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.
The searching rate of the two aphelinid parasitoids, Eretmocerns mundas Merc. and Prospaltella lutea Masi, and the two predators, Chrysoperla carnea Steph. and Coccinella undecimpunctata L., were evaluated on Bemisia tabaci in the laboratory. Analysis of the obtained data indicated that E. mundus had a high searching rate with relatively low mutual interference in comparison with P. lutea. C. carnea also showed a higher searching rate than C. undecimpunctata. E. mundus exhibited a higher density dependent response to B. tabaci population on Lantana camara than P. lutea in October and December, while P. lutea exhibited the same response in August. Key factor analysis proved that the first instar larvae had the highest rate of mortality among the immature stages. Mortality caused by E. mundus contributed with high fate of total generation mortality ( K ) in comparison with P. lutea. The same result was obtained in the case of C. carnea against C. undecimpunctata.
Fenoxycarb, hydroprene, kinoprene and methoprene have been sprayed on Epidiaspis leperii and its ectoparasitoid, Aphytis mytilaspidis. These juvenoids (JHAs) were applied at the time of the peak in larval migration of E. leperii and when the second generation of A. mytilaspidis larvae were overwintering on E. leperii females.
First instar male larvae were more sensitive to JHA than female larvae. At a concentration of 0.1 a. i. % all the JHAs tested showed a similar efficacy (82–85 %) against E. leperii larvae.
The rate of parasitization was not affected by the lower concentrations of JHAs used, but at the high concentration they decreased parasitism. At a concentration of 0.5 a. i. %, hydroprene, methoprene and kinoprene disturbed the development of A. mytilaspidis. At a concentration of 0.1 a. i. % fenoxycarb and methoprene did not affect the percentage parasitism.
Zusammenfassung
Wirkungen der Juvenoide (JVH) Fenoxycarb, Hydropren, Kinopren und Methopren auf die Erstlarven der Schildlaus Epidiaspis leperii Sign. (Hom., Diaspididae) und ihres Ektoparasiten Aphytis mytilaspidis (Le Baron) (Hym., Aphelinidae)
Die vier genannten Juvenoide wurden gegen Epidiaspis leperii angewandt, als deren Erstlarven sich auf dem Höhepunkt ihrer Migration befanden, und als die Larven der zweiten Generation der Ektoparasiten an den Wirtsweibchen überwinterten.
Die männlichen Erstlarven erwiesen sich gegenüber den JVH empfindlicher als die weiblichen. Bei einer Konzentration von 0.1 % zeigten alle JVH eine ähnliche Wirkung (82–85 %) auf die E. leperii‐ Larven.
Die Parasitierungsrate wurde durch niedrige JVH‐Konzentrationen nicht beeinflußt, wohl aber durch höhere. Bei einer Konzentration von 0,5 % störten Hydropen, Methopren und Kinopren die Entwicklung von A. mytilaspidis. Bei 0,1 % beeinflußten Fenoxycarb und Methopren die Parasitierungsrate nicht.
The present investigation indicated that the citrus flower moth, Prays citri (Millière) showed that differences in their response to host plant species. However, P. citri population greatly preferred lime over navel orange and mandarin. Lime flowers received the highest numbers of P. citri throughout the whole period of investigation, while no infestation occurred on mandarin. Navel orange flowers were of intermediate rank for P. citri population. The obtained results illustrated that both larval and pupal populations exhibited one peak of seasonal abundance during 2015 and 2016 seasons. Distribution of P. citri population within host plants, based on the analysis of variance, was affected by directions. However, P. citri population was significantly higher at the south direction than the other cardinal directions (north, west and east) and center of the canopies. The present study showed that P. citri population exhibited positive response to the increase of mean temperature, while, it showed negative response to both relative humidity and wind speed. No significant differences were observed between the duration periods of all developmental stages which reared on different host (lime, navel orange and mandarin) flowers. Analysis of life table of P. citri population indicated that mortality of larval stage is the Key-stage mortality, which can induce population changes comparing to other specific stage mortalities.
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