The amaryllis produces 8- to 12-inch-diameter blooms on each leafless stalk. Stalks can grow 2 to 3 feet tall and bear as many as six blossoms. Cultivars (cultivated varieties) with single tiered or double flowers are available. Red and scarlet are the most popular colors. They are admired because they can produce flowers in mid-winter and add color to the indoors. However, despite their popularity, there can be bug problems with the amaryllis too.
The poly tea gloriosae is the most common caterpillar. It attacks plants from June to August and can eat all the leaves in four to five days. Simple attention to the plant is important for preventing caterpillar infestation. Hand watering encourages time with the plant to pay attention to insect activity. Hand picking upon sight and drowning in soapy water keeps the infestation under control. Some caterpillars are out at night, so handpicking should be done day and night. Other control methods include a spray of horticultural soap, especially for the amaryllis caterpillar. The spray smothers the caterpillar’s soft body and they die by suffocation.
Thrips feed on rapidly growing tissue. This causes tiny scars on leaves, called stippling, and can stunt growth. Damaged leaves may become papery and distorted. Infested leaves may become discolored, rolled, and then drop prematurely. Treating thrips is done weekly with an application of dust containing chlordane or dieldrin. The only prevention method is water. Dry plants are more likely to suffer from thrips, so watering frequently is important. If outdoors, use a mulch to keep in moisture .
Aphids and Mealybugs
Aphids and mealybugs are both soft-bodied bugs.
Aphids suck plant fluids, causing new growth to curl and become oddly shaped. The most serious result is the spread of virus diseases. Aphids need to be controlled at younger stages by spraying with a solution of 1 to 5 g of nicotine sulfate and 25 g of soap chips in one gallon of water or by 0.2 percent malathon every 10 days.
Mealybugs are covered with a white, waxy material. They attack plants by puncturing the leaves and sucking the juices. Mealybugs are controlled in the same method as aphids or with frequent spraying of water with a hose.
As with most of these bugs, simple attention to the plant is important for preventing infestation. Keep careful watch when watering and check often for signs of any bugs.
Spider mites are very tiny but cause big damage by feeding on the leaves of amaryllis during warm dry spells. They can be controlled or treated by spraying oramite at 0.2 lb./gallon of water.
Mites can be easily removed from a leaf surface before they dig in by a weekly hard blast of water. This can stop an infestation or slow it down once it starts. Spray the undersides of the leaves and the lower parts of the plant. Mites aren't found on the upper parts of the plant.
The best treatment for any bug infestation is prevention before a problem begins. Become familiar with the pests and diseases of plants and keep vigilant watch from the beginning. It is easier to prevent than to treat infestations. In addition, unnoticed bugs and pests can infect other plants causing damage to entire gardens or collections of houseplants.