2 ENCLOSURE TO PART 1V.
- Mr. RITCHIE said that Apion zanthostylum was found in
Tanganyika but only in the Morogoro area. The first generation
attacked the base of the young cotton and might kill the plants.
Further generations breed at the junction of the branches and under
the boll, causing premature ripening and consequent weakening
and shortening of the staple. arly in 1922 they realised Apion could
be a serious potential pest on cotton, and 159 of the trees on the
experimental station at Morogoro died early in the season from attack
at the base. After that time strict measures were taken to ensure
that all cotton was properly uprooted. Apion was still found but he
had not regarded its effects as serious. Parasitism by a braconid was
known but he would not rely on control by parasite. It had been
found in Tanganyika that uprooting and burning was an entirely
satisfactory method of dealing with the pest.
Mr. HARDENBERG from experience with this insect in the
district of Quilimane, considered that Apion was a potential pest of
very great importance; and was of the opinion that infestation in
cotton plantations originated outside the cotton fields and gradually
spread. He had noticed that some of the pupz contained parasites
but had no information as to their identification.
Tt was agreed that Baron Surcouf’s paper should be incorporated
in the Report, and that a statement should be added to the effect: —
That there is danger of Apion becoming a serious pest if
uprooting and burning is not resorted to, but that in Tanganyika
uprooting and burning has been found to be entirely successful.
SUDAN BOLL WORM (DIPAROPSIS CASTANEA.)
DISTRIBUTION.
This pest has not yet been reported from Uganda (Hargreaves),
Tanganyika (Ritchie), or Kenya (Anderson). It is a serious pest in
Nyasaland (Smee), and in Portuguese Fast Africa (Hardenberg): it is
also known to be present in the Belgian Congo: it occurs over the
whole of the cotton areas in South Africa, except in parts of the Cape
Province (Haines).
Mr. HARDENBERG said that in Mozambique it occurred where
cotton was grown. It was a serious pest and the worst on cotton, and
was responsible for 809% of Toss of crop.
Mr. SMEE stated that it was widely distributed in Nyasaland,
where it was the most serious pest and the main limitation of cotton
culture.
Mr. RITCHIE said that one record was extant from Tanganyika :
this was from the extreme southern corner of the Territory, bordering
on Nyasaland, in 1925 when cotton growing was attempted there for
the first time since the war.
Wirp Foop-PLANTS.
Mr. HAINES (contributed). The Sudan Boll Worm is found on
cultivated cotton and wild cotton (Gossypium spp.) and on a wild
Malvaceous plant (sp. undet.). This last food-plant was found by F.
S. Parsons at Magut, Zululand.
Mr. SMEE said that in Nyasaland it had only been found on
cotton. except for one record on Thespesia.

+24