INSECTS ETC. INJURIOUS TO VARIOUS CROPS 



1723 



124S- Animal Pests of Rice in Java. — See No. 1229 of this BuUctin. 



12^9- Helopeltfs 3kni its Relations to Cacao Trees. — koepke, w., m Medcdeeiingen 



van het Proefstation Midden- Java, No. 21. Batavia, 1916. 



During the 3^ears 1901 and 1902 a very severe drought in Central Java 

 was accompanied by the presence of Helopeltis on Cacao trees. During 

 the following years when there were heavy rains the pest was much less 

 severe, but it again became serious during the years 1913, 1914 and 1915 

 which were unusually dry. The harm done led the writer to resune his 

 researches on Helopeltis. 



There are two species, H. antonii and H. theivora, which attack cacao 

 plantations. They resemble one another closely both in life historv^ and 

 in the damage they do. 



The female lays her eggs in parts of the tree where there is abundant 

 moisture, i. e. in the rind of the fruits, the young shoots, or even in the parts 

 of the stems which are not woody. Soon, a black patch appears at the place 

 where the eggs are laid, caused by necrosis of the surrounding tissues. 

 After 6 da3^s the larvae hatch out and scatter over the branches in search 

 of food. Ten days later they are mature. 



The places at which the insect feeds soon turn black and normal growth 

 ceases. The writer gives a list of the trees attacked b}' Helopeltis, in which 

 both wild and cultivated trees figure. 



Helopeltis flourishes best in shady damp places ,and for choice attacks 

 trees v/hich are not exposed to the sun. An account is given of the conditions 

 which favour the insects' dispersal and also of the relations that exist be- 

 tween ants and Helopeltis. 



For more than 10 years the writer has observed that whenever the black 

 cacao ants [Dolichodenis bituberculatus) occur in great numbers Helopeltis 

 disappears. He therefore suggests that the pest should be dealt with by 

 encouraging the presence of these ants in the plantations by providing them 

 with smtable nests hung from the trees. Another effective wa}^ of checking 

 the spread of Helopeltis when the attack is not severe is by catching the 

 insects. 



Where the attack is widespread and the insects are numerous it is a 

 good plan to burn the fruits and the stalks. 



J250- Eurytoma sp., an Hymenopteran Pest on Almond Trees in Palestine. — 



Aharoni, J., in Dcr Tropenp/lanzer, Year 19, No. 6, pp. 317-322. Berlin, 1916. 



The lar^-a of Eurytoma sp. causes very extensive damage to almond 

 trees in Palestine, 50 per cent of fruits being destroyed every year. 



When an almond is attacked it turns first brown and then black and 

 is in consequence unsmtable for food. The lar\'a does not live at the ex- 

 pense of one of the enemies of the almond tree but by destroying. the fruits 

 themselves. However in 600 blackened almonds 3 larvae of one of the Mi- 

 crolepidoptera have been found and one of a Curculionid, but it is not like- 

 ly that the^' were hosts of the Eurytoma larvae. Nevertheless the writer 

 does not believe that the presence of Eurytoma alone causes the blacken- 

 ing of the almonds, for man}- fruits which are black outside contain a nor- 

 mal, healthy kernel. 



INSECTS 



INJTJRIOUS 



TO VARIOUS 



CROPS 



