444 



short time in cultivation and it is as yet uncertain whether it should 

 be kept out of the plantations. The effect of " rampassen " operations 

 on Helopeltis [see this Review, Ser, A, Vol. I., p. 57] is probably not 

 important, as the insects hve chiefly on the buds. In laying out new 

 plantations all foci hkely to harbour Helopeltis should be done away 

 with. The control of this pest is difficult. Careful and clean culti- 

 vation is very important and the trees should never be allowed to grow 

 wild. Breeding foci and the borders of cacao plantations should be 

 planted with Hevea or coffee. Catch crops between the trees should 

 be avoided. Direct control measures consist largely in the choice of 

 varieties of tea and cinchona which are least liable to attack, e.g. the 

 fine Assam sorts in the case of tea. The existence of a resistant variety 

 of cacao is doubtful, though some types resist better than others, and 

 improvement in this direction might be produced by selection. In 

 addition to birds, the natural enemies of Helopeltis include Mantids, 

 Reduviids and spiders, but these, except perhaps the spiders, are not of 

 much importance. No parasites either of the eggs or larvae are as yet 

 known. Among insecticides, stomach poisons are of little use, there 

 are difficulties in the employment of petroleum soap emulsion and the 

 results are of no great value, but a thorough trial of CaUfornia mixture 

 as a repellent is desirable. Hand collection by children and burning 

 with paraffin torches are methods of some practical value [see this 

 Review, Ser. A, iii, p. 662]. Spider web and hoops covered with kapok 

 lint and mounted on long bamboos enable the insects to be swept off 

 the higher branches and caught. The torch method is the best on the 

 whole, but it is not necessary, as w^as generally supposed, that the 

 petroleum torch should emit a great quantity of smoke. In young 

 plantations, only hand-collection can be safely used and the torch 

 should only be applied, and that carefully, to those pods which are 

 attacked by Helopeltis at their ends. Very young fruits may be sprayed 

 with petroleum- soap emulsion with good effect, as this also prevents 

 fungus attack ; covering the pods with bags of paper or other material 

 is impracticable. For more than ten years the planters have been 

 persuaded that black ants [DolicJiodenis bituberculatus] keep down this 

 pest, and there is no doubt that plantations in which these ants have 

 been encouraged to the utmost suffer but little from Helopeltis. 

 Details are given as to methods of colonising these ants, including the 

 making of artificial nests and the distribution of these in the trees. 

 The gramang ant {Plagiolepis longipes) must be kept away, as it will 

 destroy the black species. 



Wolf (F. A.). Further Studies on Peanut Leafspot. — Jl. Agric. 

 Research, Washington, B.C., v, no. 19, 7th February 1916, 

 pp. 891-902, 4 tables. [Received 1st September 1916.] 



Leafspot disease of peanuts [Arachis hypogaea], due to Cercospm-a 

 personata, may be disseminated by insects. Positive tests were given 

 by four orders of insects, namely, Orthoptera (grasshoppers and 

 katydids), Lepidoptera (larvae of Chloicidea (Heliothis) obsoleta), 

 Coleoptera {Megilla rnaculata, Epicauta vittata, and Chauliognathus sp.), 

 and Rhynchota (leaf -hoppers). Grasshoppers were found to be capable 

 of carrying conidia on the surface of the body for very considerable 

 distances, and the passage of the conidia through the ahmentary tract 



