Estimation of nuclear polyhedrosis virus produced in field populations of the European pine sawfly, Neodiprion sertifer (Geoff.) (Hymenoptera: Diprionidae)

Publisher Website
Google Scholar
Abstract
The quantity of virus measured as the number of polyhedral inclusion bodies (PIB) produced and liberated at death from 2 diseased N. sertifer (Geoff.) populations was studied over a 3-yr period in Britain [UK]. As high as 2.3 .times. 1015 PIB/ha were produced as a result of a natural epizootic in one of the populations. Subsequent years saw an appreciable reduction in the quantity of the virus produced, a direct result of the reduction in the number of sawfly larvae infesting each plot. Polyhedra persisting over winter in the host''s environment altered the nature of subsequent epizootics by causing virus infection to occur at an earlier stage of larval development than previously observed. This increased the percentage contribution of PIBs from the death of early instar larvae to the total amount of virus produced.