2. ENCLOSURE TO PART 1V. 
~ We seem to be somewhat in the dark as to which of the fungi and 
‘bacteria are true wound parasites, and which merely saphrophutes, 
although several can no doubt be relegated to the latter category. 
The position appears to be that there is a fungus and bacterial complex 
associated with certain forms of internal boll disease, distinct from 
the diseases caused by Bacillus malvacearum and Phytophthora (Soft 
Rot), and that so far experiment indicates that this complex is 
dependent upon a breach in the carpel to obtain access to the interior 
of the boll. The composition of the complex appears, however, to be 
far from uniform. Furthermore, no definite distinction appears to 
have been established between lint staining and obvious boll rot, and 
the two lesions are commonly described under the same heading. 
All this is unsatisfactory in one particular, namely that it 
commonly leaves the investigator without a means of identifying a 
given form of staining or discoloration in a specific manner. 
To give an example, the small plots of cotton at the Agricultural 
Experiment Station, Salisbury, show practically 100 per cent. stained 
lint this season, and on one at least of these plots, which has been 
under close observation, the agency of Dysdercus or other sucking 
insects large enough to pierce through the carpel may, it is thought, 
definitely be ruled out. Moreover, the stained bolls in most cases 
afford no indication whatsoever of any perforation of the carpel nor 
does the distribution of the stain show any relation to a hypothetical 
puncture. It is located at the bases of the locks, all of which are 
involved. The lint is adherent to the carpels at the base and a 
portion tends to remain behind when the lint is picked in the ordinary 
way. Apart from this the bolls have not opened properly, and most 
of the lint in the opened bolls remains compacted. ; 
The crop has been very slow in maturing, the elevation at 
Salisbury being probably too high for successful cotton culture in most 
seasons. On general considerations one would be inclined to attribute 
the condition of the cotton to physiological causes, but the staining 
answers well to the description of this trouble as shown to be 
transmitted by Dysdercus. It is here that the lack of a means of 
specific identification of the disease transmitted by Dysdercus is felt. 
Reports throughout the Colony are to the effect that staining is 
extremely prevalent this season, and heavy losses are anticipated. 
Dysdercus spp. have certainly been very prevalent on many farms, 
and in many cases have clearly attacked the stained bolls previous to 
opening. At the same time the season has been an abnormally wet 
one, and the plants have suffered to a considerable extent on this 
account. In the light of experience at Salisbury caution appears to 
be indicated in attributing all this staining to Dusdercus. 
It is also noted that Mr. H. C. Sampson in his report to the 
Empire Cotton Growing Corporation, 1922, describes lint staining in 
Nyasaland in a way which i$ in agreement with experience in Southern 
Rhodesia, and does not suggest Dysdercus as the cause in all cases. 
The influence of the season in reference to the trouble is also 
emphasized by Mr. Sampson. Moreover, the connection between 
Dysdercus and boll diseases does not appear to be clearly recognised in 
the South African Union, if one may judge by Mr. G. C. Haines’ 
paper read before the conference of entomologists at Pretoria last 
year. Dysdercus in point of fact has been regarded as a minor pest 
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