The emergence of bulb flowers, such as tulips and crocuses, is a welcome sign that spring is arriving. A bulb is a special type of seed that has the nutrients needed for a young plant to receive a good start. Flowers that grow from bulbs are usually among the hardiest species when grown in good soil, although they may develop a few problems.
Botrytis is a fungus that mostly occurs in damaged plant parts between roots. Bulbs and roots beneath the bulb's skin can both be infected. Common symptoms of this disease are bulbs that are soft and dark brown with black sclerotia on diseased plants. Sclerotia are hardened funga masses containing food reserves. Plant parts above soil of an infected plant are brittle and can break quickly. Some plants that are heavily infected are stunted or don't even emerge from the ground.
Augusta disease, caused by a tobacco virus, is transferred to roots by cells of the bulb by a fungus known as Olpidium brassicae. Infected plants don't normally show symptoms, and the disease can quickly appear during a frost. This disease mostly occurs in tulips planted when temperatures are above 50 degrees F, after they've been stored. Using fresh planting soil, and waiting until temperatures drop before planting bulbs in the fall generally helps to prevent this problem, according to online retailer Tulip World.
Red Lily Beetle
Red lily beetles, troublesome from early spring to late summer, are ravenous pests that can destroy a lily quickly. Although they can be found on other plants, they only feed on lilies. An adult red lily beetle is bright-red and has black legs and a black head. Larvae are dirty-orange with black heads and have more of a rounded shape than adults. Hand-picking beetles and then drowning them in soapy water is one way of controlling these pests. Another treatment is using neem oil, which is a natural pesticide from seeds and fruits of an evergreen tree known as Azadirachta. Neem oil should be reapplied regularly because rain or dew can wash it off leaves.
Aphids are white or yellow-green insects roughly 1/8 inch long that feed on stems, stored bulbs and on the undersides of leaves. These pests suck a plant's juices which cause leaves to curl and flowers to be deformed. They also secrete honeydew which attracts ants that spread diseases. One of the most common aphids attacking flower bulbs are green peach aphids. Dahlias, irises, lilies and gladiolas are a few of the most vulnerable host bulb flowers.
Wireworms are smooth yellowish-brown larvae that's segmented and about ¾ inch long. They come from eggs laid in soil by black or brown beetles called click beetles. These larvae live only in soil and burrow into bulbs. They hollow out stems, working their way up, which causes a plant to eventually fall over. Their main targets are gladiolas, dahlias and tuberous begonias.