Porphyric Insecticides - Chlorophyll Biosynthesis and Technological Applications - page 412

Fig. 18.4 Response of T . ni larvae to the ingestion of two concentrations of ALA and variable
concentrations of Oph. Fourth instar larvae were placed for 17 h in darkness on diet containing 1 or
2 mMALA and O-Ph concentrations ranging from 0.05 to 0.2 mM. Every treatment was replicated
three times. At the end of dark-incubation a subsample of larvae were analyzed for tetrapyrrole
content while those remaining were placed in the light for observation of photodynamic damage.
The data was first analyzed as a factorial design with two levels of ALA and four levels of Oph.
Since the ALA Oph interaction was not significant, the data was reanalyzed separately for every
level of ALA, as a randomized complete block in order to generate LSD values for the two graphs
(Adapted from Gut et al. 1993 )
18.3.5 Concentrations of Dietary ALA
and 1,10-Phenanthroline Needed to Achieve
50 and 100 % Larval Kill in T. ni
Fifty percent larval kill in T . ni was achieved with diet containing as little as 1 mM
ALA and 0.1 mM Oph (Fig. 18.4 ). When the concentration of ALA and Oph were
raised to 2 and 0.2 mM respectively, 100 % mortality was achieved (Fig. 18.4 ).
Typical tetrapyrrole accumulation profiles that accompanied dark-treatments at
such low concentrations of ALA and Oph mixed with the diet are reported in
Table 18.9 . At these low concentrations of ALA and modulator, larval death
occurred after an extremely small amount of food consumption. The effective
concentrations of ALA and modulator given in Table 18.8 , are orders of magnitudes
lower than those previously reported (Rebeiz et al. 1988a ).