ABSTRACT
Pepino mosaic virus (PepMV) is a seedborne virus of importance in greenhouse tomato. The ease of mechanical transmission of PepMV from contaminated tomato seed to seedlings makes commercial tomato seed a potential source of initial virus inoculum. The objective of this study was to evaluate the effectiveness of chemo- and thermotherapeutic treatments on PepMV using seed from a commercial hybrid tomato seed lot. The effect of various seed treatments was evaluated through bioassay with mechanical inoculation of the treated seed extract on indicator plants (Nicotiana benthamiana). Three commonly used seed-treatment chemicals and two thermo-treatment methods were evaluated. The most effective chemical was the commercial bleach solution (0.5 and 1.0% sodium hypochlorite), followed by trisodium phosphate. On the other hand, hydrochloric acid treatments were not effective. Under the stated chemotherapeutic treatment conditions, the rate of seed germination was not significantly affected. With thermotherapeutic treatments, although hot water soaking for 2 h at 55°C deactivated virus infectivity, it also resulted in a detrimental effect on seed germination. However, treatment with dry-heat baking (72 or 80°C for 48 to 72 h) was effective in reducing PepMV infection with minimum impact on seed germination.
