safety where they pour vituperation on the helpless Gardens’ staff. The office 
shot gun was found to have bent barrels, and to this defect is attributed a 
major share of ineffective action. A number of plants particularly on Lawn 
A, E, F, H and L have been badly damaged by monkeys. Young palm seed- 
lings on Lawn W have had to be caged in wire netting. 
66. The reduction in incidence of rhinoceros beetle ( Oryctes rhinoceros ) 
reported in the 1959 Report has been maintained, but constant watch on com- 
post heaps is necessary. Perhaps the nicotine content of small quantities of 
impounded and confiscated tobacco received through the Customs and Excise 
Department which has been mixed into compost heaps may help to reduce 
suitable nursery areas for larvae. 
67. The red stripe weevil (Rhyncophorus ferruginea ) remains a problem. 
Nine palms were killed by this insect during the year: Verschaffeltia splendida ; 
Licuala grcmdis; Phoenix daetylifera; 3 Oreodoxa oleracea; 2 Sabal mexicana 
and Borassus machadonis. Control of this beetle presents greater difficulties 
than of the rhinoceros beetle. It is usually the taller palms that are attacked 
and the crown does not show any symptom till after the fatal damage has 
been done. 
68. An attack of banana stem borers (Coleoptera) was discovered in a 
planting of banana varieties of Lawn T. The Commonwealth Institute of Ento- 
mology, London, determined the major damage as done by Odoiporus longi- 
collis , and the minor pest as Polytus mellerborgi, recorded from the Philippines 
and Fiji, but only once previously from Malaya. The outbreak was success- 
fully controlled by dusting the banana pseudostems with Agrocide 3. 
69. An unidentified animal in the Lake continues to graze down the 
Nymphea preventing re-establishment of the very decorative cover these plants 
gave to the Lake a few years back. Colonies of Nymphaea have been growing 
behind wire netting protection and whatever it is that likes to eat Nymphaea 
roots is clearly too large to pass through the 2 inch mesh of the netting. The 
turtles ( Trionyx cartilagineus ) in the Lake are suspect, but this hypothesis is 
unfortunately in conflict with zoological opinion which has it that these 
animals are wholely carnivorous. 
70. Dioscorea sansibarensis, which was introduced to the Gardens some 
45 years ago for the then Director’s work on the genus Dioscorea , has per- 
sisted as a rampant, smothering weed around the perimeter of the Gardens 
but has never apparently spread further afield. In the past four years there has 
been very appreciable increase in its abundance, and steps have had to be 
taken to eradicate it. This feature of vigorous colonisation of a locality with- 
out spreading from it is an interesting aspect of plant invasion ecology. It has 
a close parallel in the animal world in Malaya in the Ceylon Crows at Klang 
and more recently in the Singapore harbour area. In marked contrast is the 
spread of other introduced plants and animals such as Cordia cylindristachya , 
which will soon be a common waste-land shrub throughout most of Malaya, 
and the Giant African snail, Achatina fulica, long since spread from Singapore 
and Penang over the whole country in the lowlands of Malaya. 
XIX. HORTICULTURAL EXCHANGE 
71. Seed and plant exchange with other botanical organisations abroad 
was again an important aspect of the work of the Horticultural Division. Two 
persons were engaged full time on seed and plant collection in fulfilment of 
requests. Owing to the difficulty of storing seed in Singapore’s humid climate 
14 
