ENCLOSURE TO PART 1V. as
PINK BOLL WORMS. ALTERNATIVE FOOD-PLANTS.
Mr. RITCHIE stated that as far as was known, the only
alternative food-plant in Tanganyika was okra (H. esculentus).
Mr. KIRKPATRICK said that in Egypt the known alternative
food plants were Hibiscus esculentus, Hibiscus cannabinus, hollyhocks
 and, possibly, other Malvace®, but more research on these
lines was necessary.
It was agreed: —
That the whole question of alternative food-plants was
uncertain and open to investigation.
APION.
BARON SURCOUF read the following paper on Apion Armipes
(referred to in the Agenda as T.C.(C)E.& M.7):—
In September, 1925, I inspected the cotton crops in the district
of Zambezia. One of the pests noticed was Apion armipes, Wagner,
which occurred chiefly on cotton cultivated by natives, though it
was also abundant on cotton grown under the direct control of the
Mozambique Industrial and Commercial Company.
The damage caused by this species was considerable, hundreds
of hectares of cotton bearing no crops of any appreciable value.
The adult weevils are found in the cotton flowers, on the petals of
which they feed. The females oviposit on the axils of the leaves,
three or four eggs being laid at a time: The larve on hatching
penetrate the tissue of the young stem, in which they live. A
vigorous plant, when attacked near the growing point, develops
secondary growth in the neighbourhood of the attacked region: weak
plants, however, die.
With the aid of a lens, it could be seen that many of the
Apion larvee were parasitised by a small Hymenopteron. The
larvee of this parasite when full-fed, leave the dead Apion larva, and
emerge from the stem of the plant, on the outside of which they
form elongated white silk cocoons, of which there may be at least
a dozen from each host larva.
By collecting these cocoons, I succeeded in obtaining about
250 living parasites which were liberated in the district of Canchiche,
with the result that the Apion in that neighbourhood almost completely
disappeared.
In my opinion the best methods to be employed for the control
of the Apion are the breeding and liberation of this parasite; and
the destruction of the alternative host plants of the Apion in the
vicinity of cotton plantations.
~ BARON SURCOUF stated that he had found thousands of
Apion on cotton in Portuguese East Africa, but had not discovered
it on any other plant.
Mr. SMEE said that Apion was determined in Nyasaland
about 1909, when it was reported to have been serious. It was still
present there but he had not noticed that it did much damage to
cotton, as it appeared late in the season and the damage done was
negligible.

QE