Tomatoville® Gardening Forums - View Single Post - Bacterial/fungal management for 1 acre farm

bower · April 24, 2019

You haven't mentioned how much of the 1 acre is in tomatoes.
I agree that some kind of shelter to keep (most!) rain off the leaves would make a huge difference. There are varieties that are disease resistant (to some things), and which you can find by trial and error, but if you want the freedom to grow any kind of heirloom you will be much better off to invest in some shelter. Does not have to be a greenhouse, even a top with no sides will help. How are you supporting the toms, and could that be adapted to provide some shelter? If you can't shelter, mulch to prevent splashback from the soil and increase your time investment in support and pruning to maximize air circulation. (I have read that bacterial spot can travel on wind and rain though, so without cover you are likely to have trouble if it is in your area).

Two summers ago I managed 50 plants in greenhouse for my friend's organic farm. One day a week (or half a day) for pruning and tying was enough to keep the majority of plants healthy to the end of season. The rule of sanitation pruning is of course take away anything diseased first of all, and secondly prune to keep the air circulation good. Most important IMO is that you must remove blossom ends when you do your pruning. The dead tomato blossoms contain substances that promote fungal growth, and when they fall on a leaf or stem or fruit stem, they begin the disease process. So shake them off, pick them off and dispose with your prunings in a compost pile away from the growing area. Note: not sure about bacterial spot which may survive composting - the fungal diseases require plant material to live so once the plants are rotted it is gone.
Another thing I have noticed growing organically, is that the plants need N when they start to ripen their fruit, and if you're not feeding them they will take it from the lower leaves. As they withdraw N they also withdraw immune support from those leaves, and whatever disease they are susceptible to, they will come down with. This can be forestalled by feeding them as ripe time approaches and keep feeding them weekly or biweekly as needed, fish fert or other.

In my experience, large beefsteaks are the hardest to keep disease free - maybe two reasons other than genetics (1) they really need that extra fert as they load up and start to ripen, because of the large fruit, and (2) the fruit shape that has a depression around the stem end gathers water/moisture and is perfect for mold growth. So you may have better results with hearts or other shapes that have no depression around the stem end.

April 24, 2019	#6
bower Tomatovillian™ Join Date: Feb 2012 Location: Newfoundland, Canada Posts: 6,794	You haven't mentioned how much of the 1 acre is in tomatoes. I agree that some kind of shelter to keep (most!) rain off the leaves would make a huge difference. There are varieties that are disease resistant (to some things), and which you can find by trial and error, but if you want the freedom to grow any kind of heirloom you will be much better off to invest in some shelter. Does not have to be a greenhouse, even a top with no sides will help. How are you supporting the toms, and could that be adapted to provide some shelter? If you can't shelter, mulch to prevent splashback from the soil and increase your time investment in support and pruning to maximize air circulation. (I have read that bacterial spot can travel on wind and rain though, so without cover you are likely to have trouble if it is in your area). Two summers ago I managed 50 plants in greenhouse for my friend's organic farm. One day a week (or half a day) for pruning and tying was enough to keep the majority of plants healthy to the end of season. The rule of sanitation pruning is of course take away anything diseased first of all, and secondly prune to keep the air circulation good. Most important IMO is that you must remove blossom ends when you do your pruning. The dead tomato blossoms contain substances that promote fungal growth, and when they fall on a leaf or stem or fruit stem, they begin the disease process. So shake them off, pick them off and dispose with your prunings in a compost pile away from the growing area. Note: not sure about bacterial spot which may survive composting - the fungal diseases require plant material to live so once the plants are rotted it is gone. Another thing I have noticed growing organically, is that the plants need N when they start to ripen their fruit, and if you're not feeding them they will take it from the lower leaves. As they withdraw N they also withdraw immune support from those leaves, and whatever disease they are susceptible to, they will come down with. This can be forestalled by feeding them as ripe time approaches and keep feeding them weekly or biweekly as needed, fish fert or other. In my experience, large beefsteaks are the hardest to keep disease free - maybe two reasons other than genetics (1) they really need that extra fert as they load up and start to ripen, because of the large fruit, and (2) the fruit shape that has a depression around the stem end gathers water/moisture and is perfect for mold growth. So you may have better results with hearts or other shapes that have no depression around the stem end.