Comparative Rates of Population Growth of Pyrilla perpusilla (Walker) and its Ectoparasitoid, Epiricania melanoleuca (Fletcher) under Laboratory Conditions

摘要

Observations on the survival, development and reproduction of Pyrilla perpusilla (Walker) and its ectoparasitoid, Epiricania melanoleuca (Fletcher) were recorded in the laboratory to determine the comparative rates of population growth in these species. The finite rate of increase (λ) was higher (8.984/♀ /month) in the parasitoid than that of the host (4.711/♀/month). Host specificity and inadequate availability of the proper host stage for the randomly searching parasitoid larvae were found to belimiting for the rapid multiplication of the latter under field conditions. In view of the above limitations of E. melanoleuca, a control strategy against pyrilla has been suggested.