How to estimate the efficacy of periodic control of an infectious plant disease

Certain infectious plant diseases are controlled by inspection and subsequent hand removal of diseased parts. In this paper we give two sets of criteria from which one can conclude whether this control effort is adequate or not. These criteria do not require knowledge of the infection- or detection rate of the disease but only use the structure of the contact matrix. Computer experiments give a feeling of how many inspections are needed in order to draw a conclusion.