Asclepias fascicularis, also known as narrowleaf milkweed, is a common grown plant that gardeners covet for its unique appearance. Milkweeds are an abundant plant species found all over Europe, Africa, Australia and the Americas, including Hawaii. There are more than 3,000 individual species, and more than 90 percent are tropical. California milkweeds suffer from damage by a variety of pests, which gardeners must battle to keep their plants safe.
Narrowleaf milkweed is susceptible to a number of pests, including monarch butterfly caterpillars, aphids and colorful beetles. These pests tend to gather on the leaves and flowers of milkweeds, feeding off the stems, leaf tissue and seeds of the plant. Infestation can cause deformed leaves, damage to the seeds and a stunted development resulting from a lack of resources. It is also possible that invading pests can carry diseases or weaken the plant's resistance to infection.
There are a number of chemical insecticides available to help prevent, kill and remove infestations of insects. Some insecticides focus on killing eggs, larvae or other premature insects while others focus on adult invaders. These toxins can work either through skin absorption, ingestion, or repelling and starving the insect. Continued applications of insecticides will usually prevent reinfestation from pests.
Organic Insect Repellent
Organic insect repellents use naturally synthesized chemicals to remove and control pests. They often contain botanical pesticides or repellents such as Neem or Rotenone to keep pests away from plants such as milkweed. Studies, such as one performed at the University of Guelph and reported by Science Daily in June 2010, have shown that although organic repellents and pesticides are as effective as chemical-based sprays, they are not necessarily safer for the environment.
Research is important when identifying damage done to the milkweed. Gardeners may find the presence of beneficial insects and mistake them for dangerous threats to their plant. Some insects, such as caterpillars, are welcomed by gardeners for their eventual transformations, and options other insecticides are taken into consideration.
Many insecticides are not insect-specific, meaning that they will affect harmful and helpful insects when introduced to your plant. Gardeners also should be aware of the dangers insecticides can have on young children, pets and the environment. Limiting applications is one way gardeners can prevent accidents caused by insecticide poisoning or contaminating sensitive habitats.