Native Plants

Q. Who is Mr. Smarty Plants?
A: There are those who suspect Wildflower Center volunteers are the culpable and capable culprits. Yet, others think staff members play some, albeit small, role. You can torture us with your plant questions, but we will never reveal the Green Guru's secret identity.
Did you know you can access the Native Plant Information Network with your web-enabled smartphone?
Ask Mr. Smarty Plants
Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.

rate this answer

Sunday - July 28, 2013
From: Jacksonville, FL
Region: Southeast
Topic: Butterfly Gardens, Herbs/Forbs
Title: Effects or insecticide on Monarch butterflies
Answered by: Guy Thompson
QUESTION:
Thank you for fielding questions about plants!! Our nursery just informed us that their milkweed grower was using imidacloprid in their milkweed production. As a follow up to the question already in your database about imidacloprid on milkweed and its toxicity; Are NEW plants grown from 1) the stalks of denuded (by the poor caterpillars) plants and 2) grown from seeds from a imidacloprid treated plant - are those plants subject to the same half life time frame?ANSWER:
The excerpt shown below must be the one you found in out database.
"Imidacloprid is a chemical to avoid if at all possible. It is a synthetic analog of nicotine and is slow to degrade in the environment. According to the National Pesticide Telecommunications Network, it has a half-life in sandy loam soil of greater than one year. In bright light it degrades faster, with a half life of 39 days. But even the degradation products that form inside plants are highly toxic to insects, and their half-life is not reported.
Imidacloprid has been implicated in the mysterious colony collapse disorder of honeybees. For this reason, certain countries, e.g., France, has outlawed its usage for many purposes.
It seems safe to assume that milkweeds treated with imidacloprid may be quite toxic to monarch caterpillars for an extended period. Mr. Smarty Plants recommends the use of much less toxic sprays, such as Safer soap, which may be less effective on aphids but harmless to monarch caterpillars."
The half life of the chemical will be the same no matter where it resides. The main question is the quantity that the caterpllars eat. Imidacloprid is a systemic compound, meaning that it moves throughout the entire plant and not just the parts sprayed. There might be enough on the denuded stalks to injure the caterpillars when they eat new leaves that have drawn the insecticide from the old stalks. But the amount of imidacloprid that might have entered the seed would be diluted so much in new plants grown from it that there should be no danger. The caterpillars would not ingest a large enough amount of the chemical to damage them. So the conservative solution is to start new plants from seed.
More Herbs/Forbs Questions
Is Iva Angustifolia Salt Tolerant?
October 22, 2015 - I was wondering about the salt tolerance of narrow-leaf sumpweed (Iva angustifolia). It is the predominant species on a disturbed site in Haynesville, LA where brine contamination is in question. Un...
view the full question and answer
Forage plants for deer in Central Texas
December 06, 2014 - Looking for best forage plants and seed for deer forage, Canyon Lake-New Braunfels, Tx. Have searched listings, but areas are NE or other and not relevant to my location. Your time much appreciated.
...
view the full question and answer
Removal of thistles from Columbus TX
May 20, 2014 - I am sorry if you have an answer in FAQs but I could not find it.
We recently cleared property near Columbus Texas of many cedars (ash junipers). This spring we experienced a profusion of thistle -...
view the full question and answer
Low maintenance, low growing native plants
August 21, 2007 - Mr. Smarty Plants,
Could you recommend several low growing easy to maintain plants for planting next to our house. The area for the plants is next to the house(white stone) in between the house and t...
view the full question and answer
Combining yellow columbine and Malvaviscus arboreus
March 07, 2008 - Can yellow columbine coexist peacefully with Malvaviscus arboreus? I have a nice stand of the former and would like to plant the latter to take over when the columbine starts to look ratty in the hea...
view the full question and answer
Support the Wildflower Center by Donating Online or Becoming a Member today. |