三、JHandJHAJuvenile Hormones (JH)MostcurrentlyregisteredIGRs,suchashydropreneandmethroprenefall into the juvenile hormone mimic categoryThesepesticidesmimictheJHproducedintheinsectbrain,whichforcesthe insectto remain ina juvenilestate.Normally,theproductionoftheJHwouldebbastheinsectprogressedthroughthenymphalstagesuntil thefinalmolt intotheadultstage,whenJHproductionwouldcease.WhenexposedtoaJHmimic,theinsectremainsinanimmaturestateandisrenderedunableto successfullymolt intotheadultstageorbecomereproductivelyviableJHmimicsarenotbespecifictothepestunderattack,asthemoleculesbasedontheJH systemaremoreorlesscommontoallinsectspecies◆Most currently registered IGRs, such as hydroprene and methroprene, fall into the juvenile hormone mimic category. ◆These pesticides mimic the JH produced in the insect brain, which forces the insect to remain in a juvenile state. ◆Normally, the production of the JH would ebb as the insect progressed through the nymphal stages until the final molt into the adult stage, when JH production would cease. ◆When exposed to a JH mimic, the insect remains in an immature state, and is rendered unable to successfully molt into the adult stage or become reproductively viable. ◆JH mimics are not be specific to the pest under attack, as the molecules based on the JH system are more or less common to all insect species. Juvenile Hormones (JH) 三、JH and JHA