Extended Summaries: 9th Pesticide Chemistry Congress
TABLE 2
309
Insecticidal Activity of Substituted 2-Nitroiminoimidazolidines and Reference Compounds
Insecticidal activitya
Concentration
Pest
Stageb
(mg AI litre~1)
1
2a
2b
2c
5a
5b
5c
8a
8b
Spodoptera littoralis
Diabrotica balteata
Heliothis virescens
Aphis craccivora
Myzus persicae
Nilaparvata lugens
T etranychus urticae
L1
L3
L1
m.p.
m.p.
N3
100
100
100
100
12É5
100
100
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[
m.p.
a ]] [80% mortality; [ \30% mortality.
b L1: Ðrst-instar larvae, L3: third-instar larvae, m.p.: mixed population, N3: third-instar nymph.
D. balteata: Corn seedlings in a Petri dish were
treated with test solutions pipetted into the dish and
then infested with third-instar larvae. Samples were
checked six days after treatment for mortality and
growth regulation.
H. virescens: Eggs (0È24 h old) on Ðlter paper were
placed in Petri dishes on top of a layer of artiÐcial diet
and treated with test solutions introduced by pipette.
After six days incubation, samples were checked for egg
mortality, larval mortality and growth regulation.
A. craccivora: Pea seedlings, infested with a mixed
population were treated with test solutions in a spray
chamber. Samples were checked six days after treatment
for mortality (contact activity).
M. persicae: Pea seedlings, infested with a mixed
population were placed directly in the test solutions.
Samples were checked six days after introduction for
mortality (systemic activity).
N. lugens: Rice seedlings were treated in a spray
chamber with test solution, dried and infested with
third-instar nymphs. The samples were checked six to
the imidacloprid standard, so the study was discon-
tinued.
Acknowledgements
We wish to thank Dr P. MaienÐsch and Mr A. Rindlis-
bacher of Novartis Crop Protection for carrying out the
biological tests, and for helpful and stimulating dis-
cussions and suggestions.
References
1. Yamamoto, I., Agrochem. Jpn, 68 (1996) 14È5.
2
. Kagabu, S. & Matsuno, H., J. Agric. Food. Chem., 45,
(1997) 276È81.
3
. Tomlin, C. (ed.) T he Pesticide Manual, 11th edn. Crop Pro-
tection Publications, The Royal Society of Chemistry, 1994,
pp. 706È8.
4
5
6
. McKay, A. F. & Wright, G. F., J. Am. Chem. Soc., 70,
(1948) 430È1.
. Hassner, A. & Dehaen, W., J. Org. Chem., 56 (1991) 896È
900.
. Yamamoto, I., Tomizawa, M., Saito, T., Miyamoto, T.,
Walcott, E. C. & Sumikawa, K., Arch. Insect Biochem.
Physiol. 37 (1998) 24È32.
12 days after the treatment for mortality, growth regula-
tion and e†ects on F-1 generation.
T . urticae: Bean leaf discs on agar in Petri dishes
were infested with a mixed population, and, one day
later, were treated with test solution in a spray chamber.
Samples were checked for egg mortality, larval mortal-
ity, and adult mortality after 10 days incubation.
Structure Elucidation of Omphalotin, a Cyclic
Dodecapetide with Potent Nematicidal Activity
Isolated from Omphalotus olearius
3
Results and discussion
Edwin Bu
Heidrun Anke1 & Olov Sterner2*
chel,1 Anke Mayer,1 Ulrike Martini,1
Table 2 shows the results of insecticidal tests of some
new substituted 2-nitroiminoimidazolidines in compari-
son to imidacloprid (1). Compounds 2aÈc and 5aÈc,
were relatively inactive, in contrast to compounds 8aÈb
which were active at 100 mg AI litre~1 (contact) and
1
LB Biotechnology, University of Kaiserslautern,
D-67663 Kaiserslautern, Germany
Department of Organic Chemistry 2, Lund University, PO Box 124,
2
S-22100 Lund, Sweden
1
2É5 mg AI litre~1 (systemic). These results clearly
demonstrate that the 5-(2-chloropyridyl)methyl group is
necessary for biological activity. The mode of action of
Abstract: The structure and absolute conÐguration of ompha-
lotin, a cyclic dodecapeptide isolated from the basidiomycete
fungus Omphalotus olearius and possessing potent and selec-
tive activity against the plant pathogenic nematode Meloi-
dogyne incognita, was determined by a combination of
8
aÈb is probably similar to that of other neonicotinoid
insecticides.6 Further tests were carried out with these
compounds, but their activity was clearly poorer than