The Tobacco Slug. 29 



great numbers, and, therefore, not drawing attention. In 1919 it 

 was further reported by the Magistrate of Paulpietersburg, Natal, 

 .and its presence in the adjoining district of Wakkerstroom, and in 

 Swaziland, became known. 



In 1920 it was located by officers of the Division of Entomology 

 near Bathurst, and also near East London, Cape Province, and at 

 Verulam and Umkomaas, Natal. 



Farmers and others who may observe the insect in new localities, 

 whether feeding on tobacco or other plants, are requested to commu- 

 nicate with the Division of Entomology. 



Nature of Injury. 



The damage done to tobacco in the field is thus described by 

 Mr. G. C. Haines, of this Division : " At first the lower leaves of 

 the plant are attacked. The eggs are laid almost invariably on the 

 under-sides of the leaves in close masses of 15 to about 40. The 

 slugs, on hatching, start to feed near the old egg mass, feeding in an 

 enlarging circle, and lined up side by side. At first tbey are 

 gregarious and attack only the lower surface of the leaf. Later 

 tliey separate and eat large ragged holes through the leaf. If many 

 larvae are present on a leaf in a short time only the midrib and a 

 few large side ribs will be left. In the seed-beds the mode of attack 

 is similar, the centre plants, which are close together, being attacked 

 first. In some seed-beds half the plants were destroyed, dozens of 

 larvae being found on every leaf, and I was told that, at other places, 

 the plants, both in the seed-beds and in the fields, were completely 

 destroyed." Mr. Haines was informed that tobacco in the curing- 

 sheds, and even in the bales, was also attacked; but, as was suspected 

 by him, and afterwards confirmed by Mr. J. C. Faure, of the Divi- 

 sion, this only takes jdace whilst the tobacco is still green. 



The method of harvesting tobacco in the Piet Retief District is to 

 cut the whole plant and hang it up in the shed to dry. The drying 

 takes more than a month, and there is time for larvae brought in on 

 the plants to develop to maturity. The damage done in sheds is very 

 great, and, perhaps, relatively greater than in the field, as the 

 insects are better protected from natural enemies and unfavourable 

 climatic conditions. Such damage can be prevented by other methods 

 ■of drying the tobacco, but it is thought that the damage in the shed 

 will be trifling if the pest is properly controlled in the" field. 



Description^ of Stages. 



The Egg. — The eggs are oval in shape, about one-twentieth of 

 an inch long and iialf of that in width. They are dirty white to 

 yellow in colour, the latter colour being more prevalent. They are 

 covered with slime, which does not dry but remains a long time 

 sticky, though it may change to a dark colour. In appearance the 

 •eggs somewhat resemble those of ladybirds, but they often show black 

 tips. This may be due to either of two causes. Sometimes there is 

 at the tip a little excess of the slime with which the eggs are covered, 

 and, when this turns dark, the tips appear black. Then, again, when 

 the eggs are ready to hatch, the black heads of the larvae inside show 

 through the shells at the tips. 



The Slug and Cocoon. — When hatched the slug-like larva is 

 about as long as the egg from which it emerged. It is also sticky, 

 though it has not yet a visible slime upon it. It is greenish in 



