EFFICACY AND PERSISTENCE OF SOME NEMATICIDES IN CONTROLLING CITRUS NEMATODE

Abstract

the The aim efficiency of of present work was conducted to evaluate known and used nematicides for controlling citrus nematode , Tylenchulus semipenetrans, under field conditions . These nematicides included three organophosphorus and three carbamate , with different rates and formulations . The efficiency was based on soil sampling monthly throughout the whole growing season . Residues of one chemical from each group ( cadusafos and aldicarb ) in soil and citrus fruits were investigated . In addition evaluating susceptibility of some citrus rootstocks to citrus nematode was tested

The results could be summerized as follows : -

1- The results of extraction efficiency of citrus nematode , Tylenchulus semipenetrans for 30 days from untreated soil samples , varied from Sumnier to Winter Data analysis indicated that a significant differences for the first three days were found , while data for other intervals till 30 days were non s gnificant. Total extraction after four days reached 75.70 49.71 and 72.94% for untreated soil samples in summer and winter and aldicarb - treated soil , respectively .

2- Data analysis of the effect of 10 days storing period in the. refrigerator at 5 - 7 oc on the extraction efficiency of citrus nematode , T semipenetrans , was also differed from summer to winter and revealed significant differences from 9 and 10 days of storing in winter - collected samples . While summer- collected samples from 5 th to 10 th there were significant