SYNTHESIS, DISTRIBUTION AND SOME MULTIPLICATION SITES OF WHEAT STRIATE MOSAIC VIRUS IN A LEAFHOPPER VECTOR

The relative concentration of wheat striate mosaic virus in a leafhopper vector, Endria inimica (Say), and in certain tissues was determined at various times after the insects had acquired the virus by feeding on infected plants. The extracts of whole leafhoppers or tissues were injected into virus-free leafhoppers, and the latter were tested singly for their inoculativity on wheat (Triticum durum Desf.) seedlings. Dilution end point of the virus in the extracts or percentage transmission by insects injected at a certain dilution were used as criteria to determine the relative virus concentration in various inocula. The virus concentration in the exposed leafhoppers increased rapidly between days 1 and 7, then remained at about the same level up to day 42. The results indicate that the virus concentration increased about 5000-fold between days 1 and 7. The virus was first recovered from the alimentary canal by day 2 after a 1-day acquisition access feed and from the salivary glands, hemolymph, and hemocytes by day 4. The virus concentration increased rapidly in the alimentary canal, reached a peak by about day 8, and then decreased slightly between days 8 and 32. In the hemolymph, hemocytes, and salivary glands, the virus attained a plateau level in 6-8 days. The virus was recovered also from the fat body, brain, and mycetomes, but not from Malpighian tubules, ovaries, or testes, of viruliferous leafhoppers. © 1969.