Phytoparasitica (1989) 17, 63-64

E. Tanne, Y. Ben-Dov and B. Raccah (1989)
Transmission of closterovirus-like particles by mealybugs (Pseudococcidae) in Israel
Phytoparasitica 17 (1), 63-64
9th meeting of the international council for the study of viruses and virus diseases of the grapevine
Abstract: Until very recently, closteroviruses were known to be transmitted by aphids (Aphididae: Homoptera). In the last few years Rosciglione et at. (1983), Rosciglione and Castellano (1986) and later Engelbrach and Kasdorf (1986) were able to show that mealybugs (Homoptera: Coccoidea: Pseudococcidea), and in particular Planococcus ficus (Signoret), are able to acquire GVA, a closterovirus-like particle from leafoll (LR)-infected grapevines, and transmit it to Nicotiana clevelandi plants. In view of this, an effort was made in Israel to ascertain transmission of LR from grapes using mealybugs known to occur in vineyards. Virus-free Pseudococcus longispinus (Targioni Tozzatti) were raised on potato tubers. Adult females were transferred for larviposition onto LR-infected grapevines (detached leaves and whole plants were used for acquisition). First and second instar larvae were allowed an acquisition access feeding of 5-10 days and then transferred in groups of five to ten larvae to virus-free indicator plants ('Mission', 'Cabernet Franc', LN 33, RSG), which were kept for symptom development in an insect-proof greenhouse. The first symptoms (reddening and rolling of the leaves) were observed about 4 months after exposure to mealybug inoculations. Virus presence was verified by both ELISA and SEM. ELISA tests were carried out using NY-1 antiserum (kindly provided by Dr. D. Gonsalves): 9 were found positive out of 11 tested. Virus-free indicators were included in the test and found negative except for one Cabernet Franc plant which gave a positive reaction. ISEM tests were carried out using both NY-1 and GVA (kindly provided by Dr. M. Conti). Decorated closterovirus-like particles were observed in 6 of 9 tested. Virus-free indicators were included in the tests, and now was found to have virus particles.
This preliminary study demonstrated for the first time transmission of a closterovirus-like particle (ca 1800 nm) by the mealybug P. longispinus to virus-free indicator plants. Similar tests using P. ficus are underway. Field studies are being carried out to ascertain natural spread of the virus and attempts are being made to correlate it with mealybugs presence.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Database assignments for author(s): Yair Ben-Dov, Benjamin Raccah

Research topic(s) for pests/diseases/weeds:
transmission/dispersal of plant diseases

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Pseudococcus longispinus	Grapevine (Vitis)	Israel