1919.] CONTROL OF THE CACAO THBIPS. b7 



TABLE ILLUSrEATING SEASONAL HISTORY OF THRIPS. 



Month. 



Season. 



May 

 June 

 July 



August 

 September. . 

 October .. 



November.. 

 December... 

 January . . 



Rainy 



February ... ,, 



Dr 



March 

 April 



Very dry 



Foo 1 Plants and parts of 

 them affected. 



Remarks. 



Wao, liavts oi lops of 

 trees. 



also Cacao pods and on 

 leaves of suckers. 



Heavy rains, thrips not 

 numerous. 



Thrips active and laj'- 

 ing eggs vhen laiiis 

 abate. 



Young stages and adults 

 numerous. 



Leaves of cacao dropping, 

 ■when severely attacked, 

 thiips living on pods 

 and suckers. 



also mango & almond leaver. 



Mangos, hog p 1 u m, IThrips decreasing on 

 cashew, guava and roses cacao 

 on leaves. 



Few thrips in any stage 

 on cacao. 



WHAT BECOME OF THRIPS IN THE DRY SEASON? 



Thrips do not disappear altogether during the dry season. The 

 numbers are greatly reduced owing to the want of moisture but they 

 always manage to e.xist in damp plao 's and on other plants than cacao. 

 The females are not very active iji laying eggs during the dry season and 

 most of the thrips pass through this season in the adult stage. It is not 

 possible for eggs to remain dormant in dry leaves on the ground, j 



HOW DO THRIPS DAMAGE CACAO? 



Thrips damage cacao principally by feeding on the sap of the leaves, 

 and when the attack is severe, drying them so much that they appear as if 

 scorched by fire and then drop from the tree. The pods are also 

 ■damaged, but in this case loss results chiefly owing to discoloration 

 of the skin making it difficult to know whether a pod is ripe or not. When 

 a great many leaves are damaged and have dropped from the trees, the 

 young and half -ripe pods will wither and in this manner the tree will- 

 lose its crop and have a sst back. See figure 5. 



