The sweetpotato whitefly, Bemisia tabaci (Gennadius), is an economically important pest worldwide. A new biotype of sweetpotato whitefly, biotype B, causes extensive damage by direct feeding and by the transmission of plant viruses, such as geminiviruses. Because of the importance of whitefly-transmitted geminiviruses, studies were conducted to quantify the characteristics of tomato yellow leaf curl geminivirus (TYLCV) transmission by the vector B. tabaci. Transmission of an isolate of TYLCV from Egypt was achieved with one adult B. tabaci per plant, but the efficiency of transmission increased fourfold when the number of adults were increased to five per plant. B. tabaci transmitted TYLCV after a minimum acquisition-access period of 15 min, and rate of transmission increased as the acquisition-access period was lengthened and reached a maximum after 24 h. A minimum inoculation-access period of 15 min was observed with the rate of transmission increasing as the inoculation-access period was lengthened, reaching a maximum after a 12-h inoculation-access period. When B. tabaci were transferred serially after acquisition, adults were unable to transmit TILCV until 24 h after the initiation of the acquisition-access period regardless of the length of acquisition provided. The 24-h transmission threshold from initial vector access to a TYLCV-infected plant until transmission of the virus includes both the acquisition-access period and the latent period during which the virus circulates within the vector. Retention of TYLCV from the nymphal to adult stages of B. tabaci was supportive of a circulative mode of transmission. TILCV titer in B. tabaci after an acquisition-access period of 12 h continuously increased on a non-TYLCV host starting at 12 h, reaching a peak at 108 h and remaining stable from 132 to 180 h after the acquisition-access period. These data indicate multiplication of the virus in the vector as the most likely explanation for the continuous increase of TYLCV titer.
Document Type: Research Article
Publication date: October 1, 1994
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Journal of Economic Entomology is published bimonthly in February, April, June, August, October, and December. The journal publishes articles on the economic significance of insects and is divided into the following sections: apiculture & social insects; arthropods in relation to plant disease; forum; insecticide resistance and resistance management; ecotoxicology; biological and microbial control; ecology and behavior; sampling and biostatistics; household and structural insects; medical entomology; molecular entomology; veterinary entomology; forest entomology; horticultural entomology; field and forage crops, and small grains; stored-product; commodity treatment and quarantine entomology; and plant resistance. In addition to research papers, Journal of Economic Entomology publishes Letters to the Editor, interpretive articles in a Forum section, Short Communications, Rapid Communications, and Book Reviews.