Final Exam: Insecticides Flashcards
insecticides are
substances used to control insects
3 types of insecticides
adulticides, larvicides, ovicides
types of nerve poisons and their corresponding numbers
synaptic poisons - neurotransmitters-chemical and receptors (1,5)
axonic poisons- (action potential-electrical) channel blockers (2,3)
physiological poisons - IGRs (7); microbial gut disruptors (11); chitin synthesis disruptors (17)
group 1 insecticide
synaptic poisons - chemical messengers; quick breakdown; broad spectrum
group 2 insecticides
stable; medium to high mammal toxicity; cattle ear tags
group 3 insecticide
major group- last longer; stable; medium spectrum; low to medium mammalian toxicity; quick knockdown
group 5 insecticide
limited spectrum (flies and lice) fermentation products produced by a soil bacterium; rapid degradation in sunlight; low mammalian toxicity
how do nerve poisons kill insects?
paralysis; dehydration; starvation
group 6 insecticides
fermentation products produced by a soil bacterium - active against some insects, ticks, and roundworm intestinal parasites
group 7 insecticides
insect growth regulators
group 11 insecticides
microbial gut disruptor - stomach poison
control of mosquito and black fly larvae
group 17 insecticide
chitin synthesis inhibitor larvadex in feed or manure spray
treated pupae are more slender and elongate
***which order has the greatest # of resistance of the most insecticides?
diptera
resistance has been a growing problem since
1950 - about the time insecticides started being used
multivoltine
have several generations in a year
4 main types of resistance
*metabolic
*target site
behavioral
reduced absorption
metabolic resistance
detoxify insecticide - greater amount or more efficient
target site resistance
prevents binding - wont let ions go through channel
behavioral resistance
hyper-irritable response - avoidance of treated surfaces; group 3: pyrethroids –> irritating and don’t pick up enough to be killed b/c they leave so quickly
reduced absorption
slower uptake - often paired with another factor - exoskeleton prevents it from entering as well
resistance
decreased susceptibility of a species to a class(es) of insecticides
cross resistance
individuals resistant to one class of insecticides also are resistant to members of another class, even though they have not been exposed to it
confirming resistance
timed exposures; specific doses; enzyme/genetic studies; compare to susceptible population
why are horn flies resistant
amount of time on host; short life cycle (lets the resistant individual build up in #’s); high use of sustained release insecticidal ear tags; limited insecticide types in ear tags - less rotation (build up resistance; applying tags too early or not removing tags at en of season
