Comparative testing of several juvenile hormone analogues in two species of locusts, Locusta migratoria migratorioides and Schistocerca gregaria
✍ Scribed by Pener, M. Paul; Ayali, Amir; Kelmer, Gal; Bennettová, Blanká; Němec, Václav; Rejzek, Martin; Wimmer, Zdeněk
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 252 KB
- Volume
- 51
- Category
- Article
- ISSN
- 1526-498X
No coin nor oath required. For personal study only.
✦ Synopsis
E †ective treatment with juvenile hormone analogues (JHAs) of early penultimate or early last-instar locust hoppers induces a supernumerary "extraÏ nymphal instar. These "extraÏ nymphs, also termed "adultoidsÏ, die in the course of, or shortly after, an "extraÏ moult. Less e †ective treatment results in imperfect adults with crumpled twisted wings which presumably limit their Ñight and migratory abilities. Extremely e †ective treatment leads to death in the next moult. Comparing dose-response relations of (7S)-methoprene, fenoxycarb, pyriproxyfen and a new JHA, R70-1 (ethyl cis-N-M2-[4-(2-hydroxycyclohept-1ylmethyl)phenoxy]ethylNcarbamate), we revealed that route of administration, instar of the recipient hopper, and species may alter over 1000-fold the for ED 50 the same JHA. L ocusta migratoria migratorioides is much more susceptible to JHAs than Schistocerca gregaria. The lowest found to induce adultoids ED 50 and subsequent death in the "extraÏ moult was 0É12 kg pyriproxyfen injected in olive oil to early penultimate instar hoppers of L . m. migratorioides (about 0É5 kg g~1 fresh weight). R70-1 was more active than pyriproxyfen following the more practical topical application to early last-instar hoppers of L . m. migratorioides, 5É9 kg and 46 kg per hopper, respectively (about 10 kg g~1 and 78 kg g~1 fresh weight). The high susceptibility of last-instar L . m. migratorioides nymphs to topically applied R70-1 is promising from the practical standpoint.