Understanding Pesticides

Transcription

1 Understanding Pesticides Slide 1 Hello everyone, my name is Mike Bush. I'm an Extension agent with WSU. Slide 2 Before we start talking about pesticides we're going to have to start identifying what exactly a pest is. My definition of what a pest is any organism that competes with humans for food. As we look at this picture, obviously the worm in the apple is outcompeting me for this apple. I'm not going to eat it, it's all theirs. This is what's inside this apple. Now it can be more than just insects, of course; we can have other organisms competing with us for food as well. For example, we have in this picture an apple that is showing obvious damage caused by birds, and a starling is usually one of the more common pests of apples in our area. Slide 3 A pest can also be an organism that competes with us not only for food, but indirectly or directly for water. And in this view we see a weed called scotch thistle. Now I'm about six feet tall and this thistle plant is taller than I am. It's a rather colorful weed with its purple flowers, but nevertheless it is a pest because it is competing with our orchards and our plants for water. Sometimes pests can come in forms that we don't recognize as pests. For example, this is a plant that had been in my garden for a few years before I finally identified what it was. And it turned out that it is a plant called loosestrife, a weed in fact, and it is considered a weed because of its nature of outcompeting the native plants in our wetlands and bogs and other moist habitats. Slide 4 Pests can also compete with us for food, water, and/or shelter. And obviously these roaches have the upper hand in this indoor basement. Sometimes it's difficult to distinguish between a pest and a beneficial. Outside, spiders are some of the most beneficial arthropods that we have in that they prey on other insects and arthropods, but indoors they're not such a good thing and they can be considered a pest. This is a picture of a hobo spider, please note that the scale here is in centimeters, so it is rather large for a house spider, but it isn't three (inches) long. Slide 5 A pest can also be an organism that may merely annoy man or beast. And here we have a picture of a bedbug feasting on my finger, and bedbugs may annoy both man and beast. And these pests, organisms that are consider a pest, may also be in the

2 form of insects or arthropods or other organisms that might vector disease as well; such as a mosquito, or organisms that cause disease in plants as well. And this is symptoms of a bacterium that causes fireblight in both pears and apples. Slide 6 Sometimes it's very difficult to distinguish between a pest in an organism or a beneficial. And to highlight this point I've taken a photo and I typically ask the audience to identify what the pest is in this picture. Now before you answer or think about this, I've got to let you know that this was taken when I was hiking around the Mount Blanc area, and at the time I was a single guy and I found out that there were a lot of single women that go on these tours. So with that information, I'd like you to look at this picture and tell me what the pest is. Now I've highlighted this as the pest because as it turns out I went on this hike with my younger sister and she did a really good job of acting as a chaperone, getting between me and the single women on this trip; so relatively speaking, I was considering this as a pest. Now if someone from one of the local weed boards had taken a look at this, they would have identified this as being the pest and they would have been quite anxious to find out where this pest was and go out and eradicate it because giant hogweed is considered to be a noxious pest here in the US. Over in Europe where it's originally from, it's not considered to be a weed. This is giant hogweed and again, I'm about six foot tall so this is an ornamental that in a garden that can certainly dominate the scene. But it is considered a weed and so another one of the definitions I often give is a pest can be an organism in the wrong place at the wrong time. Slide 7 So we've identified what a pest is, now what is a pesticide? A Latin suffix for a pesticide, "icide" is Latin for "to kill or destroy", and so that's what a pesticide does. It is designed to kill or destroy a pest. And often our pesticides contain chemicals that may be harmful not only to the target pest, but to people, children, pets, or the environment. Interesting to note that among all the pesticides that we talk about, even disinfectants are considered to be a pesticide, because, as the label says, bleach or Lysol here in this case is designed to kill germs. Whatever form of pesticide we use, it's important to use care when using the product because, after all, a pesticide is meant to kill or destroy some organism. Slide 8 Pesticides can come in a lot of different forms. Pesticides may be herbicides or algicides, and these types of pesticides are actually designed to kill green plants. In this case we are considering the plants to be weeds, perhaps algae or mosses, or in this picture, dandelions that are growing in the wrong place at the wrong time. This is also a picture of a plant known as goat's head, and certainly a target for a lot of herbicides we might apply to the system.

3 Slide 9 Now one thing to take note is that herbicides kill green plants. And so sometimes when we apply herbicides, we miss the target. And so it's very important to keep those pesticides on target. This is a view of a rose plant that was inadvertently sprayed with a chemical that is known as Roundup, a very common herbicide that homeowners use. And you can see that on the right, that's a normal rose growth and to the left is the abnormal plant growth caused by the herbicide missing the target. And certainly the other things that herbicide might affect is green tissues on trees on the landscape as well. This is just the scene of a cherry tree that has been affected by the herbicide Roundup as well. So again, with any sort of pesticide that is designed to kill an organism we need to use care when we apply it and to keep that herbicide on target. Slide 10 Another type of pesticide that we might encounter are bactericides and fungicides, also known as antibiotics, which are designed to kill disease pathogens. In this picture we see a little bit of ooze that is a sign of the bacteria that causes fireblight on apples. So a bactericide is a type of pesticide that is applied to control fireblight. Another type of pesticide might be a fungicide that's designed to kill powdery mildew on apples such as this. Again, there are other types of pesticides, antibiotics which are designed to kill microbes such as this, and way back earlier in this talk we talked about bleach and disinfectants whose target organisms are germs. Slide 11 Another type of pesticide that we might encounter are rodenticides and these are often in the form of baits that are designed to kill mice and rats. Again, like all pesticides, rodenticides must be used with care because they can affect non-target organisms such as domestic animals around the house. Slide 12 Another type of pesticide that homeowners might encounter are molluscides or piscicides. A molluscide is a pesticide that targets snails and slugs. And this is a picture of damage caused by a certain type of snail in the citrus groves of California. And here is a common leopard slug that may be affected by a molluscide. And piscicides are actually pesticides that are designed to kill pestiferous fish species. Slide 13 Other types of pesticides we might encounter are miticides, also known at acaricides, and they will target small little spider mites that might cause some damage on houseplants or plants out in the yard. These are microscopic little organisms. We might encounter nematicides which are products that are designed to kill nematodes or small

4 little worms that might be in the soil affecting the root systems of some of our desirable plant species. Slide 14 Of course, most of us are familiar with the insecticides or pesticides that are designed to kill insects, whether it be moths or wasps or other types of insects. These insecticides may come in various forms such as aerosols, which are designed to be sprayed on pestiferous insects. They may also come in the form of flea collars, lice shampoos, or in baits. And like all pesticides, again we want to make the point that we need to use these pesticides with care to make sure they do not drift and affect non target organisms, such as perhaps our most beneficial insect, the honeybee. One point to make on this is that we never want to spray flowers in bloom with an insecticide because that insecticide may affect our target organism, but it may also affect the honey bee, which is an insect, and again, one of our important beneficial insects. Slide 15 Insecticides may also take the form of repellents, which are chemicals that can change the behavior of a pest. Mosquito repellents, fly repellents, are a real common type of repellent that homeowners frequently use. Here in the upper right is a picture of pears that have been sprayed with a product called kaolin clay, and kaolin is marketed as Surround at Home and is actually a clay product that is sprayed on the surface of apples and fruit trees and pears in this case. And we're not exactly sure how kaolin clay works. Either it helps disguise the plant so the insects don't find it, or it serves as a minor irritant to the insects so that they go somewhere else. One of the interesting notes to make about the kaolin clay products that homeowners can use is that they work best if you use them and your neighbor doesn't. Because the kaolin clay doesn't kill anything, it just changes the behavior of the insect so they go somewhere else. The insecticides may come in the form of an attractant and often we have a number of bait formulations that use the concept of a pheromone in a goo that attracts the insects and this goo may also contain an insecticide, a small trace amount of insecticide that will kill those insects it attracts. So we have both attractants and repellants which are, strictly speaking, types of insecticides. Another type of attractant that homeowners might encounter is the pheromone ties that are used by commercial orchardist for the concept of mating disruption. So what happens is the grower will go out there and he will put all these different sorts of dispensers that release pheromones that are sort of like the perfume that the female codling moth uses to call in the male codling moth. So what commercial orchardists are doing now is they are putting out hundreds and thousands of these little bread ties or dispensers for pheromones and that prevents the male moth from finding a female, or if he does happen to find the female it takes so long that he's really reproductively spent. This is the concept of mating disruption that works very well in commercial orchards and might work to some degree in a backyard fruit tree.

5 Slide 16 Pesticides can work in a number of different ways. Most of the pesticides that homeowners utilize work by contact, which means that the pesticide must in some way touch the pest before it is effective. Often these pesticides are absorbed through the cuticle of the insect or through the skin of the pest. These are considered to be contact pesticides. Other pesticides may work as stomach poisons, which means in this case the insect pest must first ingest them before they are effective. Some pesticides work as fumigants, which means the target organism must inhale the fumigant to get a toxic dose of that pesticide. More and more, the products that homeowners have to use as pesticides against various pests work in a selective means. They are selective in that they kill just a narrow range of pests. For example, a pesticide may be selective specific to beetles and quite safe for moths and other organisms, other insect species out there. Another type of pesticide that homeowners might encounter are the systemic pesticides, and those are pesticides that are taken up by a plant or an animal and circulated through the organism. In this way a product might be rather selective towards its target organism. In this case a systemic insecticide is placed on the soil, washed into the soil, picked up by the roots of the plant and then carried through out to the tissues of the plant and in this way is selective in that only those insects that feed on the tissues of the plant get a toxic dose of the insecticide. Slide 17 Most of the pesticides that homeowners have access to are very highly regulated. In other words, there are a number of federal and state agencies that oversee the proper use and legal use of these pesticide products. Now, one example of a government entity with oversight on how pesticides are used and regulated is the US Environmental Protection Agency, which will actually determine the human safety of each pesticide product it registers as well as the efficacy of the product and the environmental risks that are associated with the use of that product. Another agency that has oversight on how pesticides are regulated is the Federal Food and Drug Administration, which actually monitors the pesticide residues that are on our national food strain. Another agency on the state level that has some say in how these pesticides are regulated is the Washington State Department of Agriculture, which oversees the pesticide applicator training and licensing and will be the agency that enforces compliance with a pesticide label and investigates cases of pesticide misuse. In addition to these entities that have oversight over pesticides and how they are regulated, there are a number of others that regulate pesticide use, both on the state and the federal level and that includes Departments of Ecology, Departments of Fishery, and Fish and Wildlife Departments of Labor and Relations. Slide 18 This information was provided to me by the Washington State Department of Agriculture

6 in their investigations of Ag-related illness caused by pesticide exposure. I like to show this as a little pie chart to indicate that the risk of exposure to pesticides is greatest to those who mix and apply these pesticides. In this particular slide, nearly thirty-nine percent of Ag-related illnesses caused by pesticides was incurred by the applicators themselves. Now for homeowners and for those people who are not involved in commercial Ag, the most common form of accidental non-occupational exposure is to pesticide drift. And so I just wanted to show this to keep in mind that the person who is most at risk of pesticide exposure are those of us who mix and apply these pesticides. We are dealing with a concentrated formulation of that pesticide product; we are the people who need to take the greatest care in using and applying these pesticide products. Slide 19 The number one safety tip that I can give to you in utilizing and using pesticides to control pests in a home garden or home situation is to read the pesticide label. And you want to read the label when you're in the store before you buy the product, you want to read that label again before you mix the product, and again before you apply that product. There'll be information on that label that tells you how to best store that product and tells you how to dispose the container or the pesticide residue after you're through with its use. So always read the pesticide label. And if you happen to go out and buy the same pesticide year after year please take note that these pesticide labels, even for the homeowner can change from year to year. Slide 20 Now we're going to go through and look at the various components of labels associated with pesticides. One of the first things you'll see is that every pesticide has a unique product name. In this case we are looking at a product called Safer Caterpillar Killer. Another type of pesticide we might encounter, another brand of pesticide we might encounter, is a product with the unique name Weed B Gone. What I'd like to do now is go through pesticide labels and point out to you some of the important information that is on those labels, the various components that make up a pesticide label. And of course the first information that is on a pesticide label is a pesticide name, product name, and pesticide type. The first product that we have pictured here is a product known as Safer Caterpillar Killer. Obviously this is going to be an insecticide with the unique name of Safer Caterpillar Killer. Under that is a product known as Ortho Weed B Gone. Again, this is a unique name of a product which is obviously a herbicide. Another rather unique type of product is a product called Surround-at-Home Crop Protectant. Now it's a little difficult to determine what exactly this product is but it is an insecticide that disguises the apple so the insects don't find it. It's really not a toxic product, which is probably why they refer to it as a crop protectant rather than an insecticide. Slide 21 All pesticide labels must list the active ingredient or the actual compound or chemical

7 that is the toxic agent in that product. This is one of the sample products that I took a picture of and it is actually a Lysol product, a disinfectant. The active ingredient in this is listed as sodium hypochlorite which we might recognize better as bleach. All pesticide labels must list the active ingredient that is in the product we are using. This other label is from a Bayer Advanced label for rose and flower care and we see on this that the active ingredient in this product actually is disulfoton, which is in a very low percentage but is the active ingredient, the toxic ingredient in this pesticide product that is effective against aphids and other sucking insects. Now in this pesticide product listing we will also see the inert or other ingredients are listed. These are chemicals or products in the formulation that aren't the ingredients or products that are actually toxic to anything. These ingredients may include things like surfactants, UV or ultraviolet protection agents, spreaders/ stickers - products that reduce the amount of drift or foaming when these insecticide products are mixed up. Often the most common inert ingredient is water. Slide 22 Pesticides can come in different formulations, even for homeowners. They can be emulsifiable concentrates, which are liquid formulations that you can add water to before you apply them. They may be in the form of wettable powders, which again are products you can add water to, disperse the powder and then apply it through spray. Pesticides can also come in the form of granules and in this picture the rose and flower care product is in the form of a granule material. They may also come in the form of dusts, such as this product that is applied for control of fleas, cats and dogs. They may also be in the form of aerosol sprays. Slide 23 Another integral part of a pesticide label are the signal words, which give you an indication of how toxic the product is to humans and pets. Now remember, a pesticide is a product which kills and so all pesticides are toxic to something. One general warning that you'll see on all pesticides is the warning to keep out of reach of children. This is on all pesticide products. Because remember, all pesticides are toxic to something, some organism, and it's just common sense to keep these products out of reach of children, including any household disinfectants you might have in your cabinets. Slide 24 Signal words are words that give the homeowner an idea of how toxic a pesticide product really is. Most of the products that homeowners have will either say Caution or Warning. Caution is a signal word that tells you that this product, the ingredient in this pesticide product, is slightly toxic or hazardous. The signal word Warning means that the product, the active ingredient in the pesticide product is moderately toxic or hazardous. Very few products that homeowners have access to will have the signal word Danger, which means this product is very hazardous either to the eyes or by

8 contact through the skin. And of course, everyone should be familiar with the Danger poison signal word, which indicates with a skull and crossbones symbol that the product is extremely toxic if ingested. Slide 25 Another component of a pesticide label is the Directions for Use. These directions are going to tell you where and when this pesticide product can be used. It can tell you what crop it can be used on and what site it can be used in. On this label you can see that it tells us that we can use this product on outdoor ornamentals only. Within the Directions for Use you will also information that tells you what the proper dose is to use of that product and it may also give you some instructions on how best to mix and what type of equipment to use to apply the pesticide product that you are using. In the Directions for Use you will also find what the target pest of that product is. In this case we are looking at a product that targets aphids, leafminers, elm leaf beetles, leafminers, lacebugs, leafhoppers, spider mites, thrips, and whiteflies. Other information that might be on the label if pertinent is re-entry interval, which tells you how long you must wait after you've applied a pesticide product to re-enter that area. Most of the products that homeowners have, that re-entry time is in a matter of hours, allowing that pesticide product to dry. You might also see on a Directions for Use a pre-harvest interval, which is that interval from the time you apply a pesticide until the time you can harvest that crop for consumption. Slide 26 Another critical component of a pesticide label is the Statement of Practical Treatment. This is a statement to tell you what to do if the product, the pesticide product, is accidentally inhaled, swallowed, or comes in contact with the eyes, or has made contact through the skin or clothes. Slide 27 So included within the Statement of Practical Treatment you will also find a note to physician, and these are directions for the physician to tell that physician how to best handle an accidental poisoning. So if this does happen, always be sure to have that label handy nearby when you call in to a pest poison control center or to your physician. And if need be, bring this product label with you to show the physician in the emergency room. Slide 28 Another component that you'll find on a pesticide label are the Precautionary Statements. These will outline the hazards to humans and to domestic animals. These hazards might be hazards to eyes, to skin, or hazards for ingestion. These labels will usually give you some indication of what the proper clothing is to wear, and the other Precautionary Statement you might find on a pesticide label is instructions on how to

9 wash clothing or hands or other hygiene issues associated with the use of the pesticide product. Slide 29 Underneath the Precautionary Statements you will also find an Environmental Hazards Statement, which often indicates how toxic this product is to certain organisms in our environment such as bees, birds, fish, or aquatic invertebrates. In this case we're looking at a label that says that this product is extremely toxic to birds, mammals, fish, and aquatic invertebrates. Slide 30 You will also find on a pesticide product label instructions for how to best store and dispose of the pesticide product and the container that they are in. Some general rules of thumb that we have for pesticide storage is to reduce or eliminate access to the product by children and pets. Keep your pesticides stored in a locked cabinet that is off the ground. You want to keep these pesticide products in a well-ventilated, dry area. Another general rule of thumb is never flush pesticides down the sink or toilet, and do not put pesticide products in the garbage. And when you're through using a pesticide product, it's often important to triple rinse those empty containers and never, ever reuse those empty containers for anything else. Slide 31 One other important thing to keep in mind when you're using pesticide products is that help is only a phone call away. So it's nice to have these particular numbers handy nearby when you're using a pesticide product, just in case. And the first number listed here is the National Poison Emergency Center. It's a number and remember if you do call in to that to have that pesticide label handy nearby because that pesticide label is going to give the National Poison Emergency Center a product name, an active ingredient, as well as information on how to best contain the emergency. There is also a number here for the National Pesticide Information Center and this is not for emergencies, but it is still a very important source of pesticide information and is a number as well. Another number to keep handy nearby is the Washington State Department of Ag and this is the number for the Pesticide Compliance and Licensing Department. Slide 32 Now what I'd like to do is talk a little about the Master Gardener diagnostic clinic. The Master Gardener diagnostic clinic is a key service provided by our WSU Master Gardener volunteers. The clinic is where community members will bring in samples, pest samples, or stressed plant samples into the clinic. One of the key focuses of the Master Gardener program is to train you in how to assist in plant and pest diagnoses.

10 Slide 33 Most of our Master Gardener diagnostic clinics are supplied with a very good reference library of bulletins and other materials that have been prepared by WSU faculty. Master Gardeners also have access to some of these WSU faculty with the expertise to make the diagnoses. A lot of our clinics have microscopes and a digital diagnostics web page which they can use to help them make the diagnoses of these samples brought into the clinic. Some of the tools that they will have in helping them make the diagnostics is some paperwork that's prepared to walk a Master Gardener through the process of trying to identify what is causing the problem or the pest. Slide 34 In addition to the reference library one of the more invaluable sources of information for the Washington Master Gardeners can be found on the website at this particular website address. The website is known as Hortsense, and this Hortsense website is a collection of home gardening fact sheets to help home gardeners manage plant problems. These fact sheets advocate the integrated pest management approach to pest management. It begins by talking about cultural controls that are available to home gardeners as well as the pesticides that are actually registered here in the state that homeowners can use to control horticultural pests. And the nice thing about this website is that it is updated every year. Slide 35 Linked to Hortsense is another invaluable source of information, a website called Pestsense. Pestsense is a collection of fact sheets for managing the common indoor pest problems. Like Hortsense, it's based on integrated pest management or IPM. Cultural tactics will be listed first as well as biological control, physical control, mechanical control, and last but not least, a listing of pesticides that Washington homeowners can use to control common pest problems found indoors.