December, 1908. j 



537 



Edible Products. 



Very little is known as to the effect 

 of artificial manures on lime plantations, 

 A series of experiment plots to which 

 various special manures have been 

 applied is under observation, and inter- 

 esting information should be available 

 in the course of a few years. 



Too much stress cannot be laid upon 

 the good results that accrue from appli- 

 cations of pen manures or of mulch, for 

 the appearance of many lime plantations 

 has, in a short time, been completely 

 changed by attention to this operation. 

 Most planters are now fully alive to the 

 benefits to be derived from attention to 

 the humus question. 



The life of a lime plantation in Domi- 

 nica has not yet been determined. Well- 

 kept fields of limes, planted over thirty 

 years ago, are still in good condition and 

 yield good crops, and they appear likely 

 to remain profitable for many years to 

 come. 



Pests and Diseases. 



The lime tree has numerous enemies, 

 and as the area under lime cultivation 

 enlarges, they are also likely to increase. 

 The attitude of the planter should be 

 one of constant watchfulness, as the 

 time has come when he can no longer 

 depend on the heavy rainfall, and on 

 parasites of the scales to keep his lime 

 trees free from scale insects. The scale 

 that has caused the most damage to lime 

 cultivation up to the present is the 

 mussel scale (Mytilaspis citricola), which 

 inflicted great havoc in plantations dur- 

 ing 1902. Another scale that is preval- 

 ent is the orange snow scale (Chionas- 

 pis citri). The latter is almost entirely 

 confined to the trunks and thick 

 branches of the tree, and is best dealt 

 with by painting the parts affected with 

 any of the mixtures recommended by 

 the Imperial Department of Agriculture. 



Probably the most serious enemy of 

 the lime plant at present is Lecanium 

 viride, a scale that is increasing rapidly 

 on lime estates in Dominica. Its attacks 

 are always accompanied with ' black 

 blight.' 



Other scales present on lime trees are 

 the West Indian red scale (Aspidiotus 

 articulatus), and the brown shield scale 

 {Lecanium hemisphcericum). These, how- 

 ever, have done no harm to speak of 

 up to the present. 



Scale insects may be present on a 

 plantation for years, and do so little 

 harm that their presence is unnoticed by 

 the planter. Occasionally conditions are 

 such as to favour their rapid increase, 

 and the planter sees his trees attacked 

 by blight, which causes heavy loss, 

 68 



When the parasitic enemies of the scales 

 fail to keep them in check, spraying 

 must be resorted to. Pull particulars as 

 to scale insects and to spraying outfits 

 and mixtures may be found in the 

 Pamphlets Nos. 5, 7, and 22 issued by the 

 Imperial Department of Agriculture, 

 entitled ' General Treatment of Insect 

 Pests,' second Edition, and 'Scale Insects 

 of the Lesser Antilles,' Parts I and II 

 respectively. 



In the early days of lime planting no 

 thought was given to possible attacks of 

 scale insects. Trees were planted close 

 together and little attention was given 

 to straight lining. In old plantations, 

 therefore, in the majority of instances, 

 it is almost impossible to carry on effec- 

 tive spraying. The young planter should 

 bear this matter in mind, and should 

 plant his fields so that spraying may be 

 thoroughly done should occasion demand 

 it. 



The lime tree bark borer (Deptostylus 

 prcemorsus) is another pest that has 

 done considerable injury to lime trees. 

 To combat it, the removal of dead 

 branches and dead bark is recommended, 

 the probing of the tunnels in the wood 

 with wire to kill the larvae, and the 

 application to the trunk of a protective 

 material made of whale oil soap, carbolic 

 acid, and clay. It is noticeable that 

 the attacks of borers are more prevalent 

 on wet, heavy soils, than on light soils. 

 Possibly improved drainage might assist 

 in keeping down this pest. 



A good deal of fungus disease is 

 noticeable on some of the trees, in many 

 of the old plantations. Bracket fungi 

 such as Fomes lucidus and Poly sticks 

 hirsutus are not uncommon. The latter 

 has been found on living trees, but it 

 is questionable whether the former may 

 be regarded as parasitic in habit. The 

 presence of fungus disease is the result 

 of neglect. Were pruning properly done, 

 all dead branches carefully removed, 

 all wounds dressed with Bordeaux mix- 

 ture, and afterwards coated with tar, 

 these fungi would be banished from 

 lime fields. Their continued presence 

 lowers the vitality of lime trees and 

 reduces the crop. During recent years, a 

 fungus, probably a species of Alternaria, 

 has been noticed on the leaves of lime 

 trees growing on stiff soils in wet 

 districts. This fungus causes greyish 

 to brown spots on the leaves, but has 

 done no appreciable harm up to the 

 present time. Its appearance and habit 

 should be noted. If it becomes at all 

 prevalent, destruction of all diseased 

 leaves should be practised, and spraying 

 with Bordeaux mixture resorted to. 

 Pamphlet No. 17 entitled ' General Treat- 



