Management of fungicidal resistance

Table VIII. Management of Fungicide Resistance in Practice... 

Management of Fungicide Resistance by Using Computer Simulation... 

Management of fungicide resistance requires some means of predicting the quantitative response of the target fungus population to various management alternatives. 

Figure 2. A strategy for management of fungicide-resistant Pen1cmiurn 1n harvested lemons.

The contribution FRAC Mode of Action Classification and Resistance Risk of Fungicides (Chapter 12), starting with a short introduction on the history of fungicides, explains the importance of individual modes of action relative to their market penetration, their mechanisms and occurrence of resistance, the importance and occurrence of practical resistance on the management of fungicide resistance by FRAC (Fungicide Resistance Action Committee) and its recommendations to farmers related to the modes of action of the different fungicides. 

General models of the selection of fungicide resistance have given us overall management strategies (2-8). However, the fungi... 

Table I. Dual Goals of Fungicide Resistance Management...

TABLE III. Evaluation of elements of Inherent and management risks of development of fungicide resistance (adapted, with permission, from ref. 23)... 

Action Items for the Implementation of Fungicide Resistance Research and Management Goals in North America... 

This is the first successful case of fungicide resistance management in Japan based on integrated collaboration of molecular biological and epidemiological approaches. 

Although we have accumulated a lot of experience since the practical problem of fungicide resistance first occurred in the early 1970 s, the recent outbreaks of resistance to Qols and MBI-Ds (melanin biosynthesis inhibitors, vAiich target scytalone dehydratase) demonstrated how resistance management is still difficult to achieve. 

Industry Involvement. Agrochemical companies did not escape being caught off guard by the relentless progression of resistance, nor was their response either coordinated or uniformly effective at first. In a candid assessment of the early days of resistance management, Delp wrote that "Industry s response to fungicide resistance problems varies from denial to active participation in the solution" (4 ). 

Table IV. Predicted relative effects of various management strategies on fungicide resistance and disease suppression using PhyCophthora infesCans Solanum tuberosum and protectant and systemic fungicides via simulation analysis Data are from Milgroom and Fry (1)...

Fitness. Fitness of the resistant isolates may be a potentially important factor in identifying strategies to manage fungicide resistance. If the resistant isolates are considerably less fit than sensitive ones, then reversion to sensitivity in a population becomes a realistic consideration. Unfortunately, if fitness of resistant types is very similar to that of sensitive types, there are few options. However, relative fitnesses of resistant and sensitive biotypes are rarely known, and knowledgeable application of model results awaits empirical evidence. 

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