Studies on a new nuclear polyhedrosis virus of Yponomeuta evonymellus L. (Lep., Yponomeutidae) and its effects on different Yponomeuta species. 2. Efficiency and response of the virus to environmental factors
1986
Feemers, M. (Muenchen Univ. (Germany, F.R.). Lehrstuhl fuer Angewandte Zoologie)
After the first part reported on the morphology and pathology of a nuclear polyhedrosis virus isolated from Y. evonymellus larvae, the present part deals with the efficiency of this NVP on larvae and pupae as well as with its responses to environmental factors. The NVP was pathogenic to larvae and pupae of the following species: Y. cognatellus, Y. evonymellus, Y. padellus and Y. rorellus; however species belonging to other families than Yponomeutidae were not susceptible. LD(50-) and LT(50-) values, incubation and decline period of the 3 first named species were investigated for L3 and L4. From these data it could be derived the Y.padellus was the most susceptible whereas Y. evonymellus was the less susceptible species. But in each case L3 was more susceptible than L4. Furthermore differencen in susceptibility were observed in relation to the geographical origin of larvae population. Low virus dosages caused a second virus replication cycle which resulted in a mortality line with two maxima and for some individuals the incubation period was doubled. At 31 degrees C the virus replication was most efficient, whereas at 35 desgrees C virus replication was suppressed. Good results in field experiments revealed the chance for using the NVP as a control agent against Yponomeuta larvae
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