Demeure, Yves

Guiran, G. de

Horizon / Pleins textes

INFECTIVITY OF MELOIDOGYNE JAVANICA LARVAE 
FROM S O I L  . A T . p F  4.2 
- .  , 
OTAN's Tenth Annual Meeting -- 
University of Puer to  R i c o  
Hayaguez, h e r t o  Ri CO 
June 3-10, 1978 \\%. 
i 
'Laboratoire de  Nematologie, ORSTOM BP 1386, Dakar, Senegal. 
'Laboratoire de Faune du sol, INRA BP 1540, Dijon,  France. 
I &.,J [b  t 77, DEMEURE, Y., GUIRAN, G. (de).  2. 
I n f e c t i v i t y  of Meloidogyne j avan ica  l a r v a e  from s o i l  a t  pF 4.2 
Meloidogyne j avan ica  l a r v a e  from Senegal,  A f r i c a  less than 24 hours  
o l d  w e r e  ob ta ined  d i r e c t l y  from six-week-old egg masses and w e r e  exposed 
t o  t h e  following treatments: 
* 
1. 
silt 6.98%, c l a y  7.96%) and then d r i e d  u s i n g  t h e  d e  Guiran process  t o  
Half of t h e  larvae w e r e  p i p e t t e d  o n t o  sandy s o i l  (sand 85.06%, 
permanent w i l t i n g  p o i n t  (pF 4.2) and a moi s tu re  c o n t e n t  of 0.5%. 
2. The o t h e r  h a l f  of t h e  l a r v a e  w e r e  suspended in a phosphate 
b u f f e r  (pH 7.2) i n  a r a t i o  of 1:s H20. 
The l a r v a e  w e r e  s tored  under t h e s e  c o n d i t i o n s  f o r  1 4  and 2 8  days a t  
28O C. The c o n t r o l s  f o r  each ha rves t  d a t e  w e r e  f r e s h  l a r v a e  hatched from 
egg masses i n  a 24-hour period. A t  each h a r v e s t  d a t e ,  1 0  subsamples wi th  
25 a c t i v e  l a r v a e  obtained from Baermann f i ) ;~nel  e x t r a c t i o n  w e r e  inoculated 
on young tomato p l a n t s  c u l t i v a r  Roma (15 days o l d )  s u s c e p t i b l e  t o  
Meloidogyne javanica .  Af te r  f i v e  days i n  a g rov th  chamber a t  26" C ,  
t h e  tomato r o o t s  w e r e  s t a ined  with co t ton  b l u e  u s i n g  t h e  de Guiran process  
CO cuunz t h e  number of larvae t h a t  had e n t e r e d  each tomato p l a n t .  Tne 
mean p e n e t r a t i o n  w a s  17.4.1arvae f o r  t h e  c o n t r o l s ,  16.6, 16.0 f o r  t h e  
14- and 28-day s o i l  treatment and 8.6, 0.0 f o r  t h e  14- and 28-day b u f f e r  
t rea tment  s. 
S o i l  d r i e d  t o  t h e  permanent w i l t i n g  p o i n t  d i d  n o t  decrease  t h e  
i n f e c t i v i t y  of a c t i v e  - M. j avan ica  l a r v a e  f o r  a t  l eas t  28 days when 
compared w i t h , t h e  c o n t r o l s  and wi th  l a r v a e  s t o r e d  i n  a phosphate bu f fe r .  
P 
3.  
These d a t a  suggest  t h a t  g. j avan ica  l a r v a e  are capable  of undergoing 
quiescence i n  s o i l  and r e t a i n  i n f e c t i v i t y  f o r  a t  l e a s t  28 days. 
Laboratoire  d e  Nematologie ORSTOM BP 1386, Dakar, Senegal and Laboratoire  
de Faune du sol INRA BP 1540, Dijon, France. 
P 


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