CHAPTER IX 

 THE PESTS AND DISEASES OF THE CANE 



THE cultivation of the cane in all districts is one continuous struggle against 

 its pests and diseases, and the study of methods for their control is one of 

 the chief occupations of the experiment stations connected with the industry, 

 and of the Departments of Agriculture in tropical colonies. No incon- 

 siderable literature has arisen in the past thirty years, and only the fringe 

 of the subject can be touched on here. 



Abnormalities in Canes. Peculiar canes with aborted joints, with a 

 superabundance of eyes, with excessive development of woody tissue, 

 with albino leaves, and with other peculiarities, are not infrequently en- 

 countered. A peculiar case was observed in the Hawaiian Islands when 

 a seedling, H 10, with otherwise very desirable qualities, was found to have 

 developed the habit of regularly forming its upper joints without eyes. 

 Generally these peculiarities, known to botanists as chimaeras or unicums, 

 have only an academic interest. 



Weeds. The majority of the weeds that appear in cane fields also belong 

 to the grasses. Amongst the more frequent members may be mentioned 

 Bermuda grass (Cynodon dactylori), various species of Paspahim, Andropogon, 

 Panicum, Agropyron (Couch grass) and Sorghum (Johnson grass). 



Certain other specialized inhabitants of cane-growing districts have 

 been put on record. Thus in Trinidad 1 the plant Alectra brasiliensis is 

 known as the " cane killer," the roots of the weed being parasitic on the 

 roots of the cane. In India Striga lutea is common on cane lands, an allied 

 plant, Arginetia brassica, being similarly known in the Philippines. A third 

 frequent pest of the eastern tropics is the " ilang ilang " grass, Arundinacea 

 imperata. The most widely distributed and most obnoxious tropical weed 

 is the " nut grass " or " coco grass/' Cyperus sp., of which three varieties 

 are known in Java, where its local name is " teki." This sedge is an in- 

 habitant of Southern Europe, and was recognised as an introduced pest 

 in Barbados by Hughes 2 in 1750, and a few years later by Aublet 3 in Maur- 

 itius. In the former case it arrived in a pot of ornamental plants imported 

 by a Mr. Lillington. A similar pest, " knot grass," Scirpus hydra, is recorded 

 by Peterkin 4 in 1790 in St. Kitts, and is believed by him to be a visitor 

 from the Carolinas. According to Dewey, 5 the most efficacious way to eradi- 

 cate this weed is not to attack the underground tuber but to cut down the 

 stems before they set seed. 



The introduction of plants of any nature to an agricultural district is 

 attended with danger, and classical instances of the damage that can be done 

 are those connected with the Scotch thistle in Canada and the water hyacinth 



139 



