53 



thickening of the tissues follo^^^ng the Hne of the galleries, and the 

 bark is very much cracked. The only certain sign of borer attack is 

 the emergence holes and this can be verified by shaking the stem, 

 holding it near the top, when it will probably break off in the worst 

 infested spot. Once cut away, the infested plants should be burnt 

 as quickly as possible. It is not sufficient to break off the infested 

 parts of the plant, and it is better to saw them off below the lowest 

 point of infestation. Even in this case there are frequently galleries 

 left that do not appear in the section and from which adults will 

 emerge later ; while if the main stem is cut fairly high too many lateral 

 branches are formed, the growth being green and vigorous but not 

 assisting future production. The ideal method would be to dig up 

 the plant entirely and plant a fresh one, if this were possible. After 

 June or July infested plants should be cut down to a maximum height 

 of six to eight inches above gi'ound-level, only one or two vertical 

 branches being allowed to grow. Plants so treated show promise 

 of good production, but further results must be awaited before recom- 

 mendations can be given with any certainty. In older plantations 

 it would seem that with even severer treatment good results might be 

 obtained. It is suggested that all plants should be well hilled up 

 and the trunks washed, allowing only a few vertical branches that can 

 be easily watched to grow. 



Various attempts to coat the stems of coffee plants with earth, 

 generally mixed with iron or copper sulphate, have previously been 

 made without much success, as the normal growth of the plant is 

 sufficient to break the coating, which moreover will not stand rain and 

 breaks off in flakes at the slightest shock. Tests have therefore been 

 made with other substances. The author considers it useless to 

 attempt to treat with washes trees more than four years old, unless 

 these have been thoroughly pruned. Plants treated with washes 

 would also not be entirely protected from borer attacks, as the beetle, 

 instead of ovipositing low down on the main stems, as is usually 

 the case, would do so at the base of lateral branches which could not 

 be protected. Efficient washing will, however, materially lessen the 

 damage and should be done twice during the year, once in the early 

 months and once after the heavy summer rains. Various compositions 

 of glue were tried, but did not give good results, the wash running 

 gradually off the plant to the ground and forming from the first only 

 a very thin coating which, while sufficient to prevent oviposition, 

 is not sufficient to prevent the emergence of adults. Tar and coal-tar 

 were also tried, the physical properties of the latter rendering it 

 preferable to the other substances, but even this cannot prevent the 

 adults from biting through the coating and making their e'rc.' 

 The practice of singeing the stems to destroy the eggs before hatching 

 is not recommended. The period of incubation being from 6 to 8 days 

 it would be necessary to singe the stems every sixth or seventh day to 

 produce the desired effect. Moreover, this could hardly be done 

 during the flowering period, nor during the long period of gathering the 

 crop. 



Experiments with poisons to be absorbed by the roots with a view 

 to poisoning the larvae that feed upon the plant have as yet given very 

 little success ; in many cases the plant seems to be severely injured, 



