TWENTY-EIGHTH FRUIT-GROWERS' CONVENTION. 



103 



Horticulture in this State has been damaged many millions of dol- 

 lars by the bringing in of pernicious insects without their parasites. 



The cottony cushion scale (Icerya purchasi) alone, would ere this 

 time have made California a barren waste, if no parasite had been found 

 to arrest it in its fearful ravages. It devoured all vegetation except 

 cone-bearing trees, and human effort was powerless to suppress it. The 

 little Australian ladybird (Vedalia cardinalis) came to the rescue, and 

 in an incredibly short time brought relief. This and many other bene- 

 ficial insects have been introduced through the efforts of the State Board 

 of Horticulture. There are other destructive scales which we have been 

 fighting for twenty years with washes, sprays, fumigation, cutting off of 

 tops, trunk scrubbing, etc., and have learned in the last few years to keep 

 them fairly in check. In doing this, however, we have expended hun- 

 dreds of thousands of dollars, and lost in quantity and quality of fruit 

 and tree a vast sum of money, and the fight and expense still go on. 



Except the cottony cushion, the most destructive scale to citrus trees, 

 and among the most difficult to kill, is the red (Aspidiotus aurantii). 

 The yellow (Aspidiotus citrinus) and the black (Lecanium olese) have 

 also been a heavy tax on tree and purse. The deciduous trees (apricots, 

 prunes, pears, etc.) have their share of scales. 



With two exceptions, the codling-moth (Carpocapsa pomonella) and 

 the purple scale (Mytilaspis citricola), there are, for all these hosts of 

 harmful insects, legions of parasitic and predaceous ones to keep them 

 restricted to comparatively harmless numbers. 



Now it is not so much whether we have or have not parasites, as it is 

 what they will accomplish. In order that we may have some idea as 

 to what may reasonably be expected, we will refer to a few instances 

 out of many as precedents for faith in their efficiency. Florida, about 

 1835-1840, believed her orange groves doomed to utter ruin, but they 

 were rescued by a little chalcid fly. Australia had a like experience. 



In the early fifties, according to reliable report, the orange groves of 

 California were being destroyed by the soft brown scale (Lecanium ties- 

 peridum); some trees were killed, others were following to the same 

 fate. No fight was made by the grower, except to cut off the tops and 

 scrub the trunks of the trees; spray or fumigation not having been intro- 

 duced. In time the chalcid fly (Coccophagus lecani) put in an appear- 

 ance, freed the groves from the pest, and let them return to their former 

 beauty and fruitfulness. 



The citrus groves of the San Gabriel Valley, for many years greatly 

 damaged by the yellow scale, have been freed by the golden chalcid fly 

 (Aspidiotophagus citrinus). And now come reports from all along the 

 coast of the disappearance of scales, especially of the black and San 

 Jose, as result of the work of parasites. 



In further evidence of the value of parasites, I will state conditions 



