Wednesday, November 11, 2009

IPM - Part 2

Integrated Pest Management - IPM (Continued from last post)

"Unless someone like you cares a whole awful lot,
Nothing is going to get better. It's not."
— Dr. Seuss, from The Lorax

This is an extremely long post and for that, I apologize. Even with all its length, I could not cover everything. It is not a scholarly work – I am as far from being a chemist as anyone could be - but I’m determined to continue my journey through IPM with the Japanese beetle as best I can.

In order to make an informed decision, I need to understand the effects of the options from the last post - chemical, biological or mechanical. I started with a spray for adult beetle.

Spraying – Chemical Control of Adult Japanese Beetle

Have you ever read a pesticide label - that is, assuming you have excellent eyesight or a magnifying glass? Directions for use are very clear. “Read the label and follow the directions”, has become a gardening mantra. I can do that.

But what is in the spray? I chose Bayer Advanced Dual Action Rose and Flower Insect Killer because it is labeled for Japanese beetles (adult). I mean to neither promote nor condemn this product but I had to pick something. I have not used this product. This is simply an example of what it took for me to understand a pesticide label.

Bayer Advanced Dual Action Rose and Flower Insect Killer label:
ß-cyfluthrin................................. 0.0015%
Imidacloprid.............................. 0.012%
OTHER INGREDIENTS.................... 99.9865%
ß-cyfluthrin is the chemical name for Tempo® Ultra.
Imidacloprid is the chemical name for Merit®.
EPA Reg. No. 72155-28
EPA Est. No. indicated by 2nd and 3rd digits of the batch number on
this package. (65) = 432-TX-1 (39) = 58996-MO-1
(68) = 67572-GA-1 (75) = 5905-AR-1 3953398 R.0

I used Extoxnet and clicked on Pesticide Information Profiles (PIP) link to find the chemicals in this spray. It reads like a scholarly/governmental publication.

As far as I can tell from the label, this spray is in Toxicity Category III – “Caution” (Slightly Toxic). The Toxicity Categories are: IV None, III Caution; II Warning, I Danger - with “Category I Danger” being the most toxic. This scale is based on the LD50 number.

LD50 is the amount of pesticide, measured in milligrams per kilogram of body weight, that will kill one half of the exposed population.

First, ß-cyfluthrin – Tempo® Ultra

LD50 for a 150 lb. human for category III Caution ingestion total of one ounce to one pint, I think. I could use some help here. I found the Toxicity section of Extoxnet difficult to understand. From what I got it would take a pint of Cyfluthrin to kill 50% of the chickens or something like that. If you understand this measurement, please enlighten me. The amount of beta-cyfluthrin in this spray is .0015% in 24 fl. oz. or close to 1/25th of an ounce.

“Cyfluthrin is a synthetic pyrethroid insecticide that has both contact and stomach poison action” What is a pyrethroid? Pyrethroids are axonic poisons. Definition from Wikipedia: “Pyrethroids are axonic poisons that work by keeping the sodium channels open in the neuronal membranes of insects.” (Huh?)

There is a lot more information in the PIP but how much can you read before your brain goes tilt?

Next, Imidacloprid - Merit®.

Extension Toxicology Network search for Imidacloprid brought up a Pesticide Information Profile. “Imidacloprid is a systemic, chloro-nicotinyl insecticide with soil, seed and foliar uses for the control of sucking insects…”

I won’t go through the entire toxicity report. Imidacloprid is moderately toxic to mammals. LD50 is 450 mg/kg body weight in rats – the low end of category III Warning. The spray contains .012% or somewhere near 1/5th of an ounce.
Environmental Effect

I thought I would look at the Environmental Fate section of the PIP and try to understand the long term effects of Imidacloprid on the environment. “The half-life of imidacloprid in soil is 48-190 days, depending on the amount of ground cover.” “The half-life in water is much greater than 31 days at pH 5, 7 and 9. No other information was found.” I have no idea what the “Breakdown of Chemical in Vegetation” section means.

Effects on other animals

Are there animals that eat the beetles that will be affected by the poisons? I remember the disastrous effect of DDT sprays on birds. I couldn’t find any helpful information on this level.

Also, while eliminating one pest, I don’t want to kill beneficial insects and make my garden problems worse. A warning on the label:“• Apply the product to flowering plants during early morning or late evening, when bees are not present.” I must assume it will kill beneficial insects and another good reason to follow label directions.

What about groundwater contamination? Since it is sprayed on foliage groundwater contamination does not seem to be a major concern.

Agriicultural and Environmental News from Dr. Allan S. Felsot, Environmental Toxicologist, a Washington State University has this to say:

"Imidacloprid has a comparatively high water solubility (510 mg/L) and very low vapor pressure (1.9 x 10-9 mm Hg), so it is unlikely to evaporate from soil and plant surfaces and become an air contaminant. On the other hand, its biodegradation rate in soil has been characterized as moderately slow, with about 50% of the applied residue dissipating in a range of 48-190 days.”

Other Ingredients

Who knows what 99.9865 “other ingredients” are? The answer, it turns out, is no one except the manufacturer.

According to EPA “Regulating Pesticides”

“An inert ingredient means any substance (or group of structurally similar substances if designated by the Agency), other than an active ingredient, which is intentionally included in a pesticide product. Inert ingredients play a key role in the effectiveness of a pesticidal product. For example, inert ingredients may serve as a solvent, allowing the pesticide's active ingredient to penetrate a plant's outer surface. . .”

I hope you can see difficulty of trying to interpret the pesticide label. I hope my conclusions are correct. (I kind of gave up at the end of this post and resorted to quotes. Sorry.)

One conclusion – we need an easier way for the public to make informed decisions about pesticide use. At least there is somewhere to look for information.

It seems that “slightly toxic” is just that – but it is not without concerns.

Next post will look at grub control and mechanical methods. I hope you return.

(Comments, arguments, corrections welcome)

Bethlehem Garden Club Flower Show

“Home for the Holidays”

to benefit BGC Scholarship Fund.
Ideas galore for your holiday décor.
Sale of house plants, baked goods, holiday decorations, books.
BGC always does a beautiful job. Come and enjoy.
Location: Advent Moravian Church, 3730 Jacksonville Rd. Bethlehem.
Dates: Friday, November 13, 3-8, Saturday November 14, 10-3.


Gerry Okimi said...

LD50 are the "lethal dose' re amount of the product required to kill 50% of the population. Usually expressed in mg/kg body weight. So something very toxic has a small number. Strychnine has a low number = 16 mg/kg of body weight. Sodium Chloride (salt)has a LD50 of 3000 mg/kg. Caffeine has a LD50 of 192. Imidacloprid is about half as toxic as caffeine. LD50's give a relative scale to compare one product with another.
Most often you will see the LD50's expressed as for rats or mice. And rats and mice are useful in this type of testing. Sometime you will see numbers given for humans, but how did they come up with that number. Also LD50's are often stated as for oral vs dermal. Via the mouth vs through the skin.

Marie said...

Thank you so much for the explanation. That was very helpful.

How DO they come up with a number for humans? A scary thought.

donna said...

Marie, if you lived a little closer I be at the BGC Flower Show in a minute.

My mind is too full at the moment to properly absorb all the IPM info you've shared with us. You're way smarter than I am. Luv the Dr. Seuss quote.

Marie said...

I helped with flower show set up yesterday. It's going to be beautiful. They are raffling off two large jasmine plants. I'll let you know if I win one.

My mind is too full of IPM too. It turned out to be more labor intensive than I imagined.

Jane Johnson said...

The show was BEAUTIFUL! ...such a lot of work!
And I loved meeting you, Marie. xxx J

Marie said...

It was great fun! Thank you for the compliment. I am always amazed by the creativity and talent of the club members. We had a wonderful panel of judges! I was so happy to meet you and have a little chat. :-)