dark spots on tomato foliage make you wonder if something is wrong with your crop of tomatoes. Or maybe you think it’s all over: One little issue means no crop at all?
Tomato woes is rarely due to insufficient sun or moisture. Instead, an army of unseen pathogens are carried on raindrops, wind, and our own grooming tools between beds as we tend to our crops.
How to Stop Tomato Diseases
Knowing which diseases to watch out for… And how to deal with them; is less about chemical know-how different than plant selection skill. The codes on seed packets translate into survival odds for your plants. The resistance chart turn those numbers into language we humans understand.
On a seed bag, you may see things like V-F-N-TM, and figure, who knows? I don’t get it! But these codes aren’t gibberish. In fact, they’re a guarantee from breeder as to the plant’s ability to fend for itself with minimal help from us.
A high-resistance code (H) indicates that the plant actualy restricts the progression of the disease. That’s no label; that’s a biological firewall. And here’s why it makes a difference: It shifts you from frantic-reactive mode to casual-observation mode.
Soil-borne diseases: Fusarium and verticillium wilt can lurk in your soil for 10-plus years. They wait patiently to infect their next unsuspecting victim, which means you, if you grew a weak variety in infested ground.
Symptoms includes the sudden onset of yellowing (one side of plant at a time) followed by wilting (again, not responding to watering). You’ve invited the problem in when you sow a non-resistant variety in old ground. Look at the chart and see that those labeled “hybrid” like Celebrity or Mountain Fresh is well defended against such dangers.
Heirlooms, including Brandywine, tend to offer no protection whatsoever. Yes, go ahead and try growing them, but do so aware of what you may be inviting in.
Immunity is not resistance. Plants rated “intermediate” slows the disease down; they don’t block it completely, though they do reduce its severity. That’s where cultural practices comes into play.
Even with a resistant plant, you will still want to keep its foliage dry and prune out areas for better airflow… But at least the plant affords you some time to act.
Cool wet weather drive late blight, which can destroy a crop in a matter of weeks. No one variety prevents it completely, making early detection and preventive sprays critical even among resistant plants. Think of it as layering your defenses, not just using one solution.
For bacterial/viral pathogens, which also move around via contact (not just spores), another approach: These bugs don’t just jump ship from infected to healthy plant; their spores can hang out in clothing or tools for years until someone’s carelessness spreads them.
The best defense against contact-transmitted viruses? Wash up before working with plants. Sounds obvious, right, but that simple act of washing our hands is the single most effective sanitation tactic against these pathogens.
Once a virus gets into a plant, there is no treatment. Prevention is the only thing that will work. Preventing a virus means breaking its chain of transmission before it occurs.
Finally, mix good tactics like timing. Combine smart timing with resistant varieties. Starve out the soil-borne pathogen by rotating crops every couple of years. Use either sulfur or copper fungicide before humidity increases, not after you have white powder all over the foliage. In summer, solarize, cooking away fungal spores and nematodes with heat in the soil.
It is a system, not a one-time thing. Select a resistant variety then reinforce that tactic with common-sense culture, working with nature rather than against it. Move from guessing what went wrong to knowing why everything went right.
You should of selected better varietys.