As in case of 5% solution, the time span of 1st, 2nd, 3rd, 4th, 5th, and 6th instar
increased a little than the time taken by the larva fed on the leaves treated with 2% neem solution.
Duration of the second instar
was shorter than in the other ones, and Sa was the longest (Table 1).
Their eggs were removed daily and kept in Petri dishes (diameter = 8.5 cm) with the bottoms covered with filter paper moistened with distilled water, until they reached the second instar
. The nymphs were then transferred to breeding cages (17.7 x 26.2 x 14.7 cm) because they begin to predate in this stage.
In this study, the duration of instars
2-5 was considerably shorter than reported by Matthiesen (1971) (148 days, n = 5; 281 days, n = 4; 362 days, n = 2 and 520 days, n= 1) for the same species.
Approaching any saltbush elicited an explosive, popcorn-like spectacle as adults and various instars
reacted to shadows or movement, launching toward cover in the center of the bush, a behavior reported by Wallace (1955) and Barnum (1964).
The [LT.sub.50] values of the four compounds tested after 24 h on 2nd instar
larvae were 9.2, 6.4, 1.1 and 1.8 day for Dursban, SpinTor, Ecotech Bio, and Neemix, respectively (Table 1).
In the summer nymphs of Santa Fe, 31.25% of individuals were males and 68.75% females; males had five instars
, while females went through five or six instars
(54.54% and 45.45%, respectively).
's duration was between two and four days for immature larvae and six or seven days for last instar
larvae (Table 1).
The material studied included 48 first instar
larvae and 127 second instar
However, there were some inconsistencies in the application of descriptive information attributed to the first instar
Recorded data analysis showed that larval weight of silkworm in 1st, 2nd and 3rd days of 5th instar
did not increased in two groups significantly while it increased in 7th day of last instar
significantly in silkworm larvae fed on Kokosa variety (P<0.05).
The Generalized Linear Model with a Gamma error distribution was applied for statistical comparison of larval length and head capsule width between species in each instar
. Survival of larvae was recorded by counting living individuals at each larval instar
of development until the first pupa was observed.