558 



Measures that have been found successful in combating the hoppers 

 in the past and recommendations for future control include the col- 

 lection of egg-masses from the leaves or rubbish at the time of planting 

 the cane setts ; these are easily distinguishable owing to the thread- 

 like white covering, and when collected, should be put in wide-mouthed 

 earthen vessels, the tops of which are tied over mth cheese-cloth 

 having meshes sufficiently wide to allow the parasites to escape ; such 

 collections should be continued from August to December. During 

 March, April and May, if any n}'TQphs and adults are found on the 

 newly-planted as well as the ratoon canes, they should be bagged 

 with hand-iiets or field-bags, several types of which are illustrated. 

 When infestation is particularly severe, the canes should be sprayed : 

 3 pints of crude oil emulsion to 4 gals, w^ater was found sufficient 

 to prevent the emergence of the nymphs ; while i pint crude oil 

 emulsion and 1 pint sanitary fluid to 4 gals, water is a good spray 

 for nymphs and adults. A first spraying was given in November 

 and was followed by a second application. The numbers of nymphs 

 and adults were considerably reduced by this method, but the leaves 

 of certain varieties of cane were more or less affected. As leaf-hoppers 

 are found to damage broad-leaved varieties of cane more than the 

 narrow-leaved ones, where cane is to be grown under irrigation for a 

 series of years and where injurious species of Pyrilla are abundant, 

 it would be better to give jDreference to the latter varieties for two 

 consecutive years at least. 



Smyth (E. G.). The White Grubs injuring Sugar-cane in Porto Rico. 

 I. Life-histories of May-beetles (continued). — Jl. Dept. Agric, 

 Porto Rico, i, no. 3, Julv 1917, pp. 141-169. [Received 18th 

 October 1917.] 



This paper is the second of a series, the first of which has already 

 been dealt with [see this Review, Ser. A, v, p. 410]. As a result of 

 investigations into the behaviour of the green muscardiue fimgus, 

 Metarrhitium anisopliae, in its attack on Lachnosterna {Phyllophaga) 

 vanditiei, the following conclusions in regard to its effect upon ^lay- 

 beetles have been reached : the fungus appears to be transmissible 

 between adults ; in the case of grubs it is evident that infection takes 

 place through the soil ; other insects infected with this fungus outside 

 the insectary include Aj)hodins sp., Canthon sp., Strategus tifanus, 

 Ligyrus tumuhsus and Phytalus insularis; the disease alone is 

 sufficient to kill white grubs, though infection is sometimes aggravated 

 by previous attack of the grub by mites or bacterial disease ; a rather 

 long period of infection, generally accompanied by lengthening of the 

 instar in which the disease is contracted, usually precedes death. A 

 very h'gh mortality among the grubs in the experimental boxes was 

 apparently caused by a bacterial disease, beheved to be identical with 

 Micrcccccus nignfaciens [see this Review, Ser. A, ii, p. 639]. Only 

 the larval stage is attacked, and while the majority of the grubs in the 

 boxes ^ ere infected, none collected out of doors were affected by this 

 disease, although they toon contracted it after being placed in the 

 boxes, owing piolf.b.y to the character of the soil, the degree of 

 hum:.dity, or the tonfiUement that predisposed them to disease, which 

 was ccntiact€d titer tome mechanical injury. This bacterial disease 



