18 
of one-tenth inch. Whilst the Aoroa is growing the leaf con- 
tinues to rot; it does not dry up as it does when only attacked 4 ee 
Peronospora, but the plant tetkin a pee deal of moisture, an 
thoroughly tee Fs rise to a most offensive smell. The bulb is ics 
sometimes affec 
he dense Pinel colour of this fungus is so much more conspicuous 
than the whitish powder of the Peronospora that it is sometimes stated 
to attack onion crops which have not suffered from the Peronospora 
ie oser observation, however, shows that it invariably follows the 
ungus. 
It is the Peronospora which does the great harm to a onion crops, 
and the Macrosporium is only a sequel to it. Hence all remedial 
measures must be directed against the former, for with its vexteeriiinstidin 
the Macrosporium will disappear. 
Sect. VI.—Insects. 
There is a very minute insect, a species of Thrips, which occurs 
occasionally, though not in any great numbers, at the top of the bulb 
in the angles between the peaves of the full-grown onion plant. It 
upon substance of the onion n leaf, The FAN ee has a muc 
rs 
of wings. In this stage it is very much less common in the leaf than 
in the larval condition. 
This insect was found in comparatively few farms, and then in 
very limited numbers. It does not burrow tbrough the leaf, and 
appears to cause very little damage to the onion plant. ld, 
however, the numbers increase largely, or sopua it appear upon the 
young seedlings, it might be the cause of seri : 
A simple way of getting rid of it is = sera or ‘spray the i i 
plants with a solution of iron sulphate, such as was recommended i 
Sect. IV. iii. This would more BEP prove effective in the case 
of the onion, because some of the solution would collect in the angles of 
the age where the insect most commonly occurs. 
The onion fly, Anthomyia apan, whose maggots do much harm b 
eating ieee the bulb of the onion, ours so rarely in Bermuda, that 
it hardly calls snes remark in “this report. I only met with a single 
instance of it d my stay in the Colony: 
Tn case, aa, that it Jould at any fature time prove troublesome, 
it is worth mentioning here that Miss Ormerod has successfully dealt 
with this cak by ptite“ the bulbs with a thin layer of earth, so that 
they no longer stand o the und. is in no way injures the 
plant, and gatens the fly getting at the bulb to lay its eggs. 
Sect. VIJ.—SummMary. 
1. The onion disease is caused by a fungus Peronospora Schleideniana, 
which lives parasitically upon the leaf of ans onion plant. 
2, The atmospheric conditions which favour the progress of the disease 
are heavy dews or rains followed by warm, moist, calm weather, and the 
bsence of direct sunshine and cold winds. In favourable weather the 
progress of the Possa i is very rapid. 
3. The- fan gus. lives in the tissues of the leaf, choking up the 
passages and eaae the nutritive fluid formed in the cells, iis 
