Selected combinations of (Z)-5-decenyl, (Z)-7-dodecenyl, and (Z)-9-tetradecenyl acetates, the pheromone components of the turnip mothAgrotis Segetum were tested for field attractancy at six, two, and three sites in Europe, Asia, and Africa, respectively. At all of the sites in Eurasia and in northern Africa the ternary mixture of the acetates captured most males, while at the sites south of the Sahara in Africa, (Z)-5-decenyl acetate alone was responsible for attraction. Differences in male attraction among the populations studied confirm the existence of significant population variation in the pheromone ofA. segetum. Interpretation of the present results together with earlier studies suggests that this variation is more or less continuous in Eurasia and north Africa, while a clearly distinct pheromone type is present in the areas south of the Sahara desert.
Four compounds, tetradecyl acetate, (Z)-9-tetradecenyl acetate, (E)-11-tetradecenyl acetate and (Z)-ll-tetradecenyl acetate were identified from female sex pheromone extracts of Hungarian and Egyptian lima-bean pod borers (Etiella zinckenella Tr., Lepidoptera: Phycitidae) by gas chromatography with flame ionization (FID) and electroantennographic (EAD) detection. In EAG studies these monounsaturated acetates gave the best responses in a series of other tetradecenyl acetates and tetradecenols. The four component blend of the identified components in similar ratios as in the pheromone extract attracted significant numbers of male lima-bean pod borers in both Hungary and Egypt. In a preliminary subtraction test best capture was achieved by the ternary mixture of the monounsaturated acetates.
Fluoromevalonate (FMev, ZR‐3516) known as an inhibitor of JH biosynthesis was topically applied in 0.1 to 50 μg/specimen doses to the 3rd, 4th, and 5th instar caterpillars of Hyphantria cunea Drury. The anti‐JH compound induced 3 main types of specific responses: 1) precocious metamorphosis, 2) inhibition of ecdysis, and 3) prolongation of larval development. Precocious pupation was accompanied by behavioural events typical of normal pupation. Third and 4th instar larvae metamorphosed prematurely mostly with the intervention of an intercalary larval instar. The 5th instar exhibited the highest sensitivity to the anti‐JH agent. Within each larval stage the freshly moulted insects proved to be the most susceptible to FMev. Afterwards, the incidence of morphogenetic reaction gradually decreased with age. In another fraction of Hyphantria larvae not responding with precocious pupation, FMev evoked varying degrees of ecdysial disturbance which always resulted in the death of caterpillars. In most cases the anti‐JH compound inhibited the premature pupal moult, too, and these affected insects died as tanned pharate pupae. A complete or partial “rescue” from the effects of FMev was elicited, if simultaneously or subsequently, a single topical dose of a JH analogue, hydroprene was also administered.
M. R. Abo‐Elgar, Monoufia Univ., Shibin El‐Kom, Egypt, on occasion of his 60th birthday.
ZUSAMMENFASSUNG
Induktion verfrühter Metamorphose und gehemmter Häutung durch FMev, eine Verbindung mit Anti‐Juvenilhormon‐ Wirkung beim amerikanischen weissen Bärenspinner, Hyphantria cunea
While Insegar and the sulfenylated carbamate juvenoid NKI‐43049 totally inhibited the egg production of Carulaspis juniperi (Hom., Diaspididae), only approximately 1% of the Applaud or NKI‐35120 treated females laid eggs. Applaud and the sulfinylated carbamate derivative NKI‐35120 resulted a very low egg‐production (16% and 4% of the untreated control, respectively). Importantly, the tested fenoxycarb‐related compounds did not reduce the rate of parasitization caused by Aphytis mytilaspidis (Hym., Aphelinidae), Applaud, however, had a moderately adverse effect on it.
NKI‐35120 gave an excellent result at a concentration of 0.1 a.i.% on Lepidosaphes beckii (Hom., Diaspididae). Insegar (0.1 a.i. %) and Applaud (0.05 a.i%) had good activity as well. Males were more sensitive than females for the treatments. NKI‐35120 and Insegar strongly reduced the egg production of the females. The treatments did not reduce significantly the rate of parasitization caused by Aphytis lepidosaphes (Hym., Aphelinidae).
NKI‐35120 and Insegar at a concentration of 0.025 a.i. % strongly affected Ceroplastes japonicus (Hom., Coccidae) development since none of the treated larvae could develop to female. Surprisingly, Applaud had only moderate affectivity on C. japonicus.
AbstractThe chromene derivative precocene II (1) induces precocious metamorphosis and sterility on some insects, while β-asarone (2), which does not contain a chromene ring, reveales sterilant action without causing developmental disturbances. Based on the common structural features of these two substances, some of their analogues containing their structural elements have been prepared and tested on the cotton bug, Dysdercus cingulatus to investigate structural requirements of activity. The title compound 3 lacking the chromene ring induced symptoms similar to those of precocene II, indicating that the chromene ring structure is not necessary for this action.
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