Fusarium wilt, blossom drop and growing healthy tomatoes

DEAR JESSICA: Can you tell by the pictures what the problem is with my tomato plants? This happens year after year. The plants were beautiful, bushy and healthy in June and the beginning of July. But in August, many of the branches slowly started turning yellow and the plants are dying. I make sure when I water that I do not get the leaves wet.

— Greg MacArthur,

Wantagh

DEAR GREG: It appears your plants are affected by fusarium wilt, a fungal disease that typically takes hold after flowers open on tomato plants. The disease results in blocked pathways inside stems that prevent adequate water circulation throughout the plant.

There really isn’t a cure, but because the fungus survives in soil, it will reinfect plants year after year unless you starve it. The only way to do that is to practice crop rotation: Don’t plant tomatoes or any other plant in the Solanaceae family (eggplants, potatoes, peppers) for three years. Without a suitable host on which to thrive during that period, the pathogen will weaken and dissipate. You can resume planting tomatoes in that spot in the fourth year.

DEAR JESSICA: I have tomato plants as well as some eggplants in my garden this year, and I am having great difficulty getting fruit on the plants. They are in fresh soil with compost added, fertilized once and evenly watered with full sun. I have beautiful, healthy plants with plenty of flowers that turn yellow and brown, and fall off within a couple of weeks. I’m fearing the cause may be related to pollination due to the loss of bees.

— C.J. Boothe,

Islip

DEAR C.J.: It appears your plants have tomato blossom drop, a circumstance caused by some sort of stress. Your plants don’t appear infested, they aren’t spotted and the foliage looks healthy, so I’m going to rule out pests or disease.

Sometimes when too many tomatoes are produced, the excess will “abort,” because the plant cannot support them all. But since you say you’re having difficulty getting fruit, I will assume this is not the case.

It’s impossible for me to know for sure what could be stressing your tomatoes and eggplants, but the most common stressors that can lead to blossom drop are either too much or too little water, too much or too little fertilizer, or too much or too little heat. You say your plants are in “fresh soil,” but what does that mean? Did you buy a soil mix that contained fertilizer? Fertilizing on top of that could lead to problems. And too much nitrogen fertilizer will support lush, green growth at the expense of flowers and fruit.

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It’s also very possible that extremes in temperatures are stressing your plants. This may or may not be out of your control. Are the plants situated in a spot that receives unrelenting sunlight all day or planted up against a reflective surface, like an aluminum shed? Or do they get fewer than six hours of direct sunlight daily?

All you can do, really, is ensure even watering that results in a total of one to two inches per week, place plants where they will receive at least six hours of sunlight daily and apply fertilizer according to package directions.

It also is indeed possible that poor pollination is to blame. Bees pollinate tomatoes and eggplants by shaking plants as they hop from flower to flower. Wind also is an effective pollinator. So shake your plants a bit every day. If pollination is to blame, future blossoms should produce fruit. Good luck!