It would take more than good seeds to reap good harvest. Vegetable production entails having knowledge of usual plant diseases and attendant cultural practices to prevent losses. Below are some of the diseases that we have to prevent to have better quality harvest.
Bacterial spot (Xanthomonas campestris pv. Vesicatoria)

The bacterium affects leaves, stem, and fruits. Leaf becomes necrotic–where cells of infected tissues die–and circular to irregular shaped spots with brown centers and chlorotic borders appear. Bacterial spots can be prevented by using clean seeds and practicing crop rotation.
Damping off Disease (Pythium spp.)

Damping off disease manifests itself when infected young seedlings show soft girdled, rotten stem near the soil line that causes it to topple down. This can be prevented by adopting sustainable management practices such as crop rotation with cereal crops, soil sterilization through solarization, improving soil drainage, and applying Thrichodermaplus.
Stem rot (Sclerotium rolfsii Sacc.)

Plants with stem rot exhibits yellowing or wilting of the foliage beginning on the lower leaves, and dark brown lesions appear at the base of the stem.During the advanced stage of the disease, a white thread-like myceal growth covers the stem lesion. To reduce disease incidence, deep plow to bury sclerotia, remove plant debris, and practice crop rotation. It is also highly recommended that weeds be eradicated and dense planting be avoided.
For more information, you may contact Ramon Magsaysay-Center for Agricultural Research and Extension Services of the Central Luzon State University through +63444560704 and +063444560609.