Blight diseases are common fungal infections that can affect many ornamentals, including the popular balsam plant Symptoms like leaf spots, wilting, dieback, and stunted growth often indicate the presence of this disease When blight strikes, taking prompt action is key to saving balsam plants. With the right treatment strategies, balsam blight can be successfully controlled. This comprehensive guide covers blight identification, effective organic treatments, and prevention methods for balsam plants.
Recognizing Balsam Blight Infections
The first line of defense is identifying blight early before major damage occurs Look for these common symptoms
-
Small, water-soaked lesions on leaves that enlarge and turn brown. Lesions may have yellow halos.
-
Dark streaks on stems and petioles.
-
Leaves, flowers, and stems rapidly wilting and dying.
-
Defoliation and loss of flowers
-
Discolored, rotten roots.
-
Stunted, weakened overall growth.
-
White fungal growth visible on infected tissues in humid conditions.
Confirming the presence of blight early allows quicker treatment. Left untreated, blight can rapidly kill balsam plants.
Treating Balsam Blight Organically
Once blight is identified, organic treatment methods can help rescue affected balsam plants. Here are some effective options:
Remove Infected Plant Parts
Prune off any leaves, stems, or branches showing blight lesions. Also uproot and dispose of any severely infected plants. Discard this debris – do not compost. This helps reduce spread of fungal spores.
Use a Baking Soda Spray
The antifungal properties of baking soda can inhibit blight fungus. Mix 1 tablespoon baking soda + 1/2 teaspoon liquid soap + 1 quart water. Spray onto leaves, stems, and soil around plants every 1-2 weeks.
Apply Neem Oil
Neem oil coats plant surfaces with a protective barrier and contains antifungal compounds. Follow label directions and spray leaves, stems, and surrounding soil with neem oil every 7-10 days.
Improve Air Circulation
Thin dense growth, prune lower leaves, and space plants adequately to allow better airflow. This quick fix helps leaves dry out faster, deterring fungal growth.
Water at Soil Level
Avoid overhead watering methods that splash spores up onto foliage. Use drip irrigation or water at the base. Water early in the day so leaves fully dry out by night.
Boost Plant Health
Healthy, vigorous balsam plants better resist infections. Apply a balanced fertilizer and ensure plants get sufficient sunlight and moisture. Stress and weakness invite blight problems.
Rotate Balsam Plants
Avoid planting balsams in the same spot each year. Rotate them to different garden beds to prevent buildup of blight fungi in the soil.
Caught early, balsam blight can be successfully cured with these organic remedies. Be vigilant about monitoring plants and taking prompt action at first signs of disease.
Preventing Balsam Blight Long-Term
While dealing with current infections is important, prevention is the best defense against balsam blight long-term. Here are some key tips:
-
Select blight-resistant balsam varieties when available. Ask nurseries for recommendations.
-
Disinfect tools between plants with a 10% bleach solution.
-
Remove weeds – they can harbor blight pathogens.
-
Apply mulch to prevent soil splashing onto lower leaves.
-
Avoid overhead watering.
-
Water early in the day so plants dry out by nighttime.
-
Provide good spacing and air circulation.
-
Scout plants frequently and remove diseased parts immediately.
-
Follow crop rotation practices.
-
Apply preventive sprays of neem oil or copper fungicide early in the season.
-
Destroy severely infected plants and debris – do not compost.
With vigilance and prompt treatment, blight does not have to spell doom for balsam plants. Pay attention to cultural practices that discourage fungal pathogens. Follow these tips and balsam plants can thrive blight-free for seasons to come. A combination of monitoring, removal, spraying, and prevention techniques allows gardeners to successfully conquer balsam blight organically.
Don’t let downy mildew on impatiens surprise you
Use downy mildew fungicides preventively.
Figure 1. A, A yellow leaf, which can indicate downy mildew infection, compared to a healthy green leaf. B, Downy mildew fuzz on the underside of a leaf. C, Impatiens stunted by downy mildew infection.
Impatiens are one of the most popular bedding plants for shade gardens worldwide. In 2011, impatiens downy mildew was an unpleasant surprise for greenhouse growers and gardeners. Sometimes pathogens can seem cyclic and reoccur following several years of being absent.
Seed and vegetatively propagated Impatiens spp. including common seed impatiens (Impatiens walleriana), double impatiens and garden balsam (Impatiens balsamina) are susceptible. Fortunately, New Guinea impatiens (Impatiens hawkeri) appear to be tolerant or resistant to downy mildew. The downy mildew disease that affects Impatiens spp. is caused by a fungal-like microscopic organism called Plasmopara obducens. This downy mildew is unique to impatiens. Snapdragons, roses, impatiens, coleus, basil and other crops are susceptible to downy mildew, but each have a unique downy mildew pathogen. While the disease may look similar on the different crops, they are quite different. The downy mildew on snapdragons cannot blight roses nor can the downy mildew on impatiens spread to any plant outside of Impatiens.
In some cases before the pathogen is halted, the loss of plant material can be severe. Given these recent problems, growers should review the downy mildew basics because this can be an explosive, destructive and costly pest if it is not managed.
Downy mildew is not the same as powdery mildew. Powdery mildew commonly occurs on such plants as roses, gerbera, poinsettias, lilac and begonia.
Don’t forget to look under the leaves. An obvious sign of downy mildew is a white fuzz on the underside of the leaves, but this can go unnoticed (Fig 1B). Perhaps other than an especially severe case of Botrytis, no other disease causes such obvious fuzz, especially on the underside of the leaf. This disease should not be confused with spray residue, which can occasionally result in a whitish film on the leaves. Infected plants become stunted and lose their leaves, flower buds and flowers.
Look for the disease. Downy mildew is often explosive and early detection is critical. The downy mildew pathogen produces plenty of spores called sporangia that are spread via air currents to nearby healthy plants. When scouting, turn the leaves over to look for white fuzz (Fig. 1B). When receiving plug and liners of susceptible Impatiens spp., scout them immediately by examining fully-expanded leaves, paying special attention to the undersides of leaves. Scout a minimum of one out of every 30 plants. If there are symptoms of downy mildew infection such as distorted leaves or yellow foliage, but no white fuzz, they still may be infected with the downy mildew pathogen, but the conditions are not suitable for the pathogen to sporulate. Place the suspect plant in a plastic bag with a wet paper towel and leave it overnight. If the plant is infected, you should see white fuzz on the underside of the leaves the next morning.
Established impatiens crops should be scouted weekly. Be sure to check the impatiens that are in baskets and mixed containers as they can be hard to monitor. If diseased plants are discovered, they should be placed in bags and discarded immediately. Diseased plants should not be placed in a cull or compost pile. Healthy-appearing plants that are right next to the diseased plants should also be discarded as they are likely to be infected but are not yet showing symptoms. All remaining impatiens anywhere on the premises should be immediately treated with fungicides.
Downy mildew likes water and cool temperatures. Limit this disease by venting, reducing the time that leaves are wet, and keeping relative humidity to a minimum. Water plants at a time of day that allows the foliage to dry quickly. Downy mildew is a water mold because it needs water to grow and develop. Any strategy that reduces water, leaf wetness and relative humidity in a greenhouse will help limit downy mildew.
Apply effective fungicides preventively. Systemic fungicides can be especially helpful in managing downy mildew because these products are absorbed by the plant in a limited way and can fight the downy mildew pathogen effectively. Subdue MAXX and Segovis are both systemic fungicides and are especially effective when applied as a drench.
Two fungicide programs are outlined below. One is for the bedding impatiens and double impatiens that have not been bred to be resistant to downy mildew. The second is for those impatiens cultivars (e.g., Imara XDR impatiens and Beacon impatiens) that have been developed to resist infection by the downy mildew pathogen.
Preventive spray program for susceptible impatiens cultivars:
- First Application (Day 1)Subdue MAXX (1 fl oz/100 gal) drench. Treat soon after plants received unless propagator has treated just before shipment.
- Second application (Day 7)Segovis (3.2 fl oz/100 gal) drench. (Do not apply more than 9.6 fl oz of Segovis to a single crop annually.)
- Third application (Day 21)Segway (2.1-3.5 fl oz/100 gal; spray) or Orvego (11-14 fl oz/100 gal; spray) or Stature SC (6.12 fl oz/100 gal; spray) or Micora (4-8 fl oz/100 gal; spray)
- Final application, shortly before shipmentSubdue MAXX (1 fl oz/100 gal) + Segovis (3.2 fl oz/100 gal) drench. (Do not apply more than 9.6 fl oz of Segovis to a single crop annually.)
How to Kill Blight in Garden Soil
FAQ
How do you get rid of blight on plants?
How to get rid of tree blight?
Can you cure leaf blight?
What kills blight in soil naturally?