Development of disease incidence of Entomophthoraceae in field populations of Plutella xylostella in the Philippines
1994
Riethmacher, G.W. (Deutsche Gesellschaft fuer Technische Zusammenarbeit (GTZ), Eschborn (Germany)) | Kranz, J.
Plutella xylostella (Diamondback moth, DBM) is being diseased on all brassicas grown in northern Luzon, Philippines, by Pandora blunckii and/or Zoophthora radicans with a disease incidence (DI) ranging from 1 to 97% (larvae) an 0 to 95% (pupae). The incidence mainly depends on the density of these stages (R2 = 0.87 and 0.92) and on the initial inoculum available in the fields. DI is always higher during drier periods, i.e., when brassicas are mainly grown, than in periods with rainfall. The disease progress curves correspond to the general concept of prey-predator-relationships with a time-lag of about 2 weeks, reaching peaks when the population densities of the DBM begin to decline. Some of the curves are bimodal. The infection rates r range from 0.07 to 0.77 per unit/day and the doubling time from 1.2 to 10.2 days. Some aspects in relation to the use of this information for the control of DBM are discussed
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