INSECTICIDES Flashcards
Insecticides
Key to selecting an insecticide for an IPM program is identifying the species causing the damage, determining the life stage most effectively controlled, and timing the application for that window of opportunity.
Contact Poison vs Stomach (systemic) Poison
1.) Provides control when the target pest comes into physical contact with the insecticide.
2.) Must be ingested in order to affect the pest.
(If application is made to the tops of leaves and insect feeds on the underside, then there may not be any affect, unless the insecticide is systemic).
(Sometimes quantity can be an issue for systemic insecticides, if the insect only consumes the plant superficially whereas the active materials predominantly resides in the cambium).
N-methyl carbamates and Organophosphates
Disrupt nerve activity and are toxic to a broad spectrum of animal species.
Most widely used class of insecticides since the 1970’s.
Seen a decrease, partly because of toxicity to people and non-target organisms.
Pyrethroids
Includes resmethrin, permethrin, fluvalinate, and other compounds. Plant derived insecticides.
Disrupt nerve activity, stimulating nerve cells, and eventually cause paralysis. Are generally effective at much lower rates than organophosphate materials.
Neonicotinoids
An expanding chemical class. Nerve posions with a similar site of action as nicotine. Many of these materials are systemics include-imidacloprid, dinotefuran, acetamiprid, and thiamethoxam. Broadly toxic against arthropods.
Debate over the affect it has on bee populations.
Organochlorines.
Very few organochlorines continue to be in use throughout the U.S.A. today due to negative impacts on wildlife, from persistence and toxicity. Some well known materials included DDT, chlordane, aldrin, dieldrin, endrin, mirex, and toxaphene.
The two remaining insecticides from this class are; Endosulfan and Lindane: both of which are restricted uses pesticides.
Insect Growth Regulators (IGR’s)
Are synthetically produced chemicals used to interfere with an insects normal development. Some inhibit development through mimicking insect hormones or inhibition of hormonal production (ex: chitin inhibition to disrupt skeletal formation during molting).
This can include disruption of egg or larval production.
This includes hydroprene (cockroaches), pyriproxyfen (fleas and scales) and diflubenzuron (caterpilars).
Microbial Insecticides
Arise from microorganisms that cause disease in insects deeming them immobile.
Most commonly available is Bacillus thuringiensis (Bt) and are available to control moths, butterfilies, mosquitos, and fungus gnat.
Insect life cycle
Gradual/incomplete/simple metamorphosis
vs.
Complete metamorphosis
Insect pest are usually easier to manage during one or two of their life stages vs. others.
Pesticides may not be effective against certain stages.
Gradual/incomplete/simple metamorphosis
3 stages- egg, nymph, and adult
- wings become fully developed only in the adult stage.
Complete metamorphosis
4 stages - egg, larva, pupa, and adult
