Kermarrec, A.

Mauléon, H.

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LABORATORY  PRODUCTION O F  N E O A P L E C T A N A   C A R P O C A P S A E  
WEISER  AFFECTED BY NIPAGIN  AND  STREPTOMYCIN 
Alain KERMARREC and  Hervé MAULEON 
I N M ,  Centre  des Antilles, Station de  Zoologie e t  Lutte Biologique, 971 70 Petit  Bourg,  Guadeloupe. 
Biological control of insect pests by the rhabditid 
nematode Neoaelectana carpocapsae has shown a real 
potential for  agriculture  (Gaugler, 1981).  As far as 
tropical agriculture is concerned,  Laumond,  Mauléon & 
Kermarrec  (1979)  underlined  a large  host  range for this 
parasite in  Guadeloupe. Various studies also showed  a 
possible  control of the  banana weevil (Cosmopolites 
sordidus) by this worm, at least under experimentally 
controlled  conditions  (Kermarrec & Mauléon, 1974). 
Mass production of Neoaplectana  spp. should  no 
longer  present  any major technical  difficulty to industry. 
Nevertheless,  laboratory  rearings of small  quantities for 
experiments  still  necessitate  artificial  host  productions. 
We show here that  some ingredients used in artificial 
diets for  the  rearing of lepidopterous larvae may have 
tremendous effects on  the  production of the  nematodes, 
as already  underlined  by  Guennelon (1968) for  entomo- 
phagous insects. This seems particularly the case of 
antibiotics, like Nipagin  (methylparaben or methyl 
parahydroxybenzoate)  and  Streptomycin,  commonly 
used  to stabilise  diets. 
Material  and  methods 
Caterpillars of two Pyralid moths (Diatraea  saccharalis 
and Gallena rnellonella) are  used as follows : 
a) D.  saccharalis (second  and  third  instars)  are  reared 
on  fresh  sugarcane  and  on _an artificial  diet  contaiging 
1 %O Nipagin (&/J and composed of : agarose 5 g; 
semolina (corn) : 28 g; corn  spoutings 7 g;  beer  yeast 
7.5 g;  ascorbic  acid 1 g; benzoic  acid 0.25 g, Nipagin M 
0.2 g for  170 g of water. 
Some 250 caterpillars of the  sugarcane  borer  are 
opposed  to five  concentrations of infective larvae (L3) of 
N. carpocapsae : O, 20, 200, 2 000, and 20 O00 L 3 
" agriotos '' obtained  according  to  the  method  described 
by Dutky,  Hompson  and CantweII (1964). The contact 
is realised in 9 cm Petri dishes to evaluate LD 50 
variations (Bliss, 1935) according  to  hosts  diet. 
b) G. mellonella (second and third instars) are fed 
during four days on bee wax dipped  in  increasing 
concentrations of Nipagin M : 0,30 and 270 mg  Nipagin 
per 100 ml of water  some  ten  replicates of each  treat- 
ment  (n = 10 caterpillars  per treatment) are  placed  in 
Petri dishes,  each receiving 30 O00 L 3 of N. carpocapsae. 
Table 1 
Variation  of LD 50 of D. saccharalis larvae,  according to diet, 
three days after  infestation  by N. carpocapsae 
Diet  Sugarcane  Synthetic L D  50 
ratio 
LD 50 for al1 instars 300 63 O00 200 
LD 50  according 
to  instar .............. L 3 700  37 O00 50 
.............. L 5  50 12 O00 240 
Table 2 
Effect of Nipagin  and  Streptomycin  (ingestedlinjected) on the 
production of N. carpocapsae by G. mellonella caterpillars. 
The densities of produced nematodes are evaluated by a 
discrete  notatian  and  summed  (see  text) 
A. Nipagine Concentration 
(mg/100 ml water) 
(ingested 
by Galleria) O 30 270 
O/O parasitized 
Galleria 78  20 15 
Production 
of Neoaplectana 101 28  8 
B. Streptomycin Concentration  (ppm) 
(5 121 injected 
to Galleria) O 12  .50 100 
O/O parasitized 
Galleria 100 100 80 60 
Production 
of Neoaplectana 86  66  55 19 
C. Streptonzycin Streptomycin  Control 
(ingested 
by Galleria) 
Production 
of Neoaplectana 81  158 
Revue Nénlatol. 12 (1) : 103-104  (1989) 103 
c) G. mellonella caterpillars  are also submitted to 
Streptomycin : ingested  with wax or  injected (531  in a 
false  leg)  at different  concentrations (O, 12,50,100  ppm) 
and  placed  against 30 O00 L 3 of N. carpocapsae. 
The percentages of parasitized  caterpillars  are  evalua- 
ted after  eight days by  dissection and  the  production of 
N. carpocapsae (sexuates and new generation) is esti- 
mated  by  a  discrete  notation (O : none to 3 : very high 
density). The final  notation will be  the  sum of the  notes 
given to each  replication of the  treatment. 
Results 
Table 1 shows that  Nipagin clearly lowers suscepti- 
bility to N. carpocapsae by 200 times (al1 instars) and 
from 50 to 250 times  with larval aging  from  third  to  fifth 
instar. 
Table 2 (A, C )  underlines a dose linked effect for 
Nipagin  (ingested) and  Streptomycin (injected) on  the 
percentage of parasitized Gallena as well as on the 
production of new N. carpocapse. Higher  concentrations 
of Nipagin  occured  to  be  antiphagant to Galleria. 
Ingested  Streptomycin  answered  in  the  same  direction 
(Tab. 2, B) than  Nipagin by lowering  the  production of 
N. carpocapsae by  the insect  host. 
Conclusion 
The use of artificially  reared  caterpillars  to  produce 
infestive N. carpocapsae in  the  laboratory  must obviously 
take in account the fact that antimicrobial chernicals 
may  strongly  depress  hosts  suitability. This  observation 
is close to the  conclusions of Grenier (1  977)  on  entomo- 
phagous  insects. 
REFERENCES 
BLISS, C. 1. (1935). The calculation of the dosage-mortality 
curve. Ann. appl. Biol., 22 : 134-167. 
DUTKY, S. R., HOMPSON, J. V. & CANTWELL, G. E. (1964). A 
technique  for  mass  propagation of the DD-136  nematode. 
J. Ins. Pathol;, 6 : 417-422. 
GAUGLER, . (1981).  Biological  control  potential of neoaplec- 
tanid  nematodes. J. Nematol., 13 : 241-249. 
GRENIER, S. (1977). Effets nocifs de la Nipagine M sur le 
parasitoïde Ph y x e  caudata (Diptera : Tachinidae). Entomo- 
phaga, 22 : 230-236. 
GUENNELON, G. (1968). L’alimentation artificielle des larves 
de  lépidoptères  phytophages. Annls Epiphyt., 19 : 539-570. 
KERMARREC, A. & MAULEON, H. (1974). Synergie entre le 
Képone  et un ver  parasite  d’insectes  pour  détruire Cosmopo- 
lites sordidzrs, le charançon du bananier. Nouv. hlaraich. 
Vivr.  INM-Antilles-Guyane, 5 : 24-27. 
LAUMOND, C. MAULÉON, H. & KERMARREC, A. (1979). 
Données  nouvelles  sur  le  spectre  d’hôtes et le  parasitisme du 
nématode entomophage Neoaplectana carpocapsae. Ento- 
mophaga, 24 : 13-27. 
Accepté  pour publication le 24 mai 1988, 
Dates  de  publication  du volume 11 
Fascicule 1 (p. 1 à 118) ................ 24 février 1988 
Fascicule  4  (p.  371 à 474) ............ 16  novembre 1988 
Fascicule  2 (p. 119 à 266) ............ 10 mai 1988 
Fascicule 3 (p. 267 à 370 ............ 12  août 1988 
104 Revue Nérnatol. 12 (1) : 103-104 (1989) 


Laboratory production of Neoaplectana carpocapsae Weiser affected by nipagin and streptomycin

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