KKPORT ON ECONOMIC ENTOMOLOGY 
245 
boxes on the surface, and done my best to get them eaten by white ants — but after periods 
of from seven to eleven months, all treated wood, in or on the ground, is absolutely uutouchetl. 
Solignum can now be olitained locally in Khartoum, or from the makers, Messrs. 
Major and Co., Ltd., Hull. 
Green Willesden canvas is also proof against wliite ants. 
The S hIp w o k m 
Teredo 
The shipworm — Teredo —is responsible for a considerable amount of damage to 
submerged timber in the harbour at Port Sudan. 
This bivalve is a well-known pest in many countries. In Vancouver, it is said to have 
reduced a wooden pile supporting a jiier to a mere spongework of wood in the short space of 
eighteen months,' while in Holland its ravages have led to the expenditure of many 
millions sterling. 
It tunnels in the wood, lining its burrows with a shelly deposit. 
Treventim; taeasures. — As yet, no really satisfactory preventive has been discovered, 
though many have been tried. 
Closely covering timber with sheet copjier to well above high-water niai'k was found to 
be prohibitive on account of its cost. 
Closely covering the surface of the timber with large headed iron nails — which have 
quickly rusted into a solid mass — has been extensively tried, but the crust so formed has 
sooner or later been broken and the shipworm gained entry. 
Timher impregnated with creosote oil — Bethell’s process—will resist the teredo for 
periods varying from fifteen to twenty-five years. The quantity of oil injected per cubic 
foot varies from 12 lb. to 20 lb. with the temperature of the water and the density of 
the wood. 
Among the few timbers that arc, to a certain extent, resistant to the attack of the 
shipworm are teak, greenheart — Necandra roduci — and North Borneo ironwood. 
Fuxuoij) Pests 
Cotton A n t h k .y c n o s e 
( ■olletotrichiiin yossypH, Southworth 
This fungus is responsible for a certain number of the cotton bolls which die before 
attaining maturity. 
I have only noticed anthracnose on the bolls, but it may also attack seedlings and the 
stems and loaves of mature plants. In the two latter situations, however, it does not do 
much harm and probably exists mainly as a saprophyte. 
A boll attacked by this disease shows small we't-looking depressed areas, frequently 
with reddish margins. These areas increase in size, and at the same time the development 
of that part of the boll affected is arrested. If only one carpel shows signs of attack, the 
others will continue to grow and the boll becomes one-sided. Usually, the whole boll 
withers and dies unopened or only partially opened. 
In the case of young seedlings, the fungus attacks either the stem or the cotyledons 
and the plant soon succumbs. 
.\nthracnose is generally distributed on seed, the spores being carried about entangled 
in the lint that adheres to the seed coat. Care should be taken, tluu-efore, not to use for 
sowing-seed that which has been saved from an infected cro]). 
' Shipley, Cumbruhjr Sutural Jlisluri/, Zmluyij, pp. ’220, 221. 
A marine pest 
Fungoid pests 
