Anti-GLRaV-3 coat protein polyclonal antibody

The effect of leaf removal treatments around vine cluster zones on must quality were tested during 2003 and 2004 in Rias Baixas (Spain) in two Albarino vineyards infected by GLRaV-3. As expected, the main virus damage was decreased sugar content (2.1 Brix in 2003 and 0.9 Brix in 2004) in the musts compared with leafroll-free plants. Leaf removal improved must quality by decreasing titratable acidity by between 0.5 and 1.9 g L-1 of tartaric acid, depending on the experiment; it also increased the grape sugar content an average of 1 Brix. In vineyards with high incidence of GLRaV-3, partial defoliation at veraison, or 2 to 3 weeks later, had an improved must quality, counteracting the negative impact of the virus. This process is recommended to avoid penalties in wineries during years with poor ripening conditions.

The vine mealybug, Planococcus ficus (Signoret, and the longtailed mealybug, Pseudococcus longispinus (Targioni Tozzetti), are vectors of grapevine leafroll-associated virus 3 (GRLaV-3), one of the most abundant viruses associated with grapevine leafroll disease. To elucidate the transmission biology in South Africa, acquisition access periods (AAPs), inoculation access periods (IAPs) and the retention of the virus in starving and feeding first- to second instar nymphs were determined. The rootstock hybrid LN33 served as virus source and grapevines (Vitis vinifera L., cv. Cabernet franc) served as recipient plants. An AAP of 15 min or an IAP of 15 min was sufficient for Pl. ficus to acquire or transmit GLRaV-3, respectively. Nymphs of PL firms retained the virus for at least eight days when feeding on a non-virus host and grapevine, and for at least two days when starving, and were then capable of transmitting it successfully to healthy grapevine plants. Nymphs of Ps. longispinus transmitted the virus after an AAP of 30 min and an IAP of 1 h. They retained the virus for at least three days when feeding on virus-free vines or starving. The GLRaV-3 infection rates of plants with PL fleas as vector varied with AAPs. These were lower (20 to 60%) for AAPs of 12 h or less than for AAPs of 24 h or more (80 to 100%). The findings are of importance for understanding the transmission biology of mealybug vectors and devising management strategies for grapevine leafroll