10 
mineral oil and sulphur. The nicotine was applied as tobacco 
dust, tobacco decoction, water diluted nicotine sulphate and nico- 
tine sulphate with sulphur and an inert dust. The mineral oils 
used were kerosene and distillate emulsified with ivory soap and 
whale-oil soap. The sulphur was applied as a dust and as an 
aqueous liquid in combination with lime. All liquid appHcations 
were sprayed on to the plants with the aid of a knapsack spray 
pump and through a Vermorel nozzle. Dusts were applied with 
a patent dusting machine, except in the case of tobacco dust, 
where it was sometimes applied by hand. Each of these appli- 
cations has its individual merits, some their detractions, and none 
of them cleared out the insets entirely. I believe the tobacco 
decoction with soap gave the most satisfactory results, and I be- 
lieve it could be applied along with the iron sulphate given to the 
plants with as good results and more cheaply than when each 
would be applied separately. The aim was to kill the insects 
without burning the plant, and therefore it was necessary to es- 
tablish a minimum and maximum limit upon the concentration 
of the liquid applications. With the dusts it was necessary to 
limit the quantity placed in the heart of the plant, particularly 
during cold, wet weather, when its vitality is weakened by the 
loss of roots, in order to avoid setting up rots at this point. It 
was easily demonstrated that the immature forms could be killed 
with any one of the insecticides used, but mature individuals 
often proved resistant; and it is too obvious to be denied that 
many individuals escape the action of the insecticide at each 
application. The treatment, therefore, to be effective, must be 
continued throughout the growth of the plant, at regular intervals, 
which should be closer during the summer months than through 
the winter, because of the greater prevalence of the insects during 
the summer months, when they are favored by meteorological 
conditions. The effect, I believe, would be to keep the insects 
constantly at a low level and prevent in a measure the baneful 
influence of an accumulation of individuals so evident in old 
fields. I am also strongly of the opinion that a search for para- 
sites and predators of these two insects in the regions where they 
are supposed to be indigenous would yield results of great bene- 
fit to the industry, and if I am supported by the pineapple inter- 
ests I intend to urge the Government to undertake this much- 
needed work. We are supporting a man in Mexico at the present 
time, and if he has sufficient time at his disposal and funds are 
available when he has finished the work at present in hand, he 
will proceed to the Gulf Coast and investigate this matter, any- 
way. 
The pineapple mite or red spider is apparently another strict 
parasite. I do not know of its being found on any other plant 
than the pineapple. While its presence in the Islands was re- 
ported as far back as 1908, it is only in the last planting season 
that its injuries have come to our notice. Red spiders really do 
