Growing forget-me-nots can be a walk in the park if you know what signs of danger to be on the lookout for. Even though these plants have few problems, there’s always a risk of fungal disease or insect pests, so read up on the most common issues of forget-me-nots you’ll see in the garden. Whether you’re having forget-me-not troubles or are simply preparing for the worst, this article will help you find the results you want.
A robust stand of forget-me-nots is a truly remarkable sight, but that picture perfect image doesn’t simply happen by accident. Awe-inspiring forget-me-nots are the product of a grower who is intimately familiar with the common problems with forget-me-nots, from fungal disease to pest insects.
Although forget-me-nots are generally pretty tough once established in the landscape, that doesn’t mean that they’ll never have a problem. Luckily, most pests and diseases of forget-me-nots are pretty simple to control. Keep an eye out in the garden for these common forget-me-not pests and diseases for the best success with forget-me-nots:
Aphids. The sooner you catch these small, soft-bodied sap-suckers, the easier they are to get rid of, so inspect your plants regularly. They look a bit like tiny potatoes and don’t move once they start feeding on the undersides of plant leaves. A regular spray of water or manually wiping them from plants can control aphids adequately. Watch for ants that might be farming these aphids, since they can reestablish a colony quickly. Strategically placed ant baits can help control the tiny farmers.
Potato flea beetles. These seed-like black beetles feed on the undersides of plant leaves, causing significant discoloration and death to foliage, but aren’t considered serious pests of forget-me-nots. You can avoid inviting flea beetle pests into your stands by covering young plants with row covers until they’re established.
Slugs and snails. Of all the garden pests out there, slugs and snails have a special kind of notoriety about them. They can seem unstoppable, but they’re actually quite easy to arrest if you plan well. Go out at night and check your forget-me-not stand to ensure that the damage is coming from either slugs or snails. With a positive identification made, you can start hand-picking them if the stand is small, being sure to dunk the pests in a bucket full of soapy water as you find them.
Longer-term control can be achieved by planting aluminum pie pans around your plants and filling them with cheap beer. Slugs and snails don’t need a microbrew; they’re happy to jump in and spend their last nights soaking in the cheap stuff. Make sure to clean traps in the morning and reset until you’ve gone several nights without any new slugs or snails in your trap.
Crown rot. If your plants are starting to wilt and die and you notice thin cobweb-like threads on their bases, you’re probably dealing with Sclerotium delphinii. This serious fungal pathogen will destroy any forget-me-not it comes into contact with, so dig and destroy all affected plants and those that are immediate neighbors if you hope to control the spread.
Clean your tools carefully to ensure you don’t spread any spores that lead to crown rot. Infested soil should be destroyed when possible, or covered in clear plastic until the following spring to ensure the spores are adequately halted.
Other fungal diseases. Powdery mildew, leaf spots, rust and downy mildew are also common, but simple, problems of forget-me-nots. For these pathogens, make sure the area has plenty of good air circulation, remove all dead plant matter and treat with a fungicide like mancozeb or thiophanate-methyl as soon as signs appear.
December 17, 2020 by Shiny Aura
There is a flower called forget-me-not flower. It has a Latin name, Myosotis. On tall, hairy stems, this flower grows.
Sometimes, this plant can also grow up to two-feet tall. In general, it has five charming, blue petals with the yellow center.
Does the forget-me-not flower have the same forget-me-not meaning as you may think it is?
Fungal infections are common problems in forget-me-nots. Powdery mildew, which is caused by the Oidium or Erysiphe fungi, creates a powdery-white coating on the leaves, stems and blossoms. The leaves may fall prematurely from the plant, and buds and leaves are often twisted or deformed. Puccinia causes rust infections in forget-me-nots. Reddish orange spores appear on the stems or leaves. The tissue around the infected area often turns yellow, and infected plants may be smaller than their healthy counterparts. Leaf spot, which is caused by Phoma or Cercospora fungi, creates spots of dead or dying tissue on leaves. The Connecticut Agricultural Experiment Station suggests preventing powdery mildew, leaf spot and rust infections with sulfur. Add 2 to 2 1/4 tablespoons for each 1 gallon of water. Spray plants every five to 10 days, as well as after it rains. Avoid using sulfur when temperatures are over 90 degrees Fahrenheit, since sulfur can damage ornamental plants. Smut, a result of infection by the Entyloma fungus, leaves masses of black or white spores on plants. Smut does not require a fungicide control infections by removing infected plant debris. Sclerotium delphinii, the fungus that causes crown rot, is characterized by a web-like fungal growth at the base of forget-me-not plants. Infected plants usually wither and die. Remove and destroy the infected plants and the soil around them.
Plant Health Problems See Perennials for a detailed discussion of problems that may occur and are common to most herbaceous ornamentals.
Diseases caused by Fungi:
Crown rot, Sclerotium delphinii.
Plants wilt and die. The characteristic cobweb-like mycelium may be found at the base of the plant containing seed-like sclerotia.
Removal and destruction of infected plants and removal of infested soil is advisable.
Downy mildew, Peronospora myosotidis.
Pale spots appear on the upper sides of the leaves, with a downy corresponding growth on the lower sides.
Among the compounds registered for use in Connecticut is mancozeb. Consult the label for dosage rates and safety precautions.
Leaf spots, Cercospora or Phoma spp.
Leaf spots are very common, typically sharply delimited necrotic areas on plant leaves caused by a wide variety of pathogenic species. Leaf spots usually are favored by wet conditions and may become important if a large number of lesions are present or if they start to coalesce.
Under those conditions, control may also be achieved with the use of fungicides applied as soon as symptoms are visible. Among the compounds registered for use in Connecticut are thiophanate-methyl and sulfur. Consult the label for dosage rates and safety precautions.
Powdery mildew, Erysiphe or Oidium spp.
These fungi are obligate plant parasites which grow vegetatively on the plant leaf surface, sending haustoria, structures which absorb food from the host, into epidermal cells. The white mildew seen on the leaf is a combination of vegetative mycelium and spores borne in chains on upright conidiophores. Wind-dispersed mildew spores can germinate without free water under high humidity conditions, and disease is often severe when conditions are humid but dry. Small black over-wintering structures called perithecia are often found in powdery mildew affected areas.
Control may also be achieved with the use of fungicides applied as soon as symptoms are visible. Among the compounds registered for use in Connecticut are potassium bicarbonate, ultra fine oil, sulfur, triadimefon, or thiophanate-methyl fungicides. Consult the label for dosage rates, safety precautions, and directions for use.
Rust, Puccinia spp.
The term rust refers to both the disease and pathogen causing the disease. Symptoms of rust infection include rust-colored spores or gelatinous horns in powdery pustules on leaves or stems. Surrounding tissue is discolored and yellowed, and plants are often stunted.
Control of heteroecious rusts may be aided by removal of the alternate host, but for most perennials, control may also be achieved with the use of fungicides applied as soon as symptoms are visible. Among the compounds registered for use in Connecticut are sulfur and mancozeb. Consult the label for dosage rates, safety precautions, and directions for use.
Smut, Entyloma spp.
Smuts are diseases caused by fungi. While most smut diseases attack the reproductive parts of plants such as flowers, replacing them with a sooty black mass of fungal spores, smut diseases of perennials often result in light spots on leaves and are called white smuts.
This disease is not typically serious, and usually can be controlled by removal of infected plant debris.
Diseases caused by Phytoplasmas:
Aster yellows, phytoplasma.
The pathogen is a prokaryotic organism without cell walls. It infects the phloem of susceptible plants and causes a general yellowing and dwarfing symptom. The phytoplasma is spread by a leafhopper vector.
Infected plants should be removed and destroyed. Early season control of the leafhopper vector and removal of weed hosts may help prevent re-infection.
Diseases caused by Physiological/Environmental Factors:
Hot weather and drought can wilt and kill forget-me-nots. Consideration of environmental factors as well as laboratory analysis will help determine causal agent. Rhizoctonia solani can also cause rotting of the roots with consequent wilting due to lack of water in the plant.
The green peach aphid, Myzus persicae, feeds on foliage of forget-me-not and can be controlled with applications of malathion, imidacloprid or insecticidal soap, which are among the compounds registered for use against this pest in Connecticut. Consult the labels for dosage rates and safety precautions. Natural enemies, such as lacewings, ladybugs, and syrphid flies, usually provide adequate control.
Potato flea beetle, Epitrix cucumeris.
This is a small, black, jumping flea beetle that feeds upon the leaves of potato, tomato, tobacco, and many other plants, eating out small round holes from the underside, but leaving the upper epidermis. The remaining tissue soon dies, however, and falls away, leaving holes through the leaves that turn yellow and later turn brown and die. This beetle is not much more than 1/16" long. It lives through the winter under rubbish and in other sheltered places. The overwintering beetles lay eggs in the soil in June. The larvae feed upon tubers and roots of the host plants. An abnormal growth sometimes takes place around each injury. The larvae transform and beetles emerge early in July.
These beetles feed as long as the plants are green and temperatures are favorable. These insects then hibernate until the following spring. If the flea beetles are controlled in the spring when they first begin feeding, fewer beetles will be present in the fall and the following spring. See Flea Beetle fact sheet.
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Forget-me-not, any of several dozen species of the plant genus Myosotis (family Boraginaceae), native to temperate Eurasia and North America and to mountains of the Old World tropics. Some are favoured as garden plants for their clusters of blue flowers. (For Chinese forget-me-not, see hound’s-tongue.)
The woods forget-me-not (M. sylvatica), like most other Myosotis, changes colour from pink to blue as the tubular, flaring, five-lobed flower matures. The water forget-me-not (M. scorpioides) is shorter and has weaker stems it grows in marshlands but is otherwise similar. Both are perennial and occur in white- and pink-flowered forms as well as blue.
This article was most recently revised and updated by John P. Rafferty, Editor.