10 



IHE AGKICULTUKAL NEWS 



January 13, 191'; 



INSECT NOTES. 



THE SPINY CITRUS WHITE FLY.-A 

 POTENTIAL PEST OF CITRUS TREES. 

 A paper was recently published in the Journal of Apii- 

 cuUvral Research, Yol. VI, No 12, June 1916, by Messrs. 

 A. L. Quaintance and A. C. Baker, bringing together all the 

 important information about the distribution and food-plants 

 of thirteen species of Aleyrodidae or white ilies which were pre- 

 viously known to attack" the orange, with three nen- species of 

 economic importance. Of the three new species mentioned in 

 the above paper there is one which will be of special interest 

 to all citrus growers throughout the Tropical Americas and 

 the West Indies, since it is already attracting considerable 

 attention in Janiacia, the Bahama Islands, and Cuba. 



This insect is known as the Spiny Citrus White Fly 

 {Alt-uromnihrn uoghnni, Ashby). although it bears other 

 common names in the ditferent localities where it is 

 prevalent.* 



The brief sketch of its early history is taken from the 

 above paper, whi e later details about this new pest are 

 filled in from other sources, including the writer's personal 

 experience with it in Cuba. 



This aleyrodid first came to the notice of the Bureau of 

 Entomology at Washington in June 1910 through material 

 .sent from India, and specimens were also received from the 

 Philippines in that year. Then it was found by E. S. 

 Wogluni to be widely distributed on orange throughout 

 India and Ceylon. 



The first record of its existence in the Western Hemi- 

 sphere came from Jamaica, when in November 1913 specimens 

 were received at the Bureau of Entomology in Washington 

 from Colonel C. Kitchener near Kingston, and more 

 material was sent in 19U by Colonel Kitchener and Mr. S. F. 

 A.shby, Microbiologist at the Jamaica Department of 

 Agriculture. The latter was the first to describe this in.sect. 

 which therefore bears his name after it Ashby con.siders 

 that this insect has been introduced into Jamaica on the 

 mango from the East within the last twenty years. A. H. 

 Eitchie, late Government Entomologist of Jamaica, in his 

 report for 1915-16 says, 'The black fly of citrus (Aleurocan- 

 thvs voghirni) continues to spread, and during the past year 

 two of the largest citrus groves in the island have reported 

 attacks of this pest for the first time.' Eitchie finds that 

 this aleyrodid propagates during the entire year in Jamaica, 

 and, as he has seen it, is capable of greater havoc in a shorter 

 period than the two common white tiies in Florida 

 combined (the citrus white fly and the cloudy-winged white 



fly). 



The spiny citrus white fly was next found in Cuba in 

 August 1915, and specimens were sent to P. Cardin, Entomol- 

 ogist of the Cuban Agricultural Experiment Station. This 

 material was forwarded to Ashby in Jamaica, identified by 

 him as Aleurocanthus woglumi, and in February 1916 verified 

 by Quaintance of the Bureau of Entomology at Washignton. 



This same insect was reported from the Bahama Islands 

 in February 1916 through material sent by L.-J. K. Brace 

 from Nassau (New Providence) to the Bureau of Entomology 

 at W'ashington. Material preserved in alcohol was also 

 received by the Imperial Department of Agriculture in 

 November 1916 after earlier correspondence about this 

 aleyrodid, which seems to be generally prevalent in Nassau, 

 and is apparently spreading rapidly. 



*This insect is .also referred to in current literature as tlu- 

 Citrus Black Fly, and the Citrus Blue Fly. 



It will be seen Irom the above account that the spiny 

 citrus white fly has probably been introduced into the Western 

 Hemisphere from the Easr, and that in this part of the 

 world it is known to occur in the islands of Jamaica, New 

 Providence (Bahamas), and Cuba. 



It may be of interest to readers of the Agricultural 

 Nevs in general, and citrus growers in particular, to have 

 a few notes on this recently established pest of citrus, and on 

 the work that is already being done to control it in Cuba. 



The presence of the spiny citrus white fly in Cuba first 

 became known in August 1915, when it was reported from 

 the Guantanamo valley at the south-eastern end of the island 

 as attacking a few citrus trees in a grove of about 8,000 

 growing on the Finca Montesano. In the course of an 

 inspection made in the early months of 1916 by the Plant 

 Pathologist and Entomologist throughout the citrus-growing 

 districts of Cuba, it was found that this aleyrodid had spread 

 so rapidly in the above-mentioned grove since August 1915, 

 that practically all the trees were infested. This insect 

 was also found to be prevalent in the neighbouring town of 

 Guantanamo. 



Furthermore, this inspection showed that the spiny citrus 

 white fly, in addition to attacking oranges and grape fruit, 

 occurs on other species of citrus, and on several other plants 

 including mango, coffee, guava, sapodilla, star apple, etc So 

 far as is known at present, the white fly in question only 

 occurs in the Guantanamo valley, where there is very little 

 citrus grown commercially, and has not reached the citrus- 

 growing districts to the north-west. 



Prompt measures, therefore, were adopted against this 

 pest with the idea of preventing its spread to the other 

 citrus districts of Cuba. A commission to deal with the 

 more important insect pests and plant diseases of the island 

 was in the process of formation, and the control of Aleuro- 

 cantlati' v:oglumi was among the first problems to be tackled 

 by this commission, as soon as it was established. 



A decree was issued by the Secretary of Agriculture 

 forbidding the exportation of any of the above food-plants 

 or any part of them from this infested area, and prohibiting 

 the importation of these plants from India, Jamaica and the 

 Bahamas. Further, all owners of infested properties were 

 required to report the occurrence of the pest and to help in 

 its control by every means in their power. A brief popular 

 circular in this insect was prepared by the Entomologist for 

 distribution, and an edict was drawn up embodying the 

 above-mentioned decree and giving figures of the spiny 

 citrus white fly as seen on the leaves. This edict has been 

 posted up in placard form throughout the infested region, and 

 in other important places in diiferent parts of the island. 

 Before touching on the control measures, it would not be out 

 of place to give a short description of the spiny white fly as 

 seen by the writer in the field. The duties of the field 

 inspection rendered impracticable the working out of a life 

 cycle of this insect, but the following brief notes on the 

 difi"erent stages may be of interest. 



The eggs when freshly laid appear on the underside 

 of the leaves as minute pearly-white oblong specks, but 

 in the process of development the colour changes through 

 yellow to dark-brown before hatching. Seen from above 

 under a powerful lens they are slightly concave, while 

 from a side view they appear somewhat kidney-shaped. 

 They are usually laid on the younger leaves attached 

 by a short stalk, but can also be found on the 

 older and often heavily infested growth scattered about 

 among the larvae and pupa cases They are sometimes laid 

 in a spiral form, but are generally deposited without any 

 special arrangement. The hatching larvae soon attach 



