138 NEBRASKA STATE HORTICULTURAL SOCIETY 



but the parasites, of which there are a number of different kinds, in- 

 crease much more rapidly so that before the season Is over 90% or more 

 of the "flies" may be destroyed so that the following year there are but 

 few to produce a new generation. 



Although these and countless other injurious insects are held in 

 check in their native home by their individual parasites, for, as a rule, 

 each parasite has its particular host and will attack no other unless 

 it be a closely related form, we sometimes have an insect, which in its 

 own country was never considered dangerous, brought nto a new country, 

 leaving Its parasitic enemies behind. Supposing a single egg-cluster con- 

 taining 200 eggs of a moth be shipped into this country on nursery stock. 

 In the first year 100 of these would develop into females which would lay 

 200 eggs apiece. The second year there would be 20,000 moths or 10,000 

 females. The third year there would be 1,000,000 females. The fourth 

 year, 100,000,000, while in the fifth year there would be 20,000,000,000 

 caterpillars, or a serious plague. This is not entirely theory. The 

 Eastern states are now coping with this very circumstance. Last year, 

 according to the report of the U. S. Bureau of Entomology, over one mil- 

 lion dollars of private and public funds were expended in fighting the 

 Brown-tail and Gypsy Moth. Whole tracts of land have been rendered 

 almost uninhabitable by hordes of these insects. Although artificial 

 methods have been employed and proven of great value still they have 

 not been able to keep up with the increase of the insects. Leading En- 

 tomologists recognize that they must depend largely upon parasites, and 

 consequently parasitized caterpillars from the native European home of 

 the moths are being shipped in by the wagon loads in the hopes of getting 

 some of the parasites established. Every precaution is taken to prevent 

 secondary parasites form escaping and destroying the beneficial parasites. 

 It was due to the great care which our nurserymen constantly exercise 

 with the aid of Professor Bruner that the Brown-tail Moth is not started 

 in our State. This spring winter-webs containing live caterpillars were 

 fonnd on nursery stock shipped here from France, the home of the 

 Brown-tail. 



While the parasites may do much, and Entomologists may do much. 

 Entomologists, parasites. Agriculturists, and Horticulturists must all 

 combine forces as friends in order to successfully combat our insect 

 enemies. 



