«<1 MONTHLY. IX^ 
XXII. 
COLOMBO, JULY IST, 1902. 
No. 1. 
FURTHER OBSERVATIONS ON 
HBLOPELTIS. 
Circular and AgricuUural Journal of the 
Royal Botanic Gardtns, Ceylon, June, 1902. 
T the request of the Kelani 
Valley Branch of the Ceylon 
Planters' Association, I visit- 
ed that district in March last 
and spent nearly a fortnight 
on an estate in Yatiyantota, 
where I had a favourable op- 
portunity of studying the habits of the Helopeltis 
insect and its effect upon the tea plant. 
My investigations on this occasion has shown me 
that much more work is necessary before an adequ- 
ate knowledge of the pest can be acquired. I find 
that the breeding habits of the insect vary at differ- 
ent times of the year, and will necessitate different 
modes of treatment. Before a complete scheme of 
treatment can be offered, it will be necessary to have 
more accurate observations of the insect throughout 
the year, and from different elevations and local- 
ies. At the end of the present paper I have suggest- 
ed a few ways in which those interested in the 
matter could materially assist my work. 
1 now append the results of my investigations and 
experiments. 
Having previously, on several occasions seen the 
pest at the height of its activity, I endeavoured to 
time my present visit to enable me to study the 
insect at the period of its least activity. 
There has been a general idea that Helopeltis 
completely disappears at certain x^eriods. Opinion 
of local observers varies on this point. Some Super- 
intendents insist that the disappearance is * com- 
plete ; while others maintain that living specimens 
of the insect may be found, by careful searching, 
at any time. IMy own observations lead me to 
favour the latter supposition. There is no doubt, 
however, that there are usually two periods of com- 
parative inactivity : the first, from the middle of 
March to the middle of June ; the second during the 
months of September, October, and November. 
These periods vary both in duration and intensity. 
In 1901 reports from an estate near Dehiowita 
showed very little decrease of activity during the 
above-mentioned periods. In other years affected 
fields have apparently enjoyed periods of complete 
freedom ; though it is almost certain that some of 
the insects must remain upon the bushes, possibly 
in a partially dormant condition. The conditions 
(climatic or other) that govern the periodicity of 
attack have not yet Deeu properly determined. 
Rainfall does not appear to be an important factor, 
as the two periods of greatest activity coincide, the 
one with a season of comparative drought (January, 
March), the other with a time of hea\'y rains (July, 
August) . Wind has been suggested as a cause for the 
decrease of the pest, but I find that strong wind 
prevails only at one of these periods. 
At the time of my present visit the pest was 
evidently on the decline, iwo torn, but the fields 
showed signs of recent severe attack. 
My first experiment was to try the effect »f a power- 
ful acetylene gas light. An apparatus fsupplied by 
Mr. E. B. Creasy, fitted with a burner of 50 candle 
power, was used for the purpose. Ths lamp was set 
up in a hollow where there was ample evidence of 
recent attack, and where specimens of the insects 
were being daily caistured by hand. A dark still 
night was chosen, and all conditions were in favour 
of the experiment. The burner of the lamp projec- 
ted from the centre of a basin filled with kerosine and 
water. Insects attracted by the light fell into the 
basin and were held and killed by the floating film 
of oil. The lamp was lit at 6.30 p.m., about half 
an hour^ after sunset, and remained burning until 
daylight next morning, when the surface of the 
liquid was found to be covered with a floating mass 
of miscellaneous insects. The work of sorting out 
and esamiuing tke cat9li occupied the whole of the 
