(Contribution to the investigation of infection of the larvae of European pine sawfly (Neodiprion sertifer) in different instars regarding to their insect parasites)

1989

S. 57-66

7 Abb., 7 Tab., Sh, Zfsg. En

Unselbständiges Werk

200032233

Using specific nuclear polyhedrosis virus (Baculovirus) against younger larve of Neodiprion sertifer a high mortality even over 90 % is achived, depending of the intensity of the feeding of the larvae and doses of the virus consumed. But with infection the older larvae the total mortalities are less because a part of the larvae stop to feed and does not consume lethal doses of the virusand they spinned cocoons. In laboratory conditions when larvae of N. sertifer of the tourth and oder instars were fed within the virus concentration about 10 6 pol/ml 49,09 to 56,38 % of the mortality were obtained. The data presented in table 1 und 2 shows that the most survived larvae which spinned cocoons were among earlier in forest collected and with virus infected larvae. More than 71 % male were eclosed from these cocoons. Later infection when the larvae were oder percents of the dying were bigger and spinning cocoons relatively smaller and from these cocoons eclosed more female what shows that at the time of infection the male larvae finished with feeding and avoing infection. From a part of the spinned cocoons in the same year does not eclosed the imagoes. From such, closed, cocoons in the next spring eclosed the parasites Lamahus eques and Lophyroplectus luteator. The second parasite was were more frequent. The data also shows that percents of the eclosed insect parasites were bigger in the cases when the time of the colecting. N. sertifer larvae in forest were later. It was statement that the same number (500) dead larvae and spinned cocoons were most lighter in case of the most earlier collected larvae in forest. All the gained data shows that we were dealing with ghe larvae of different sexes depending of the time of their collecting in forest at Deliblato Sand.