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Title: Alternatives to chemical control of the nematode Meloidogyne javanica in Tanzania
Author: Madulu, J. D.
Awarding Body: University of Aberdeen
Current Institution: University of Aberdeen
Date of Award: 1992
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The broad objectives were to better understand the biology of Meloidogyne javanica and to seek cultural and non-chemical control methods of controlling it in tobacco and vegetable rotations in Tanzania. In pot trials Tagetes erecta, Sesame orientale, Arachis hypogea and Zea mays were all shown to be non or poor hosts of M.javanica. These were tested as rotational crops in one or both of two field trials. The core of my work was two rotational trials which extended over three seasons. In the first and third seasons of the field trials susceptible crops (tobacco or tomato) were grown uniformly in all plots. In the second year the various rotational treatments were applied. In both trials Crotolaria ochroleuca greatly reduced M.javanica and increased yields in the third season. The role of root exudates in the effectiveness of T.erecta and C.ochroleuca was studied in pots. Exudate from T. erecta controlled M.javanica on tomato provided it was applied at or before juvenile invasion. That from C.ochroleuca had no effect. In the tomato trial a weedy fallow maintained a substantial population of M.javanica and its weed hosts were examined in a dry season survey of tobacco fields. Two thirds of these which were commonly found were hosts. Solarisation was tried as an additional means of controlling M.javanica. Water bath experiments suggested temperatures above 50oC were needed for rapid killing of M.javanica eggs. Such soil temperatures were not achieved even under polythene where the maximum was 45oC. Even so, eggs of M.javanica were killed over 2-3 weeks probably by a combination of temperature and drying. In other temperature studies the base temperature for development of M.javanica was found to be 12.8oC and thermal constant at 356oC days. In the continuous tomato plots in the field trial the incidence of M.javanica decreased in the third year associated with a high level of infection with the bacterial parasite Pasturia penetrans. In pot P.penetrans showed promise in reducing infection by M.javanica.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available