-2C. 



THE AGRICULTURAL NEWS. 



Jam AKV -20. 1918. 



INSECT NOTES. 



INSECT PESTS IN UGANDA. 

 The Annual Kepott ot the Department of Agriculture 

 of Uganda, for the year ended March .31, 1917, contains an 

 interesting record of the progress of agriculture in the 

 Protectorate during the above period, and since many of the 

 crops grown in Uganda are similar to those grown in the 

 Wtst Indies, certain points of interest connected with these 

 crops will be referred to in this number of the Ayricuhund 

 A'ti'-s. The following notes dealing with those insects which 

 are of special importance to readers in these islands are 

 taken from the report of the Government Entomologist, 

 Mr. C. C. Gowdey, and are arranged under their respective 

 Lost plants. 



COFFEE. This crop is attacked by sixteen species of 

 scale insects, most of which are of no special economic 

 importance. The most important of these is the mealybug 

 Pirvljcoccui citri, Risso, which occurs almost everywhere in 

 tropical regions. This species not only clusters on the coffee 

 flowers and newly set fruit, sometimes cau.sing these to drop, 

 but also infests the foliage and the roots. Mr. Gowdey gives 

 a brief account of the life-cycle of the insect, as follows: The 

 eggs are laid on the fruit, twigs, under the loose bark on the 

 srem, and roots. They are enclosed in light cottony 

 material in clusters varying from 300 to 500 in number. 

 The period of incubation is about eight days. The 

 newly hatched larvae are light yellow in colour, and at first 

 are devoid of any waxy covering, and henc e it is at this stage 

 that remedial measures would be the most effective. The 

 larvae moult three times, aLout fifteen days elapsing between 

 each moult. Egg-laying begins about ten days after the 

 final moult— that is after the adult .stage is reached— and 

 death soon follows oviposition.' The other species of scale 

 insect- mentioned under coffee, which also occur in the 

 AVest Indie?, though not always on coffee, are Pseudor'.cntK 

 v.'rgafvs, Cfcctis "iridis, .Saif tia heiuisphaeri'^a, S. nigrn. 

 Seler.atpidus articuUiiuf. and /cs/inaspi" longiroHrif. 



The coffee leaf-miner, {Lrwoplem [Cemii'StOmo] 

 rr/ettla), Staint., has recently appeared as a pest 

 in Uganda, but is at pre.-ent confined to one district 

 This insect is a minute, silvery, white moth, which lays its. 

 eggB on the leaves. The larva, on hatching, bores into the 

 leaf, and feeds between the upper and lower surfaces. It 

 eventually causes a large brownish blotch due to the drying 

 of the upper surface of the leaf, and badly infested leaves 

 often drop. The larva becomes full grown in about two 

 weeks, and, crawling out, |>upates on the outside of the leaf. 

 The moth emerges in about a v eek. Mr. f Jowdey finds that the 

 only control measure is the 'cllection of the infested leaves, 

 those that have fallen as well as those remaining on the trees.' 

 It may be mentioned that this leaf-miner is abundant on 

 coffee in Porto I'.ico and Cuha, but in both of these islands 

 the larva is parasitized to some extent by minute hymcn- 

 optera. 



COTTON. Siwcies of cotton stainers, Dpflerrun spp.and 

 Orucaraenus spp., are mentioned as being abundant on cot- 



ton. The species of Dysdercus in the West Indies are now 

 known to be disseminators of certain internal boll diseases, 

 which are apparently not present in Uganda. These boll 

 diseases are the principal cause of the staining of the lint 

 which was formerly thought to be due to excrement deposit- 

 ed by the bugs. In this connexion it may be mentioned 

 that measures are now being taken in some of the cotton- 

 growing islands of the Lesser Antilles to control the stainers 

 by the eradication of their wild food-plants, and this method 

 has so far proved very successful in St. Vincent. 



EUBBEi:? Ceara'an'd Para rubber trees were badly in- 

 fested with the bourbon scaIs {As2}idintus destructor, Sign), 

 and in several cases the Ceara trees were killed. 



FRUIT TKEEs A Ust is given under their respective 

 host plants of the various insects attacking fruit trees. 

 Among the insects attacking orange trees are the or.inge but- 

 terfly (Papi/io dniiodocus, Esp), and the fruit fly {Ceraiitis 

 capitata). Caterpillars of the butterfly genus Papilio occur 

 as pests of the leaves of citrus trees in many parts of the 

 world, and sometimes defoliate the trees. Two species are 

 recorded from Cub;-., namely P. androLenmn and P. t/i'xis. 

 In F>ritish Guiana the species P. anrkii'Htdes sometimes 

 defoliates orange trees, but insects belonging to this genus are 

 not known to be injurious to orange trees in the Lesser 

 Antilles. 



The fruit fly mentioned above is the Mtditerraneaa 

 fruit fly, which is a serious pest in some parts of the world. 

 Although this species is not known to occur in the West 

 Indies, it has been established in IJermuda for many years 

 {Agricultural Neu's, Vol. XV, p. 10). An account of this fly, 

 as it occurs in Uganda, was given by Mr. Gowdey in his 

 Annual Keport for 1912-13, and was reproduced in the .^Ijfri- 

 cM/;«rai A>*f,s Vol. XIII, p. 122. 



Amang the scale insects mentioned as occurring on fruit 

 trees are Lepidosap/its gloveri and /.. citricola on orange, 

 and Aspidiotus destructor on mango, guava, and banana. 



The shade tree (Gliricidia niaciilatujia mentioned as 

 leing seriously attacked by the scale insects, Pieudococcus 

 citri and Coccus limgulus, and by the aphid Tocoptera otffeae. 

 This plant is sometimes used as a shade tree or as a wind- 

 break in cacao and lime orchards in the Lesser Antilles, but 

 so far has been remarkably free from jiests. 



In conclusion, Mr. Gowdey gives a list of some of the 

 l)arasitic and predaceous insects which he has succeeded in 

 breeding, and this list shows that many of the crop pests in 

 I'ganda have their own particular insect enemies. 



MOTH 



BORERS OF SUGAR-CANE IN 

 MAURITIUS. 



In view of the importance of the moth borer (Diatraeii 

 saccfiriralis) wherever sugarcane is grown in the West 

 Indies, it may be of interest to give a short account of the 

 moth borers attacking sugar-cane in Mauritius. These pest.H 

 have been studied by M. d'Emnierez de Gharmoy, the 

 Entomologist, and the results of his work have been pub- 

 lished as Jiultctin A'o. ■'•, of the Mauritius Department of 

 Agriculture. 



There are four species of moth borers which attack 

 sugar cane in Mauritius, and these are known respectively 

 as the pink borer {Siuimia ruteria, Stoll.), the spotted borer 

 (Diiitracn succharipliaga, Uojer), the white borer (Grapholita 

 tcliistaceana), and the brown borer (Alwifa saccUari, Kojer). 



The pink borer is distributed throughout the island and 

 is known in many sugar-growing countries, but has not been 

 recorded from the West indies. It is very common on 

 many graminaceous weeds, on some of which it lays its eggs 



