporum. abutilon, pelargonium, photinia, and 

 a variety of wild shrubs and weeds. AVe have a native internal parasite, 

 Tomocera calif ornica, that in some seasons destroys from 25 to 75 per 

 cent, but as each scale produces from 1,500 to 2,500 eggs, it will be 

 readily seen that this parasite alone could not cope with such a pest, as 

 it has but one generation each year. ' Another internal parasite is 

 Aphelinus mytilaspidis. a more slender species but not so prolific. The 

 "black ladybird"' (Bhizobius ventralis) was introduced from Australia 



