Generally greenhouse crops are protected from pests and diseases which otherwise will not happen with outside field crops. However, if soil is not autoclaved there is problem of soil borne diseases like damping off caused by Pythium, Phytophthora etc., This can be taken care of adding biological control agents like Trichoderma viride/harzianum , Pseudomonas fluorescens and also chemical fungicides like Metalaxyl /Metalaxyl +Mancozeb/ Carbendazim to the soil. Nutrition can be given by providing foliar application of 17:17:17 N,P,K along with micronutrients . Sometimes sucking pests such as Thrips, Mites and other sucking pests can make their entry which can be kept under check by Dimethoate/Imidachloprid etc

Hi

Thanks a million

I wanna know What the disease of bacterial and viruses are in greenhouse seedling (tomato, cucumber, ...)?

Specifically under controlled conditions, these pests or bacteria could be kept under check but if the bacteria and viruses are seed transmitted , they pose a problem. I am also growing diffeent cucurbitaceae plants in green house for research like watermelon, cucumber, bottlegourd, musk melon but havent faced till now any disease ie., 45 days after sowing. If at all i face some diseases i will let you know and share the experience. Good Luck