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1 1 <br /> 1 <br /> Thresholds <br /> 1 <br /> 1 Recommendations for pest and vegetation control applications are <br /> often given in terms of calendar dates and/or intervals. (e.g.: "When foliage <br /> 1 appears, spray thoroughly every 4 days. When weather is warm and dry, <br /> 1 spray at 10 -day intervals. Repeat after rains." [ 9 ]) The need to treat <br /> susceptible vegetation is simply assumed. If a plant is vulnerable, it must <br /> 1 be "protected ". In integrated pest or vegetation management, this <br /> assumption of the need to treat is replaced by the concept of "thresholds ". <br /> Several different thresholds can be identified and are relevant at one <br /> 1 point or another in the management process. The damage threshold is the <br /> lowest pest population density at which damage occurs. The economic <br /> threshold, a fundamental IPM concept, is the point at which the density of <br /> 1 the pest requires a control measure (usually chemical) to prevent economic <br /> loss. DA] <br /> w will illustrate the concept The graph, below, t of these thresholds: p <br /> Treatment Applied <br /> ECONOMIC <br /> THRESHOLD <br /> DAMAGE <br /> THRESHOLD <br /> INFESTATION <br /> Elapsed Time 1 <br /> 11 <br />