Sorry for the back-to-back posts, but I thought those of you growing chrysanthemums would be interested in this post from MSU on recognizing Tomato Spotted Wilt Virus symptoms in your crop.
To confirm the presence of TSWV, samples can be sent to Lab Services at the University of Guelph.
TSWV is vectored by thrips. With temperatures between 25 and 28 C for the next 10 days, thrips reproduction will be rapid. Control of thrips (and elimination of infected plant material) is necessary to reduce virus spread.
Thrips biological control can be achieved in floriculture greenhouses using the predatory mite Amblyseius swirskii and/or A. cucumeris in combination with the parasitic nematode S. felitiae and foliar applications of BotaniGard. Registered chemicals for thrips in Ontario include:
- DDVP smoke
- Met 52