Hi, I get a disease in my tomato plants. At the start of the season I dug out all the soil from the glass house and replaced it with fresh soil. I prepared the soil for planting by applying Tui tomato fertiliser and neem granules. The plants grew well and started producing fruit. Then some of the plants started to wilt. The stems dried out about 300mm up from the ground and killed the plant. If you open the stem there are what looks like black seeds inside the stem. I have attached some photos. I even took a sample to the local garden centre but they couldn't give me any advice. Please help. photos attached.

Hi Garry, that is a common fungal disease called Sclerotinia. The black 'seeds' are fungal fruiting bodies called sclerotes, these sclerotes remain in the soil for several years.  If it is only a couple of plants you may be able to carefully remove the infected plants, ensuring you do not drop any of the soil residue from the roots or leave any plant material behind. Dispose of all infected plant material and burn or throw in the rubbish, the soil may need to be removed if it is badly infected. If this has happened before consider growing another crop in the glasshouse that isn't related to the tomato family as it can infect other plants such as capsicum, chilli and egg plant. Alternatively, grow your tomatoes in the glasshouse in pots and containers. Sclerotinia is prevalent at any time of the year during cool wet weather. Your local garden centre may be able to recommend a suitable control. The Tui Team.