1724 INSECTS ETC. INJURIOUS TO VARIOUS CROPS 



After the flowering season of the tree (end of February to beginning 

 of March) the adult insect leaves the almond to attack the ovaries of new 

 fruits. Almonds with two kernels invariably contain two larvae. 



The writer has never found an egg of Eurytoma though he has examin- 

 ed numerous fruits; towards the end of May the fully grown larvae have 

 already appeared. 



The white larva is blind, without legs, with the head but slightly 

 developed and a body which is round in the middle but pointed at either 

 end. When it is taken from the fruit and exposed to the sun it rolls up and 

 dies, which proves that it cannot bear the direct ra^^s of the sun. Inside 

 the body a green liquid is produced, both in the larvae feeding on the green 

 almonds and on the ripe white kernels. Apparently these larvae have 

 great powers of resistance against changes of climate for all those raised 

 in the laboratory developed quite normally. Onfy i per cent of the larvae 

 in the fruits were dead. This insect seems to have few natural enemies which 

 explains why it has been able to invade Palestine to such an extent. The 

 varieties most liable to attack are Victoria and Princess, both of them bear- 

 ing fruits with soft shells. * 



In the Arabian almonds with hard shells the writer has discovered 

 other pests, notably the larvae of one of the Diptera. Eurytoma seems to 

 prefer the old trees. 



When the harvest time arrives (middle of July to beginning of August) 

 the kernel has been completely eaten, but the larva remains in the almond 

 until the following spring (February or March); it resists the winter cold 

 quite well. 



Experiments have been conducted to determine what influence tem- 

 perature has upon the insect's development. If almonds contain! :g larvae 

 are kept in a dark place at a temperature of 170-180 C, the adults are hatch- 

 ed out at the end of May instead of in February or March. Generally 

 hatching takes place between 8 and 9 in the morning when it is very hot. 

 The insects secrete a liquid to dissolve the shell of the fruit, and this makes 

 a hole through which the adult insect emerges. The females make larger 

 holes than the males, which perhaps affords one means of distinguishing 

 between the sexes. 



When there are two kernels and each contains a larva, the insects come 

 out by two different holes. The writer has sometimes found that one kernel 

 contains an adult insect just about to hatch out, while the other contains 

 quite a 3^oung larva. Therefore it is evident that the two eggs were de- 

 posited by different insects. 



I^oss of juice from the almond does not hinder the insect's development. 



The pupal stage lasts on an average for 2 or 3 weeks; during this time 

 the white grub gradually turns black. 



The insect can only be kept in check by picking and burning all the 

 fruits which have turned black, but from which the adults have not yet 

 escaped. 



