Plant Diseases & Pathogens – List of Problems & Solutions with Pictures
Have a problem with fungus, mold, mildew or blight? We’ve got the solution. Control plant pathogens and diseases the organic way for healthy and safe vegetables to eat for you and your family.
Powdery mildew is a common fungal disease that affects a wide range of plants. It is a white or grey powdery coating usually forming first on the leaves or foliage of plants and spreads rapidly. It can also attack and distort young stems and flower buds as it withers infected tissue.
If the small white/gray powdery patches of mildew are just starting to form, it is not too late to save the plant. If it has spread to the entire plant or entire sections of the plant are engulfed, either remove the affected portions or the whole plant and properly dispose of it by composting far away or burning it.
Mildew-susceptible plants like peas, squash, tomato, zucchini and cucumber can benefit from a couple different sprays that have an anti-septic effect. Apparently, just spraying water on the leaves helps as the PM fungus does not like to be wet. If that doesn’t work, try milk spray as the proteins when exposed to sun (apply during bright sun) seems to do the trick. Lastly, if neither of those work, your area might just be too shady for your plant or it might be worth trying a natural tea tree oil soap spray or neem oil spray (~10 drops per gallon sprayed every other day until the problem is gone).
It is smart to control this disease quickly due to its rapid growth and to prevent it from spreading to other plants. If left untreated, powdery mildew can and will kill most annuals and significantly weaken other plants.
Molds and Fungi (fungus)
“Damping off” is a result of fungi such as Phytophthora and Pythium. Seedlings like lettuce will suddenly collapse with the rot. Soggy conditions, over-crowding or not enough fresh-air exchange (FAE) is most likely the cause. Try letting the soil dry out on the surface or to 1-2″ in-between watering and even try spreading a 1/2″ thick layer of sand on the surface.
Chamomile tea is a fungicide. Prepare a cup of chamomile tea, steeping for 10+ minutes. Once cool, it can be sprayed on the affected leaves. Be sure to spray both the top and the bottom of the leaves.
Cinnamon powder sprinkled around plants and soil also controls fungus.
If you can make or buy good quality Compost tea, this is extremely beneficial. Compost tea balances the microbes and bacteria in the soil, thus fighting the disease organisms and providing active healthy organisms and fertilizer to strengthen the plants natural immunity and make them resistant to all problems and pests – not just disease!
Wilt / Wilting
Wilt affects many plants and the fungal spores remain in the soil for years. Use any of the organic fungicide ideas above. If out of control, practice good crop-rotation.
Clean pots: Between seasons with clay pots, give them a good clean if any sign of disease or pests was in the previous plants.
Fusarium wilt in potted herbs plants are an example. A soak in bleach works, but then you must re-soak in plain water to remove the bleach. One part vinegar to 5 parts water is a better soak solution, and give the pot a good scrub down also.