F.ulcn.l ,ll S.iii /o.-t Pi.>/ ntfuc .1.1 ScamJ-ClM^ Mail M.ilhr. 



F»i.ifc>lishe-ci at IS South /Warke-t St., San Jose-, Cetl. 



Volume XIX. Number 49. 



APRIL, 1903. 



MONTHLV, 50 Cents a Year. 



How Insect Pests Are Rept Out 



An Address Delivered by Alexan- 

 der Cra-w Before tHe Agricultural 

 Club of BerKeley. 



It is an accepted scientific truth that 

 the worst of our insect pests are those 

 which have been introduced among ua 

 from foreign countries. It is also a fact, 

 well known to science, that in every 

 country to which an insect is native, 

 there are other insects, parasitic or jire- 

 deceous, whii'h prey upon it, and keep it 

 below the danger limit, and while there 

 may be seasons in which some species of 

 insects increase more rapidly than others 

 and for a time seem to be a threatening 

 danger, nevertheless their checks soon 

 overtake them and they are removed 

 from the Hat of active pests, their depre- 

 dations being on too small a scale to do 

 very serious damage. It is on the basis 

 of these two facts that the operations of 

 the Quarantine Department of the State 

 Board of Horticulture have been con- 

 ducted. First, to keep out of the State 

 all new pests; secondly, to discover and 

 introduce the natural enemies of those 

 which have already obtained a foothold 



liere. 



In the conduct of the first we have a 

 very thorough system of quarantine es- 

 tablished, and it is very dillicult to bring 

 plants into the State until they have been 

 first examined and passed upon by an 

 officer of this Board. Under our law it 

 is required of all transportation compan- 

 ie.s that they notify either the Chief Hor- 

 ticultural Quarantine officer, or some of 

 his assistants, of the importation of any 

 trees, shrubs or nursery stock into the 

 State. In San Francisco, or any countj* 

 where there are no Horticultural Quar- 

 antine Guardians, this information is 

 sent to the main office. But in those 

 counties where there are Boards of Hor- 

 ticulture, the local officers are notified. 



Most of the fruit growing counties have 

 their County Boards of Horticulture, and 

 in the more important fruit sections, 

 these County Boards divide the County 

 into Districts and a Local Inspector is 

 appointed for each district. Under the 

 law their labors are confined to local 

 work and their powers are abridged. 



To overcome this, they have received 

 commissions from the State Board of Hor- 

 ticulture as State Quarantine Guardians, 

 so that they can act in the dual capacity 

 of county and State officers. By this 

 means, we are enabled to inspect all 

 stock tliat finds its way into tlie State. 

 This is all cirefully examined. If it is 

 free from pests it is released, but if found 

 infested with insects or diseases, it is 

 dipped in some solution or fumigated 

 with hydrocyanic acid gas, or destroyed 

 altogether, as tlie case demands. There 

 are some pests that we have not got in 

 the Stiite and which cannot be certainly 

 killed by any of our processes; witii 

 these, no chances are taken, but they, 

 with the plant on which they are found, 

 are destroyed by burning. After treat- 

 ing infested stock, if there is any doubt 

 as to the <lestruction of the pests, it can 

 bo held in quarantine until there is no 

 further doubt of the cleanliness of the 

 plants, when they are released. By this 

 means we have succeeded in keeping 

 more serious pests out of the State than 

 we now have in it, and it is hard to state 

 what would have been the result had our 

 doors been open for the admission of any 

 and everything that came along. All the 

 pests witli which we have to contend and 

 which have cost the fruit growers so 

 many millions in loss and labor, have 

 been imported into the State, and all of 

 them before our present effective system 

 of horticultural quarantine went into ef- 

 fect; since then, none have found a foot- 

 ing here, although hundreds have been 

 stopped from entering. To mention a 

 few of our imported pests, we have the 

 San Jose scale, probably from China, 

 tlie cottony cushion scale from Australia, 

 the codlin moth from Europe, the red 

 scale of the orange, from China, the 

 black scale, the soft brown scale, the 

 brown apricot scale, and in fa.t the whole 

 list that have been destructive to our 

 fruit interests, these have all found en- 

 trance to our State from the outside be- 

 fore there was any means to stop them 

 at the entrance, and I need not remind 

 you what those undesirable immigrants 

 have cost and still are costing us. 

 Having got these pests, the next great 



thing was to get rid of them or at least 

 reduce them to a state of "innocuous 

 desuetude." To this end we have en- 

 deavored to discover their native land, 

 to trace their wanderings until they 

 lauded on our hospitable shores, and 

 when we have found this place we have 

 always found that they existed in very 

 limited numbers, and sometimes even it 

 was difficult to find them at all. In the 

 case of the cottony cushion scale, for in- 

 stance, which we knew positively came 

 originally from Australia, when Mr. Al- 

 bert Koebele went there to find its nat- 

 ural enemy he was laughed at, as the 

 cottony cushion scale was hardly known 

 there, and its natural enemy was not 

 known at all, of so little importance in 

 its native land was this insect, which a t 

 that time was such a terrible scourge to 

 the orange growers of California. But 

 Mr. Koebele well knew that inasmuch as 

 the scale did not spread, and as it was 

 not a pest there, that there must be some 

 natural enemy at work upon it, and he 

 perservcred until he discovered wlat he 

 was searching for, and the result of his 

 labors is shown in the orange shipments 

 from California today, for it is safe to say 

 that wore it not for the work of the Ved- 

 alia cardinalis on the white scale, there 

 would be no oranget now produced in 

 California. So, having found the native 

 habitat of our enemies, which has not al- 

 ways been an easy task, we have next 

 sought for their parasites, and have 

 found, introduced and distributed a great 

 many, some of which have done e.vcel- 

 lent work in reducing the number of the 

 injurious pests. So thorough has been 

 the work of parasites on the scale insects 

 of this State that we may say that we 

 have but two scales that can now be re- 

 garded as really bad pests ; these are the 

 purple and the red scale, and on the latter 

 there are now parasites at work from 

 which we have great hopes. The black 

 scale, which has been a serious pest over 

 the greater part of the State, has now 

 disappeared over the larger portion of 

 Northern California, while the brown 

 apricot scale has met its match in the 

 Comys fusca. In the soft brown scale 

 we have several parasites, and the San 



