330 



THE AGRICULTURAL NEWS. 



OCTMBB 18, 191S. 



INSECT NOTES. 



POPULAR ENTOMOLOGY. 

 LADY-BIRDS. 



A few months ago a communicated article appeared in 

 one of the Barbaios d<kily papers calling attention to the 

 value of lady-biids in the control of blights of orange trees 

 This article was signed, and its general tone was rather that 

 of finding fault with the Govern- 

 ment because the local ladybird 

 had not been properly utilized for 

 keeping in cbeck the various blights 

 which attack the citrus tees, chieHy i 

 the lime, in Barbados. *vSfe' 



Now, wh.le the intention of the [T^^^ 

 writer of that article was to do good, v4 .'^ 

 he was so uninformed that if any 

 one had paid attention to what he had 

 written, more harm would have been 

 done than go< d. His mistakes were 

 pointed out to him by a friend who 

 was better informed on the subject, 

 atd an attempt was made in a second 



Fig 4 — Lady-Biki 

 article to put the matter in a better (a) Larvae, (b) Empty pup» case, (c) Adult, 

 light. Again his grasp of the subject 

 was so faulty that the second article 

 failed of its purpose and rather ten- 

 ded to confuse than to clear the 

 issue. 



As to the Barbados lady-bird, 

 the case is this. In Barbados the term 

 lady-bird is applied to a large sLowy 

 weevil which is a v' ry serious pest of 

 the sugar cane, while in all other parts 

 of the English-speaking wrld, the 

 insects known as ladj-bird beetles are 

 leneficial insects See Fig 4. 



The insect which is commonly 

 called the lady-bird in Barbados is 

 more properly known as the root 

 borer of the sugar-cane. The tech- 

 nical name of this insect is Diap- 

 repes abbreviatus, Linn. For mere 

 than ten years it has been the canee 

 of very serious injury to the grow- 

 ing sugar-cane in many localities, and 

 sugar planters have experienced severe 

 los-'es in crop a« a result of its depre 

 datiobs. So serious a pest has this 

 insect become that a Commission 

 has been appointed by His Excel- 

 lency the Governor of Barbados to 

 enquire into the root borer disi ase and 

 the means of combating it. The root 

 borer of the sugar cane is a weevil, 

 and weevils as a whole are injurious 

 .insects. 



known as blights on lime and other citrus trees in Barbados, 

 are attacked by all three kinds of natural enemies. 



The writer of the newspaper article referred to above 

 had evidently been reading abint the introduction of a 

 lady-bini into California, and of the success which attended 

 the attempt to control a certain insect pest by this means, 

 and he apparently thought that a ladybird is a lady-bird and 

 a scale insect, is a scale insect, aud that all that had to be 

 dono was to catch an insect called a lady-bird and compel it 

 to eat some insects called scale insects. 



The Cottony Cushion Scale 

 (Icerya purchasi, Maskell) was acci- 

 dentally introduced into California, 

 where it became a most serious pest 

 of orange and lemon cultivations. 

 In i\ustralia this insect occurred 

 without becoming a serious pest, and 

 it was found on investigation that 

 it was preyed upon there by a lady biid, 

 and it was believed that this lady-bird 

 was responsible for keeping the 

 Cottony Cushion Scale in check. The 

 introduction of the Australian lady- 

 bird (^Xoi'is cardinnlis) into California, 

 resulted in a natural check being put 

 on the Cottony Cushion Scale in that 

 State. This was not, however, a pro- 

 miscuous introduction of an icsect 

 called a lady-bird, without reference 

 to its habits, as would be inferred fr^m 

 the newspaper article referred to 

 above, but the result of careful 

 entomological investikations into tie 

 original home of the pest, and the 

 agencies controlling it there. When 

 its natural enemies had been found, 

 they had to be studied as to their 

 value in exercising a check on the 

 increase of the pest, and it had then to 

 be decided which one wag of suliicient 

 importance tc warrant the necessary 

 trouble and expense in the attempt 

 to transport it trom its native home, 

 and introduce it into an entirely new 

 environment 



/^8 a result of this creful study 

 into the habits and relationships of 

 certain insects, a great eflfort in 

 economic entomology was crowned 

 with succo.«si, and a satisfactory 

 degree of control w a s obtained, by 

 natural agencies, over a serious pest. 



Fir, .5.— The Root Boreu of S(n;,\R-CANK 



The ladybird beetles, which are useful insects, be'ong to 

 a large family of which nearly all the members are benefiiial 

 in habit. These beneficial insects do not eat plant tissues ; 

 both the larvae and adults feed upon aphides, scale insects, 

 mealy-bugs and similar insecta. 



Nearly all scale insect.s are preyed upon by natural 

 enemies, among which are internal icsect parasites, prcdaceous 

 insects, and parasitic fungi; and the scale insects which are 



' KNTOMOLOGV.' 

 .\ small pamph'et entitled 'En- 

 tomology', issued and distributed by 

 the nnnufacturers of a certain insec. 

 ticide, contains a few statement.s which may be of inter, 

 est fo readers of \\\^'Ai;ri(ulliiriiI yiivs.. 



Confusion in the use of common names of insects often 

 leads to very considerable errors and an instance of this is 

 given in the article 'Lady bird^' in this issue. 



Inaccurate statements which arise frmi a lack of 

 knowledge of biological facts or of '■■rdinary usagi», as well as 

 carek^ss expression, are not only unreliable but o! ten highly 

 amusing. 



