Neem Azal-T/S, Neudosan and Spruzit flu¨ssig at different concentrations were evaluated against the second and fourth instar larvae of E. chrysomelina under laboratory conditions. In case of acute effects, the highest mortality was recorded when larvae were offered squash leaves treated with the highest concentration (2%) of Neem Azal-T/S, and the lowest mortality was, however recorded after treating them with the lowest concentration (0.25%). On the other hand, the second instar larvae were more susceptible to any compound at any concentration than the fourth instar one. One per cent Neudosan formulation showed the highest toxicity to both the 2nd and 4th instar larvae. As the concentration of this compound decreased the mortality percentage of treated larvae decreased to reach the minimum at the lowest concentration (0.25%). The same trend could be applied for Spruzit flu¨ssig compound. When Neem Azal-T/S was compared with Neudosan, the later at any concentration was more toxic than the former. Generally, Neudosan and Spruzit flu¨ssig seemed to be active against E. chrysomelina during the first three days after treatment, then, deterioration occurred among this compound. In case of latent effects, the duration of the treated fourth instar larvae of E. chrysomelina with any tested compound, was prolonged. An increase in the concentration caused prolongation of this period to reach the longest at the highest concentration. This prolongation, was more pronounced after Neem Azal-T/S treatment followed by Neudosan and Spruzit flu¨ssig. The same trend could be applied for the duration of the pupal stage as being affected by the different concentrations of the tested compounds which were applied to the fourth instar larvae. However, adults of E. Chrysomelina treated as fourth instar larvae with high concentrations of Neem Azal-T/S showed some adult malformations. The sex ratios of adults produced from fourth instar larvae treated with different concentrations of the tested natural compounds were about 1 : 1, except for two cases; 1% Neudosan where the number of females were double the number of males and 0.5% Spruzit flu¨ssig where the number of males were double the number of females. An increase in the concentration of any tested compound caused an obvious decrease in the percentage of emerged adults. The least emergence percentage was recorded in the case of Spruzit flu¨ssig, followed by Neudosan and Neem Azal-T/S. Treating the fourth instar larvae with the different concentrations of the tested natural compounds significantly shortened the longevity of produced adults and decreased the fecundity.
The number of progeny of Bracon brevicornis was greatly affected by the number of deposited eggs of Bracon females per host larva. The increase in the egg clutch size from 5 to 25 eggs/larva increases the progeny production. On the other hand, the increase in the egg clutch size of the parasitoid decreases the body size of produced female progeny. The ratios of parasitoid females‐host larvae and time of parasitization which leads to optimal parasitism were studied. The most appropriate crowding level of B. brevicornis females to O. nubilalis full grown larvae was studied. The sex ratio of produced parasitoid progeny was significantly affected by changing the sex ratio of parent parasitoids, while there was no effect on the number of deposited eggs per host.
The effect of different constant temperatures (20, 23, 25 and 30' C) combined with 70 O/o R.H. on the weights of different larval instars, prepupae, cocoons, pupae and cocoon cortex of the Eri silkworm, Attacus ricini (Boisd.) was studied.All of these biological aspects were much affected by temperature. The increase in temperature decreased the weight of larvae, pupae and cocoon cortex. The most suitable temperature for producing the silk in a highly quantity was observed when the rearing temperature was 2 0 ' C.
A . A . G o m a aZusammenfassung Zur Wirkung der Temperatur auf die Seidenproduktion von Attacus ricini Boisd. (Lepid. -Saturinidae) Es wurde der Einflufi konstanter Temperaturen (20, 23, 25 und 30' C), kombiniert mit 7Oo/o LF auf das Gewicht der Larvenstadien, der Vorpuppen, Kokonpuppen und des Kokonmantels von A. ricini untersucht. Alle Stadien sowie der Kokonmantel wurden stark von der Temperatur beeinflufit. Zunehmende Warme bewirkte eine Abnahme des Larven-und Puppengewichts sowie des Kokonmantels. Die hochste Seidenproduktion wurde bei Aufzuchten der Larven um 20' C erzielt.
AbstractFuryltriazine applied on the day of pupation affected oogenesis. Degeneration at various levels may appear after low doses, but ovaries later recover. Furyltriazine applied on the 4th day had the same morphological effects, only stronger, and recovery was very rare. The hatchability of eggs was lower and larvae died mostly before or after hatching, and the rest before pupation. Furyltriazine prolongs adult life and also affects other functions of the body; details will be given in a separate paper. Furyltriazine is a promising chernosterilant of Trogoderma granarium. Z . ang. Enr. 74 (1973). 274-281 @ 1973 Verlafi Paul ['arc!, Hamburg u n d Berlin ASTLl-Coden: Z.4NI.AI-
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