Pesticides: Weeds and fungi and bugs, oh my!

Greetings Grow Appalachia family! Holly the HQ VISTA here. Last week was kind of a long week. We were back at Greenhouse 17  finishing up their high tunnels. Working with some AWESOME alternative spring breakers from the University of Missouri only sweetened the deal there. When we complete this last tunnel, Greenhouse will have SIX tunnels total in production! On an unrelated note, the city of Berea woke up Thursday morning to no power! You can thank a blown transformer for that. Nevertheless HQ was raring to go (albeit 2 hours later than usual) and we did what we could despite the unplanned lack of modern technology. Fortunately at about 10:30 we were restored to full power!

I’m going to be taking a little time talking about pesticides.  Many people associate pests as being bugs.  A pest, though, is simply an organism that is either causing damage or is somewhere where it isn’t wanted; pests can be plants (weeds), insects, or mammals (hands up if you have a deer problem) When most people think about pesticides, they probably have a mental image to the degree of standing out in your garden, wearing something close to a hazmat suit and spraying plants like a crazy person.  Fortunately, most pesticides don’t require you go out and spray like a crazy person- unless that’s your preferred M.O. In addition to liquids, pesticides come in dust or powder form, granules, ready-to use (requires no mixing and sold in cans or spray pumps), as a bait, or as a wettable powder (mixed with water).

*A brief word for those that may not be familiar with our program: Grow Appalachia focuses solely on organic products; thus, those that are participants with us and for us can only purchase organic.  Furthermore, the recommendations I’ll be making here are also organic.  We often mention this in our newsletters but, seeing as we have now transitioned into a more informative approach to our blogs, we felt the need to make this known here as well.

Now let’s get into the three groups of common pesticides:

1. Herbicides– Herbicides are pesticides that kill plants. Not all herbicides are created equal, though; certain herbicides target different functions and areas of the plant. Some target the leaves, which causes the plant to dry up, while others target water and nutrient uptake.  Herbicides also target different growth stages of plants.  If you want to halt seedling growth, apply a pre-emergent herbicide to the soil before the seedling emerges through the soil surface.  Make sure that a pre-emergent herbicide is either worked into the soil or applied before a rain.  On the flip side of pre-emergent herbicides are post-emergent herbicides, which are applied to already-emerged and growing weeds.  These require spray coverage and destroy leaf and stem tissues on contact.  Lastly, there are different factors that determine the effectiveness of herbicides: leaf area of the plant, plant size/age, water levels, humidity, and temperature.  It’s also important to remember that over-application or incorrect application can end up doing more harm than good.

Product suggestion: After doing a bit of research, I came across Avenger Weed Killer, which uses a naturally-occurring citrus oil as its primary active ingredient (Think of that oil that’s left behind on your hands after peeling an orange).  It is OMRI-listed and available commercially as well.  We at HQ, however, cannot personally vouch for its effectiveness.

2. Fungicides– Fungicides are responsible for killing or inhibiting the growth of fungi.  There are two primary types of fungicides: contact fungicides, which work on the plant’s surface, and systematic fungicide, which are absorbed by the plant and carried upward via the plant’s xylem (water-conducting tissues).  You can use fungicides as a preventative measure in low rates and long intervals in between applications, or use them in high rates and short intervals in between applications if an outbreak has already occurred.  With the latter method, it cannot reverse any damage already done to tissue, but it can protect any tissue that has not yet been affected.

Product suggestion: Neem oil, in addition to its insecticidal properties, also works as a fungicidal agent, especially for powdery mildew.  There are many products containing neem oil, so it may be best for you to conduct your own research or contact your local extension agent, depending on your individual situation.

3. Insecticides– Insecticides kills insects.  Plain and simple.  With insecticides, you can find them classified as either broad-spectrum (kills a variety of insects, such as beetles, caterpillars, aphids) or selective (kills only one type of insect, like caterpillars only).  Selective insecticides can also protect beneficial insect species.  In addition to selective and broad-spectrum, they work by contact, in which they must be absorbed into the body of the target in order to kill it, or systemically, which are absorbed by the plant through the roots or leaves- those work best to target aphids and some borers.  With systemic insecticides, they can take several weeks to become fully absorbed, so it’s best to apply them before the pests are considered active.  Furthermore, systemic insecticides can remain in the plants for a long time, so they may affect beneficial insect species as well.  You can read more about systemic insecticides here.

Product suggestion: Many of our sites use spinosad as an insecticide.  Spinosad is not the name of the brand, but rather, the active ingredient.  You can find it from Seven Springs Farm, an organic distributor based out of Virginia, which is also a popular retailer within our partner sites.

Sources: Madison County Master Gardener/UK Cooperative Extension Kentucky Master Gardener Manual
OMRI– Organic Materials Review Institute: an online “database” of products suitable for certified organic production

The Label

I’ve posted a sample label from our Master Gardener manual, and have given a brief description of what each number entails, of which you can read below.  Your county extension agent is also a great resource for all things debunking!

Sample pesticide label.

1. Product or trade name
2. Type of pesticide (insecticide, fungicide, etc)
3. Ingredient statement: Includes both the generic or chemical name and concentration of each active ingredient in the product and percentage of inert ingredients.
4. The net contents give how much product is in the container in units of liquid or dry measurement
5. Name and address of manufacturer
6 and 7. EPA registration number, which is unique for each pesticide. It ID’s the manufacturer and product and indicates approval from the EPA for its listed uses.
8. “Keep Out of Reach of Children”, which must be found on all pesticides.
9. Signal word, ranging from “Danger” (most toxic), “Warning” (moderately toxic) to “Caution” (least toxic).
10. Statement of first-aid treatment that should be given in the event of accidental exposure
11. The note to physician lists treatment information and antidotes and provides an emergency phone number for additional information.
12. Precautionary statements identifying potential hazards and ways to minimize risks or avoid them.
13. List of hazards to humans and domestic animals, as well as statements indicating which routes (mouth, skin, lungs, etc) ought to be protected. Appropriate personal protective equipment (PPE) will be listed here.
14. Environmental hazards warning potential risks to birds, fish, bees, and other wildlife, as well as the environment, i.e. in areas where run-off may occur.
15. Physical or chemical hazards indicate any potential fire, explosion, or chemical risks the product may pose.
16. Directions for use, which must begin with the statement “It is a violation of Federal law to use this product in a manner inconsistent with its labeling.”  The instructions list what pests it controls and the plants, crops or sites intended for protection. It also lists when, where, how, and in what form the product should be applied, proper equipment to be used, dosages, mixing instructions (unless you’re using a ready-to-use product), compatibility with other products, minimum time in between applications and entry into the area unprotected, and possible plant injuries.
17. Storage and disposal instructions. Pay close attention to temperatures listed.

Source: Madison County Master Gardener/UK Cooperative Extension Kentucky Master Gardener Manual

A few final tips: 

–Remember that pesticides are not a definitive approach for complete elimination of your pest problem. It may be in  your best interest to try several different approaches of pest control, such as crop rotation (Of which many of you already practice!)

-You are probably not going to kill every single bug/weed/wandering critter that comes through your garden.  That’s ok. Instead of focusing on killing every hindrance that isn’t your beloved tomatoes, try to focus on reducing the pest outbreak to an acceptable number. (We’ll be covering integrated pest management, or IPM, in our next newsletter)

Bees are good.

-Please follow every instruction on the label.  I don’t think that needs repeating; we just want you to be safe.

-Be aware of your surroundings, especially if you live near a water source or an area with abundant wildlife and vegetation. Leaching and run-off are very real possibilities.

-Have a material handy that is absorbent and can clean up a liquid spill. Cat litter works best for this. Dispose of any materials used to clean up a spill.

Lastly, I’ve included a link from Mother Earth News that contains a bit of information about organic pesticides, including some you can make yourself.  We are not endorsing homemade products here at Grow App HQ, nor can we vouch for their overall effectiveness, but I thought it was an interesting read nonetheless.

Got any questions or concerns? Give us a shout!

(Feature image c/o University of Georgia Dept. of Entomology)