On the Timing and Application of Pesticides

Abstract

The model developed by J. C. Headley to illustrate the entomologists' concept of the economic threshold is presented and criticized. A two-variable model directed at the problems of optimal timing and pesticide application as well as optimal pest population level is presented. and h= a parameter relating the inverse of population units to dollar units of control costs.in dollars to pest density and time. The economic threshold is that population level where the marginal benefit from damage prevented by the control program is equal to the marginal cost of realizing that population through a control program. The model has four basic elements: a pest population growth function (equation 1.1), a pest damage function (equation 1.2), a product yield function (equation 1.3), and a pest control cost function (equation 1.4). Each of these elements is presented below.where P t = pest population level at time period t, the harvest time; P t-n = pest population level n periods prior to t; r= net growth rate of the pest population per time period; D, = cumulative damage at time period t, given as a function of P t, where the pest population has grown from P t-n to P, with no external interruption; A = a constant related to the pest damage tolerance level based on the recuperating potential of the crop; b= a parameter relating units of pest population to units of crop damage; Y = realized product yield at harvest time (t) in dollars; N = potential yield at harvest time if no pest damage, expressed in dollars; e= a parameter relating damage units to dollars; K = total cost in dollars of reducing the pest population to Pc.; at time t-n;r, = P t-n (1 + r)n

A dynamic bioeconomic analysis of mountain pine beetle epidemics

“…Similar to the problem of MPB control, the economic pest-management literature has focused on the optimal management of plant populations which sustain an economically damaging pest population (Hall and Norgaard 1973;Feder and Regev 1975). This research evaluates centralized and decentralized pesticide application intended to minimize losses in crop production.…”

Optimal control of locusts in subsistence farming areas

“…As a result, previously sprayed fields are not revisited by a swarm during a crop-growing season and, in turn, the number and timing of pesticide applications [cf. Hall and Norgaard (1973) and Saphores (2000)] and re-entry [cf. Lichtenberg, Spear and Zilberman (1993)] are not relevant issues in this locust-alley environment.…”

Economics and biological evolution

“…For example, studies of the cost of antibiotic resistance include Holmberg et al (1987) and Liss and Batchelor (1987) who point to the 'scarcity of analyses of this issue' (Holmberg et al 1987(Holmberg et al : 1065. Meanwhile, following earlier work by Hildebrandt (1960), Shoemaker (1973), and Hall and Norgaard (1973) on the optimal application of pesticides, Hueth and Regev (1974) and Regev et al (1983) pioneered the modelling of optimal use with increasing resistance -a move towards an evolutionary viewpoint. However, in their analysis resistance is irreversible, leading them to note that 'were we to relax this assumption the optimal pest-control policy might change drastically ' (p. 88).…”