PUBLIC RECORD OFFICE
Reference :-
EPERHC.O. 885
20 PUBLIC RECORD OFFICE, LONDON
ALLY WITHOUT PERMISSION OF THE COPYRIGHT PHOTOGRAPH-NOT TO BE REPRODUCED PHOTOGRAPHIC-
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I desire also to express thanks to Dr. E. A. Back and Mr. W. W. Gothers, of the United States White Fly Station at Orlando, for courtesy shown during my
visit.
1
SUMMARY.
Two
The citrus white fly is the principal insect pest of citrus trees in Florida. other species of white fly occur which are of minor importance. The purple, long, and Florida red scales also occur in Florida as citrus pests generally of less import ance than the white fly.
These insect pests are capable of being held in check, generally, by means of beneficial fungi, of which there are nine species in the State. Six of these are known to occur on white fly, one on both white fly and scales and two on scales. In years of abundant moisture the fungi assume a varying degree of control of white fly and scale insect pests by natural methods. In other seasons they may be established during short rainy periods by artificial means, of which the spore spraying is the most satisfactory. Even in favourable seasons that fungi may be assisted to assume control more quickly by artificial introduction. Some six to eight weeks may be gained in this way.
When, for any reason, the pests become so numerous that treatment is required at once, the trees may be sprayed with oily or soap mixtures or fumigated without injury to the fungi.
Hymenopterous parasites do not appear to exert any influence in the control of these pests.
The rust mite occurs in the State as a pest of citrus, but is held in efficient check by the regular use of sulphur applied dry or in water.
Cover crops and mulch act as aids to moisture and thus help to preserve con- ditions favourable for the growth of beneficial fungi.
Nitrogenous fertilizers are used sparingly.
Only shallow tillage is given after the roots of citrus groves have taken posses- sion of the soil.
COMPARISON OF CONDITIONS IN FLORIDA WITH THOSE IN THE WEST INDIES.
It has been shown in this report that the white fly is the principal pest in Florida and that the fungi are the chief natural enemies. In the West Indies con- ditions are different; scale insects are the principal pests of citrus crops and the natural enemies include both fungi and parasitic insects. In Dominica the fungi are perhaps in greatest abundance, and this is probably largely due to the greater moisture of the atmosphere in this Island; while in Montserrat the beneficial effect is probably more equally divided between fungi and parasitic insects. In Florida the cover crops of beggar-weed and the natural growth of grass and weeds are considered to be an aid to the maintenance of the moist atmospheric conditions which are favourable to the development of the fungi, although the humidity of the atmosphere in Florida is very considerable without any such aid. In Mont- serrat the use of Bengal beans has been presumed to aid in the control of scale insects in a similar way, but it has not yet been proved that the use of this crop as a cover to lime trees greatly increased the amount of scale-attacking fungus. The experiment with limes in Montserrat quoted in a recent number of the " West Indian Bulletin" indicates that a soil cover of grass and weeds has a beneficial effect in the control of scale insects.*
About twenty years ago scale insects were the principal pests of citrus cultiva- tions in Florida, and the white fly, probably of more recent introduction than the scale insects, has increased until it holds the position of first importance in this regard. It is not possible at this time to say whether the experience in the West Indies will be similar to that in Florida, but in this connexion it is especially desirable that a careful investigation of the species of white fly occurring in the West Indies should be made, with notes on their distribution and food plants, in order that records may be available, so that from time to time in the future it
In this connexion reference is made to two papers in Vol. XI, No. 1 of the "West Indian Bulletin,"
," "Control of Scale Insects in the British West Indies by means of Fungi and Parasites," Ly F. W. South, B.A., page 1, and “Notes on Lime Cultivation," by H. A. Ballon, M.Sc., page 39.
may
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be possible to determine whether or not a decided increase of this class of pest is being brought about.
H. A. BALLOU,
Entomologist
THE FOLLOWING PUBLICATIONS are of interest in connexion with the control of white fly in Florida.
Bulletin 88, January, 1907. Bulletin 94, July, 1908.
P. H. Rolfe and H. S. Fawcett.
"White Fly Conditions in 1906." E. W. Berger.
Fungus Diseases of Scale Insects and White Fly."
Bulletin 97, February, 1909. "White Fly Studies in 1908." E. W. Berger. Report for 1907-8.
t
CE
Rep. Entom.," pp. xlviii-lxiii.
Rep. Asst. Pl. Pathol.," pp. lxiv-lxxxix. Report for 1908-9. Rep. Entom.," xxxv-xlv." Bulletin 76. "Bu. Ent., U.S. Depart. Agric."
'Fumigation for the citrus White Fly, as adapted to Florida Conditions," by A. W. Morrill, Ph.D., 1908.
The Paper by F. W. South, B.A., entitled "The control of Scale Insects in the British West Indies by means of Fungoid Parasites," which appeared in "W.I.B.." Vol. XI., p. 1, and that by H. A. Ballou, entitled "Notes on Lime Cultivation," "W.I.B.," Vol. XI., p. 39, are also of interest in this connexion since they give information as to the work that has been done in the West Indies in the use of the natural enemies of scale insects.
SIR,
The ENTOMOLOGIST to the COMMISSIONER OF AGRICULTURE.
Barbados, 19th December, 1910. I HAVE the honour to inform you that, in accordance with your letter, No. 2230,
of July 5 last, and in continuation No. 3016, of September 8, I visited, while on leave in the United States, several places of especial interest in connexion with my work.
2. I have the honour to present, herewith, reports on visits made as indicated
in the first paragraph of this letter to the following places
(a) To the Gypsy Moth Parasite Laboratory at Melrose Highlands, Massa- chusetts, and to the field work being done in Eastern Massachusetts in the control of the gypsy and brown-tail moths.
(b) To the Massachusetts Agricultural College at Amherst, Massachusetts. (c) To the United States Department of Agriculture, Washington, D.C.
(d) To the Florida Agricultural Experiment Station and certain citrus-
growing districts in the State of Florida.
3. These reports are submitted for your information, showing in what manner the time was spent for which the travelling and sustenance allowances were made. I trust also that some of them will be found to contain information of interest and value in connexion with the work of this Department.
The Imperial Commissioner of Agriculture, Barbados.
1749
DEAR Mr. READ,
No. 70.
I have, &c.,
H. A. BALLOU,
Entomologist.
SIR D. MORRIS to COLONIAL OFFICE. (Received 18 January, 1911.)
Boscombe, 16 January, 1911. I AM entirely in sympathy with the work of the Entomological Research Committee, and I hope to see it extending its efforts beyond British Tropical Africa. It is remarkable, considering the importance of entomology in the tropics, that steps had not been taken before to enter upon a systematic study of injurious insects. Europeans and natives have equally suffered from their attacks, and considerable loss has taken place among cattle and horses and other domestic animals.
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