59 



" If we could but discover a mode of increasing these insects at will, we 

 might not only clear our hot-houses of aphides by their mean 1 *, but render 

 our crops of hops much more certain than they nosv are." 



This is one of the earliest suggestions made regarding the artificial 

 production of parasites. It is rather a significant fact that though this lady- 

 bird (Coccinella septempvnctatd) is often so abundant in Kent that they are 

 either blown out to sea in such quantities that the returning tide sweeps 

 them up in long ridges along the sea shore, or else they cause quite a scare 

 by swarming into the houses in the summer time ; yet the hop aphis 

 regularly occurs every few years as a very serious pest. I, with many of 

 the leading entomologists of the world, contend that, while we quite 

 recognise the importance of parasitic insects in the work of keeping down 

 insect pests under natural conditions of climate and cultivation in their own 

 land, yet we certainly dispute the statements continually being made that 

 every pest (and they even proposed to cure the bacterial disease "pear 

 blight" in California with a parasite) can be dealt with by finding and 

 introducing parasites from the country whence the pest is supposed to have 

 originated. Many entomologists and collectors are so imbued with this idea 

 that they have formulated the statement, "That every insect is kept in 

 complete check in its native home by a parasite ; therefore, only find the 

 exact locality of an insect that has become a cosmopolitan pest, and there 

 you will find its parasite ; introduce that parasite, by any means, into the 

 adopted home of the cosmopolitan pest and it is exterminated." Many of 

 them even go further than this ; they claim that we should give up all 

 artificial or mechanical means of killing off our pests, for it is a waste of time 

 and money ; that we are foolishly wasting money in spraying, fumigating, 

 and burning up infested fruit and cuttings, because we are killing all the 

 native and introduced parasites, and not giving them a chance to prove 

 themselves. Now it is only rational to demand that when money has been 

 expended in introducing a parasite into the orchards it should be protected, 

 and if this is carried out to a logical conclusion, we must stop all other 

 methods. This has been done in certain parts of California, under the 

 powers possessed by the Horticultural Commissioners ; and, if the theory be 

 sound, should, in the experiments that have been going on for twenty years, 

 have proved itself. But if we turn to the last report of the Fruit-growers* 

 Convention, held at Riverside only last May, we will be convinced that 

 parasites alone have not achieved the end that their advocates promised the 

 orchardist. 



At the present time, too, both the State and Federal authorities are 

 carrying out elaborate experiments in fumigating in southern California 

 because the scales have become so destructive on the citrus trees. Here 

 also (page 49), Mr. Maskew, a well-known authority in California, says : 

 " The status of parasitism in the citrus orchards, in my opinion, is this the 

 United States Department of Agriculture, through the Bureau of Plant 

 Industry, has proven to you that to have your fruit carry well, and hence 

 sell profitably, it must come to the packing-house clean. The citrus orchards, 

 of southern California to-day cannot send the fruit to the packing-house 

 clean. You can draw your own conclusions from that." 



If wishing for popularity, nothing could be simpler than to advocate the 

 adoption of parasitic methods, for there is a certain amount of plausibility 

 in the theory of introduced parasites to eradicate all pests that appeals to 

 the general public, who have not gone into the why and the wherefore of the 

 matter, and particularly to the orchardist, who naturally wishes to give up 

 spraying and fumigating, if he can simply turn out a colony of parasites, sit 



