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themselves to thi-ips and generally appear after the worst damage has 

 been done. It is suggested that the introduction of some of these 

 from Trinidad should be tried. A predaceous thrips has been observed 

 in Grenada, but is not sufficiently numerous to be important. The 

 practice of encouraging black ants for the control of thrips is a great 

 mistake, as the numerous scale- insects and mealy-bugs, that they 

 foster on cacao are very injurious. 



Artificial control of thrips, which is a necessity for cacao growers, 

 should consist of spraying three times, at one month's interval, with 

 Bordeaux mixture 5:5: 50, to which is added nicotine sulphate 

 1 : 1000. The most impoi-tant spraying is the first, which should 

 be made just after the heavy rains. Kerosene emulsion is not 

 recommended and should be used only in an emergency. The most 

 suitable spraying machinery is described, and a table shows the 

 increased yield of cacao from sprayed as contrasted with unsprayed 

 trees. 



Cremastogaster hrevispinosa var. minutior (black, or acrobat ant) 

 should be controlled by cutting away and burning all dead twigs 

 and branches containing nests, and cutting out of the trunks of 

 trees all nests and dead wood and loose bark. Crude petroleum 

 should be applied to any cleaned-out part of a tree. -Vnother method 

 that has given success with the Argentine ant \Iridomyrmex humilis] 

 in Louisiana consists in feeding the ants with weak solutions of arsenic 

 which are strong enough to kill the larvae ; it is suggested that 

 experiments should be tried on these lines. Cacao trees are also 

 injured by certain beetles ; the usefulness of hzards in controUing 

 these pests and the need for their protection is emphasised. 



Coconuts in the Island are frequently injured by scale-insects, 

 particularly Aspidiotus destructor, but these are generally kept within 

 bounds by their natural enemies, provided that ants are kept from 

 the trees. If necessary, a spray of 1 part commercial lime-sulphur to 

 15 parts water should be applied. The soil where coconuts are grown 

 should be carefully drained, tilled and manured. 



The last section of this report, which is intended for the guidance 

 of the small proprietor and is issued as a separate paper, gives in a 

 popular form the information contained in the first part and includes 

 directions for spraying and instructions in preparing Bordeaux and 

 other popular mixtures. 



Smits van Burgst (C. A. L.). De oeconomische Beteekenis der 

 Sluipwespen. [The Economic Importance of Ichneumonids.] - 

 Tijdschr. Plantenziekten, Wageningen. xxiv, no. 3, Mav 1918, 

 pp. 116-122. [Received 3rd September 1918.] 



The Phytopathological Service at Wageningen is investigating 

 Ichneumonid parasites of Rhyacionia {Evetria) buoliana (European 

 pine-shoot moth), which causes severe injury to young pines in Holland, 

 and in the present article some notes are given concerning the value of 

 these parasites. In nature an Ichneumonid sometimes fails to attack 

 an insect under conditions where parasitism seems probable, and 

 furthermore, in a given region the various species parasitising a given 

 insect occur irregularly. In one year one species is the predominant 

 parasite and in another a different species plavs this role. In the 



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