35 



observed that on apricots and peaches they develop in a shorter time 

 than on apples at the same temperature, while the longest time was 

 required on pears. Probably this depends on the structure of the 

 tissues of the fruit, and it is therefore possible that in California only 

 two generations were obtainable, because the investigations there were 

 conducted on pears. 



The control of Cydia pomonella by means of natural enemies is 

 very popular in America and also has its advocates in Russia. 

 According to Portchinsky, there are 15 species of hymenopterous 

 and three species of Tachinid parasites which attack this pest. In 

 Europe more parasites occur than in America, where only six species 

 are known, and consequently the damage done there is far greater 

 than in Europe. As it was thought by Portchinsky that no local 

 parasites of C. pomojiella exist in Turkestan, several experiments were 

 undertaken by Vassiliev and Radetzky to import Pentarthron carpo- 

 capsae, Ashm. from Astrachan, but in 1912 Plotnikov discovered in 

 Ferghana a parasite of this pest similar to the Astrachan species, and in 

 1913 another local egg-parasite was discovered in Tashkent. Of the 

 •last species, which is of a bright yellow colour, several parthenogenetic 

 generations were obtained and no males have been observed. This 

 parasite attacks the eggs of all species of Tortricidae, especially those 

 of Pandemis chondrillana, the eggs of which are similar to those of 

 C. pomonella, but are laid in heaps and not singly, the parasite leaving 

 uninfested the majority of the eggs in the centre of the heap. Some 

 eggs of C. pomonella which were infested by this parasite on 7th 

 September produced another generation, while others did not give 

 rise to parasites, the latter probably remaining in the egg-stage over 

 the winter. Thus the importation of parasites from Astrachan proved 

 to be quite unnecessary and the whole question of the biological method 

 requires still further research and study. 



Besides the egg-parasites, other enemies of C. pomonella were 

 observed in 1913, the most important being an Ichneumon, Hemiteles 

 carpocapsae, Kok., a new species which will shortly be described by 

 Kokujev. This is an external parasite, the females attacking the 

 caterpillars of C. pomonella in the cocoons, 41 per cent, of the hibernating 

 individuals being infested. The process of oviposition by this parasite 

 is described at length ; the female first drives its ovipositor through 

 the cocoon into the body of the caterpillar and tries to prevent the 

 escape of its victim from the cocoon by striking it with its antennae 

 and jaws over the head ; after about an hour the caterpillar becomes 

 quite motionless and the parasite deposits on it from one to five eggs. 

 Frequently the caterpillars are able to escape from the cocoons after 

 the first attack by the parasite and in such cases the latter follows its 

 victim, makes fresh wounds with its ovipositor and drinks its blood. 

 A species of Ascogaster and some other parasites which have not yet 

 been identified or studied, have been observed. A mite, Pedicidoides 

 ventricosus, Newp., also attacks the caterpillars and pupae of 

 C. pomonella, destroying from 5 to 25 per cent, of them, and 

 a prominent part in their destruction is played by ants of the genera 

 Camponotus, Formica (especially Formica rufiharhis) Myrmecocystus 

 and others. As, however, the method of controlling this pest by 

 means of its parasites is still far from reaching serious practical value, 

 spraying according to the American method is a necessity. 

 (C115) c2 



