November, 1911.] 



429 



Plant Sanitation. 



Although very rapid progress has 

 been made in recent years, both in the 

 actual knowledge ot plant diseases, and 

 in the recognition by the world at large, 

 and by Governments in particular, of 

 the importance of this, yet much more 

 work must be done, and many more men 

 must be employed, before the full 

 advantage of the scientific knowledge 

 which is even now available can be 

 obtained by agricultural communities. 



THE CONTROL OF SCALE INSECTS 

 IN THE BRITISH WEST INDIES BY 

 MEANS OF FUNGOID PARASITES. 



By F. W. South, b.a. (Cantab.), 

 Mycologist of the Staff of the Imperial 

 Department of Agriculture for the 

 West Indies, 



Part I. 

 General Account. 



(From the West Indian Bulletin, Vol. 

 XL, No. 1, 1910.) 

 Introduction. 



It has been recognized for a com- 

 paratively long time, that different 

 species of fungi are able to attack the 

 bodies of various living insects and 

 eventually cause their death ; but the 

 epidemic nature of this attack, that is 

 the hundreds of thousands of individuals 

 that may be destroyed by the fungus, 

 together with its economic importance, 

 whether beneficial or the reverse, has 

 only been recognized within the last 

 forty years. Indeed, the use of these 

 parasites in the control of various pests- 

 is of even more recent date, and cannot 

 yet be said to have attained the greatest 

 application of which it is capable. In 

 fact, it is only within the last two years 

 that the subject has received in the West 

 Indies the attention of which it is 

 worthy, and it may be directly stated, 

 that the results of the observations and 

 experiments conducted during that time 

 offer every prospect of success in con- 

 trolling scale insect attacks by means 

 of their fungoid parasites. 



The first important step in the 

 recognition of the effect of vegetable 

 parasites of insects on an economic scale 

 was the discovery of the bacterial disease 

 of silk worms by Pasteur in 1870. The 

 disease had occasioned considerable loss 

 to the silk industry in France, but the 

 recognition of its cause led to the sugges- 

 tion of measures by which it could be 

 prevented satisfactorily. 



During the last twenty-seven years, in 

 the United States q>f America, a consider- 



able amount of work has been carried 

 on having a directly opposite object, 

 namely, the reduction of the numbers of 

 various-insect pests by means of their 

 vegetable parasites, both bacterial and 

 fungoid. This work has, on the whole, 

 met with a fair measure of success, 

 more especially in the damper and milder 

 climates of the more southern States. 

 Among the insects experimented upon 

 may be mentioned the cabbage cater- 

 pillar, the chinch bug, the grasshopper, 

 and various species ot scale insects. 



The scale insects, by virtue of their 

 stationary habit, are particularly liable 

 to attack by fungi whose hyphse can 

 grow under their scales and destroy 

 their bodies. The usefulness, from an 

 economic point of view, of the fungi 

 attacking these insects has been ex- 

 ploited to the greatest extent in the 

 State of Florida where Professor 

 Rolfs, of the State Experiment Station, 

 first demonstrated in 1897 the practical 

 application of the red-headed fungus in 

 the control of the San Jose scale. 

 Subsequent work by various members of 

 the Experiment Station staff has added 

 very largely to our knowledge of such 

 fungi, and of the conditions under which 

 they may be successfully employed. 

 More recently, information as to the 

 occurrence and distribution of the 

 fungoid parasites of various scale insects 

 has been forthcoming from different 

 parts of the world, including Cuba, Porto 

 Rico, Martinique, Ceylon, South Africa 

 and Australia. 



During the last year information with 

 regard to the distribution and effect- 

 iveness of these fungi in the various 

 West Indian Islands has been collected 

 by the officers of the Imperial Depart- 

 ment of Agriculture, and the results, 

 though at present far from complete, 

 are embodied in this article, which is 

 intended as a preliminary discussion of 

 the question, and an indication of the 

 lines along which it is hoped subsequent 

 work will be conducted. The fungi at 

 present known to occur in these islands 

 are : The red-headed fungus, Sphceros- 

 tilbe coccophila, Tul. ; the white-headed 

 fungus, Ophionectria coccicola, E. and 

 E. ; the black fungus, Myriangium 

 Duriwi, Mont.; the shield scale fungus, 

 probably Cephalosporium lecanii, Zim- 

 mermann. 



General Description op the Fungi 

 pound in the West Indies. 



The following is a brief account of the 

 more superficial characters of these 

 fungi ; the fuller and more technical 

 description of them will be found in the 

 last part of this article. 



