© 2011, 2007, 2002, 1988 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 Practical Horticulture 5 th edition By Margaret J

© 2011, 2007, 2002, 1988 Pearson Education, Inc.Pearson Prentice Hall - Upper Saddle River, NJ 07458

Practical Horticulture 5th edition By Margaret J. McMahon, Anton M. Kofranek and Vincent E. Rubatsky

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Chapter 15 - Integrated Management of Weeds, Insects, Diseases & Other Pests

Insect & Mite Pest ManagementInsect & Mite Pest Management

• Pest managers rarely use the term pest control or eradication—because we have never been ableto control insect and mite pests permanently.



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Insect and Mite Pest Management - Modes of EntryInsect and Mite Pest Management - Modes of Entry

• Stomach poison refers to materials that enter by mouth & kill absorbtion via the digestive tract.

• Some insecticides can be absorbed into plant tissues (translaminar systemic) and/or transported through vascular systems (translocated systemic).

• Systemic insecticide residues can remain in the plant tissues eaten by humans.



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Insect and Mite Pest Management - Modes of EntryInsect and Mite Pest Management - Modes of Entry

• Contact poison refers to materials that enter the body directly through the pest’s cuticle.

• Some have to be applied to the pest—others have sufficient residual action that residues are pickedup as the pest walks across treated surfaces.

• Inhalants are applied as fumigants, and inhaled as a vapor or dust by the insect or mite.

• Fumigants are generally used in enclosed spaces.– Some can also be used in soil if the surface is sealed with

water or an impermeable covering like plastic sheeting.



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Insect and Mite Pest Management - Modes of ActionInsect and Mite Pest Management - Modes of Action

• Neural Disruption—major neural systems affected are sodium pump channels & neural transmitters.

• Cellular Metabolic Disrupters—disrupt different metabolic pathways of a cell.



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• Cell Membrane Disruption—oils & soaps disrupt the lipoprotein matrix of cells, causing them to lose their contents and cease functioning.

• Though considered impermeable, the insect cuticle is filled with microtubules that lead to the underlying cells—which are destroyed by oils and soaps.



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• Hormone Disruption—pesticides can mimic insect hormones or disrupt normal function of hormones.

• These are called insect growth regulators (IGR).

• Many of these have specific targets, which makes them safe to use for predatory insects & mites.



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• Pheromones—chemicals insects normally use to communicate with each other—can used to disrupt mating.



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• Dessicants—cause insects to lose water faster than they can replace it.

• Desiccants work best in dry environments.



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Insecticides Classified by ChemistryInsecticides Classified by Chemistry

• A great many chemicals have been used for controlling insects—– Some were so harmful to humans, animal life, and

the environment that their use is no longer permitted.

• In the U.S. insecticides must be approved/registered by various agencies before they can be used. – Use is confined to certain plants, times & concentrations.

• Residues on food or feed crops exceeding fixed tolerances subject products to seizure & destruction.



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Insecticides Classified by Chemistry - InorganicInsecticides Classified by Chemistry - Inorganic

• Inorganic compounds—arsenic, phosphorus, fluorine and sulfur compounds. – Use of these has diminished greatly over time.



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Insecticides Classified by Chemistry - OrganicInsecticides Classified by Chemistry - Organic

• Organic compounds—Plant derivatives like pyrethrum, rotenone, nicotine, and an extract from the neem tree. – Others could possibly be developed, given sufficient

demand.



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• Synthetic organic chemicals.– Chlorinated hydrocarbons such as DDT, discovered in

Germany in 1874.

– Organic phosphates, developed near the end of WW II, found to have good insecticidal properties.

– Carbamates—Carbaryl was first widely-used—with low mammalian toxicity & short residual action.



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• Synthetic organic chemicals– Pyrethroids—fairly new class of insecticides that mimic

properties of pyrethrins such as low mammalian toxicity.

– Neonicotinyls—a recent class of insecticides that blockthe synoptic transmission of insect nerves.

– Spray oils—prepared by distillation/refining of mineral oils, an oil fraction relatively nontoxic to plants, lethal to insects.

– Microbial insecticides—some insects are susceptible to certain toxins produced by bacteria, fungi, and viruses

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© 2011, 2007, 2002, 1988 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458 Practical Horticulture 5 th edition By Margaret J