Ailing Bulbs: Dealing with Common Pests and Diseases

Ailing Bulbs: Dealing with Common Pests and Diseases
Rodents, such as mice and squirrels, can wreak havoc on bulbs, especially crocuses. It generally helps to plant bulbs in containers or add some chicken wire over your plantings to prevent these pests from digging them up. I have found that applying sprigs of cat hair from my shedding feline, throughout the garden helps a lot as the smell of one of their own predators generally deters them, keeping them at bay while my plants healthy. Birds can sometimes, though rarely, affect bulbs. Most often, these pests go after the smaller, newly planted bulbs such as crocus. As with rodents, chicken wire or netting can prevent this problem. While bulb predators, such as rodents, can be detected quite easily, others such as mites or thrips may be more difficult to detect. Therefore, becoming familiar with some of the most common insect pests can prove to be a bulb gardener’s best defense. Aphids are most likely to be a problem for potted plants. These tiny green insects can be easily recognized as they form clusters around emerging foliage. Favorite ‘victims’ include tulips, gladioli, lilies, and hyacinths. Generally, a light spraying of soapy water will remove them. Thrips are usually more prone to attacking bulbs during hot weather, leaving silver spots on flowers and leaves. Gladiolus plants are generally favored and can be doused with soapy spray as well.

Have you noticed any dark, slender insects with pincers roaming about the bulb garden? You just encountered earwigs. While they mainly feed at night, their damage is easily detected by the small indentions they leave behind on both flowers and foliage. These insects are especially fond of dahlias. It often helps to keep any dead leaves or other debris cleaned up when it comes to preventing earwig infestations. The bright red backs of the lily beetle are easy to spot, especially when you look for their favorites, like lilies and fritillaries. These bugs can cause major damage to plants if left untreated but can oftentimes be easily picked off by hand or washed off with soapy sprays. The larvae of narcissus flies, which resemble maggots, commonly affect narcissus and hyacinth bulbs. To prevent further destruction, it is generally best to remove the affected bulbs. Cutworms live beneath the soil and are green or grayish in color. These pests will devour the roots and bulbs of many plants. Remove and destroy any affected bulbs to prevent further problems. As eelworms are too tiny to see, their destruction is quite evident, causing softened bulbs and weakened growth. You may also see dark rings within cut bulbs. The most likely candidates for the attacks of eelworms are narcissi, snowdrops, irises, tulips, and hyacinths. All affected bulbs should be removed and the site should not be planted with anything for at least three years. Considered a huge nuisance in the garden, snails and slugs enjoy moist soil the best. Bulbs are most susceptible to snail damage as young shoots emerge from the ground, while slugs will attack from beneath the soil, hollowing out the bulbs. Dahlias, tulips, lilies, and gladioli are generally the most susceptible. Keeping the areas drier and free of debris can help. Believe it or not, garden-friendly wildlife can also deter these pests as well as many others.

Besides pest problems, bulbs can sometimes be affected by disease or other afflictions. Again, becoming familiar with the most common of these can prevent future problems. The best cure for any one of these afflictions is to dig up the affected bulbs and plants and discard them. Bulb rot is probably the most common. This is generally caused by over watering or unsuitable drainage. Typically, softened or rotten bulbs easily identify this problem. Other types of bulb rot can also occur, such as dry rot and hard rot, often affecting corms. With dry rot, black spots can be seen on the outer part of corms and eventually decay. Hard rot spots are brown and the affected corm will usually shrivel up. Botrytis, or grey mould, is usually identified by fuzzy grey mould on the leaves and flowers as well as the bulb itself. This usually occurs during humid conditions and often affects lilies, dahlias, tulips, and anemones. Tulip fire results in distorted leaves with scorched areas and stunted growth. Small fungal growths may appear on the outer scales of affected plants. Viruses usually include streaked flower color, mottled foliage, stunted growth, and distorted leaves. Generally, viruses do not cause any serious damage to the plant, and there is no cure. However, keeping an eye on and removing affected plants, like lilies and tulips, can help prevent the spreading of viruses.

Other disorders that may affect your bulbs can also occur. For instance, sudden cold snaps can damage developing leaves and shoots. The result from cold damage is loss of chlorophyll, leaving yellow-edged or white areas in affected leaves, which can be carefully picked off the plant. Very yellow leaves can be a symptom of poor drainage. Check to make sure that the plant in question is not situated in a wet site. If your flowers have failed to bloom, there may be several reasons. Pests could be a likely culprit so check for this first. Also, check the location of the plants. Are they getting enough light? After these considerations, you may need to dig them up and carefully inspect the bulbs for any problems. Otherwise, the plants may have become overcrowded and division may be necessary.

You don’t have to be an expert to detect problems with your bulbs. You only need to be watchful and familiar with the basics in order to protect your precious plants from falling victim to pests or diseases.

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