Herbicides are what we use to kill unwanted plant life in yards and commercial landscapes. If you are confused about what a technician means when they mention using a pesticide, you can ask them to break it down into one of these categories. There are many different types of herbicides. Certain herbicides are also designed to only kill specific plants. These are called selective herbicides. We use these in areas where you may want to kill weeds while allowing grass and other desirable plants to thrive.
Non-selective herbicides kill everything they contact. Herbicides also have different effects depending upon which part of the plant growth process they target. Post-emergent herbicides kill weeds that are already maturing into visible plants. Whether you are using an insecticide or herbicide, it is important to use caution. Most preparations use chemicals to accomplish their mission, and these can have the potential to harm humans and animals. It is also important to use the right type of pesticide for the job.
Herbicides will typically have no real effect upon rodents. Professional treatments eliminate the chance of using the wrong pesticide by mistake. Post-emergence herbicides are applied to weeds that are already growing, but they're most effective on young weeds. A third category of herbicides is selective versus nonselective. Selective herbicides only affect certain types of plants, but nonselective herbicides are harmful to most plants.
The types of plants affected by selective herbicides are usually either grasses or broad-leaved plants, and the herbicides may work preemergence or postemergence of the weeds.
Some pesticide labels look like a meaningless jumble of numbers, letters and confusing words. They contain so much information because they're legal documents, but also because they convey essential information to the consumer. Some important items you can expect to see on a product label are:. The product type tells you what pest the pesticide controls, and the active ingredient is the name of the chemical or chemicals that affect the pest. Signal words are words like danger, poison and caution, and, along with the precautionary statement and hazards, they warn you of the potential unintended harmful effects and dangers of using the product.
If the pesticide accidentally comes into contact with a person, the first aid or practical treatment statement gives information on how to immediately treat that person. Finally, the directions for use, storage and disposal should be followed closely because they tell you how to use, store and discard the pesticide safely.
A graduate of Leeds University, Jenny Green completed Master of Arts in English literature in and has been writing about gardening and homes since Green's work appears in SFGate, Mom. By Jenny Green Updated October 23, Related Articles. Synergists make certain pesticides more effective, but they are not effective when used alone. Treated Seeds are coated with a pesticide to limit crop damage from fungus and insects. Wood Preservatives are used to make wood resistant to insects, fungus and other pests.
If you have questions about this, or any pesticide-related topic, please call NPIC at am - pm PST , or email us at npic ace. NPIC provides objective, science-based information about pesticides and pesticide-related topics to enable people to make informed decisions.
Environmental Protection Agency cooperative agreement X The information in this publication does not in any way replace or supersede the restrictions, precautions, directions, or other information on the pesticide label or any other regulatory requirements, nor does it necessarily reflect the position of the U.
Several examples of pesticides available for backyard plantings are described below. Since various suppliers provide the same active ingredient under various trade names, the compounds below are listed using their common chemical name. Not all insects or diseases appear on all labels for all crops. Always consult the label before making pesticide applications.
Labels vary greatly between commercial products of the same material. It is important to refer to the label for the best timing and application rates when applying pesticides. Table 2. This azadirachtin-based biological insecticide, repellent, antifeedant, and insect growth regulator is used mostly in soft, organic insect-control programs.
It controls pests on contact and ingestion. Azadirachtin can be applied using standard spraying equipment up to the day of harvest. This pesticide is toxic to fish and aquatic invertebrates. Bacillus thuringiensis Bt--many products is a selective microbial insecticide formulation using a byproduct of the naturally occurring bacterium Bacillus thuringiensis as its active ingredient.
This bacterium is able to exist as a spore until temperature, moisture, and available nutrients are conducive to the reinitiation of the life cycle.
Bt exhibits a unique insecticidal activity when eaten by susceptible larvae, specifically those of the insect order Lepidoptera moths and butterflies. Bt does not have any of the hazards sometimes associated with chemical insecticides. It has been shown to be incompatible, however, with mixtures with a high pH such as Bordeaux mixtures. In orchards, Bt should provide excellent control of variegated leafroller, tufted apple bud moth, red-banded leafroller, oblique-banded leafroller, green fruitworm, and most forest-orchard species gypsy moth, tent caterpillar, webworm.
If mixing Bt with other products, always add Bt first. Good mechanical agitation is important to quickly mix Bt. Captan is a fungicide with protective and curative action. Many of the general purpose product mixes contain captan see Table 2. Captan is effective against scab, black rot, white rot, bitter rot, Brooks spot, and blossom end rot on apples.
It is effective against sooty blotch and flyspeck if the last spray application is not more than 30 to 40 days before harvest.
It is not effective against the rusts, fire blight, or powdery mildew. Where the early season apple scab control program fails and scab becomes established in the trees, captan at low rates cannot be expected to provide control.
This fungicide is highly effective, however, in reducing spore germination. Use at least 4 to 5 T per 2. On stone fruits, captan is a good fungicide for the control of brown rot and scab when adequate spray schedules are followed. Captan plus wettable sulfur can be used on peaches when brown rot, scab, and mildew are present. Captan is effective against cherry leaf spot and brown rot on tart cherries if the diseases are at a low level and the spray intervals do not exceed 2 weeks.
Captan has caused a necrotic spotting, yellowing, and dropping of leaves when used under poor drying conditions or in combination with sulfur, especially on Delicious, Stayman, Baldwin, and King apple varieties. Foliage of d'Anjou pears has been stunted and cupped. Necrotic spots on fruit and foliage have occurred on both plums and prunes where captan was used from petal fall until the fruit begins to ripen.
Its use usually results in acceptable fruit finish on apples, peaches, and nectarines. Captan residues on peaches at harvest may cause increased skin discoloration from abrasions that occur during picking and packing. The leaves of some sweet cherry varieties may be injured by repeated captan applications. A full-season program of captan may require the use of miticides or close adherence to a pest management program.
Captan is not registered on pears. Captan has few spray incompatibilities, but it should not be used with oil, lime, or other alkaline materials. Using captan within a week either before or after an oil application may result in leaf injury on apple trees. Combinations with sulfur might result in increased injury under high temperatures and high relative humidity. The preharvest interval for captan is 0 days. Please remember to check the label for rates and application times for best disease control.
Carbaryl Sevin is a relatively safe, carbamate insecticide. It is highly toxic to bees and should not be used near bloom. When applied 2 to 3 weeks after bloom, carbaryl acts as a fruit thinner on many varieties.
Mite populations usually build up rapidly following carbaryl applications because of its toxicity to mite predators. Thus, it is not recommended for most applications where mites are a threat. Chlorothalonil formulations are nonsystemic foliar fungicides with protective action registered for the control of brown rot blossom blight; leaf curl of stone fruits; scab on peaches, nectarines and apricots; and cherry leaf spot.
There are many formulations of chlorothalonil available to the home gardener see Table 2. Copper compounds are widely sold as fungicides for orchard and garden use. Copper is a foliar fungicide with protective action. These compounds can be highly phytotoxic to many fruit crops and must be used with extreme care. Check the label for type of copper and any cautions that accompany its use.
Please remember to also check the label for rates and application times for best disease control. Many formulations of copper are available to the home gardener see Table 2. Copper was first used in the mids in grape vineyards in France to discourage theft of the grapes. Copper sulfate and lime were mixed in a slurry and spread over the grape vines.
In a French scientist observed that this antitheft treatment was effective in reducing a disease called downy mildew. This observation was made near the town of Bordeaux, so the mixture of copper sulfate and lime became known as Bordeaux mixture. Copper sulfate is readily soluble in water. This high degree of solubility is the fundamental cause of the toxicity problems, which copper sulfate can cause to all fruit crops. Fixed coppers have been developed that are relatively insoluble and therefore less toxic to plants; however, fixed coppers can also result in phytotoxicity under certain conditions.
Fixed coppers include basic copper sulfate, basic copper chloride, copper oxides, and copper hydroxide. The fungicidal activity of copper is based on its ability to destroy proteins in plants. This is true for all plants, fungi, and fruit plants. When lime is combined with copper compounds, it reacts with the copper, making it more stable. Thus, copper compounds in the presence of lime would generally produce lower, more uniform concentrations of free copper, which in turn would be less apt to injure plant tissues than if no lime were used.
Because copper has the ability to kill all types of plant tissues, the use of copper fungicides carries with it the risk of causing injury to fruit plants. Ideally, copper on the leaf or fruit surface should be in high enough concentration to kill the fungus or bacteria but low enough not to cause injury to the plant.
Factors that can promote injury include failure to use enough lime; cold, wet weather conditions that apparently increase copper's solubility, allowing more into the plant and resulting in toxicity; and application of excessive rates of copper. Even when no injury is evident on the plant, subtle effects of the copper on the plant may be occurring. In addition, to reduce growth and yields, it has been shown that the use of copper fungicides can reduce the maturity of the fruit as well as that of the shoots.
Copper fungicides can have subtle, chronic negative impacts on fruit plants. Copper will provide low to moderate control of many of the diseases. Fixed coppers, plus lime, are safer than Bordeaux. They may be used for leaf curl control on stone fruits and pre- and postharvest leaf spot control on tart cherries.
These compounds are useful in plant nutrition since they supply copper to the plant. Strawberries are very sensitive to copper. Never apply copper to strawberries because severe phytotoxicity will result under almost any conditions.
Do not apply any of the copper compounds without adding lime. Lime should be used at a rate one to two times that of the copper. If a copper material is applied without lime and yellowing and leaf drop occur, an application of lime within 2 to 3 weeks of the copper application may prevent further yellowing and leaf drop. Again, check the label of the product you intend to use to see if lime has already been added in the formulation or if it is advised to add lime and at what rates.
Do not use copper in cool wet weather. Do not use immediately before or after using ferbam. Most insecticides are not compatible with lime. Esfenvalerate is a broad-spectrum pyrethroid insecticide with contact and stomach action. Esfenvalerate is very toxic to fish and other aquatic organisms.
Esfenvalerate is also highly toxic to bees exposed to direct treatment and residues on plants. Use recommendations are generally limited to before bloom in Pennsylvania to conserve Stethorus and other predators of European red mite. Do not feed pomace to livestock. Ferbam Carbamate is effective on apples for rust and scab control, on stone fruits for leaf curl, on cherries and plums for clear spots and black knot, and on pears for leaf and fruit spot control.
Do not use with lime. Ferbam may produce unsightly residues on leaves and fruit. On Golden Delicious, Jonathan, and other varieties that russet easily, injury may result from using ferbam, especially if it is applied in the pink through mid-June.
The best time to use it is in the prepink period or in later summer sprays after mid-June. A 10 percent formulation of garlic is registered on apples and a number of apple pests are on the label. However, during the studies conducted at the Cornell University, no efficacy was observed when the compound was applied to control fruit pests listed on the label. General purpose products GP-Products vary depending upon the manufacturer.
Generally, the products will contain both a fungicide and an insecticide mixed in appropriate ratios for general control of most diseases and insects see Table 2. Glyphosate RoundUp is registered for use on apples and pears up to 14 days before harvest and in stone fruit orchards up to 28 days before harvest.
It is effective in controlling many emerged annual and perennial grasses and broadleaved weeds. Best results occur when it is applied as a 2 percent solution. It is labeled as a directed spray on apples and pears.
In stone fruits it must be applied through a wick applicator. Glyphosate has no preemergence activity; therefore, it should be combined with a preemergent material for residual activity. Caution: Avoid all contact with tree foliage. The chemical is not readily metabolized by plants, and accidental coverage could cause injury the following year. Glyphosate should not be stored or applied in galvanized steel or unlined steel except stainless containers or tanks.
It can react with these containers to produce highly combustible hydrogen gas mixtures. The naturally occurring codling moth granulovirus belongs to the subclass B of the baculoviridae.
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