Specific resistance loci in plants are generally very efficient in controlling development of pathogen populations. However, because of the strong selection pressure exerted, these resistances are often not durable. The probability of a resistance breakdown in a pathosystem depends on the evolutionary potential of the pathogen which is affected by: (i) the type of resistance (monogenic and/or polygenic), (ii) the type of reproduction of the pathogen (sexual and/or asexual), (iii) the capacity of the pathogen for dispersal, (iv) the resistance deployment strategy (pyramiding of specific resistances, mixture of cultivars, spatio-temporal alternation), (v) the size of the pathogen population, which is affected by control methods and environmental conditions. We propose the concept of Integrated Avirulence Management (IAM) to enhance the durability of specific resistances. IAM involves a strategy to limit the selection pressure exerted on pathogen populations and, at the same time, reduce the size of pathogen populations by combining cultural, physical, biological or chemical methods of control. Several breakdowns of resistance specific to Leptosphaeria maculans, the causal agent of phoma stem canker have occurred in Europe and in Australia. This review paper examines control methods to limit the size of L. maculans populations and discusses how this limitation of population size can enhance the durability of specific resistances. It proposes pathways for the development of a spatially explicit model to define IAM strategies. Simulation results are presented to demonstrate the potential uses of such a model for the oilseed rape/L. maculans pathosystem.

Improved resistance management for durable disease control : A case study of phoma stem canker of oilseed rape (Brassica napus)

The effects of sowing date and nitrogen availability during vegetative stages on Leptosphaeria maculans development on winter oilseed rape

Plant diseases are among the major constraints in the production of food crops and inflict significant losses to global agriculture. Pesticides are widely used to control plant diseases but their application is costly and, in some cases, may bring more disadvantages than benefits. Use of bioinoculants to control plant diseases is an economically viable and ecologically sustainable method of disease management. A large number of bioinoculants is available; among them, bioinoculant fungi constitute the majority and are widely used in different cropping systems. Important bioinoculants that directly parasitize plant pathogens include Trichoderma spp., Paecelomyces lilacinus, and Pochonia chlamydosporia. Plant growth-promoting fungi such as Aspergillus spp. and Penicillium spp. may also suppress plant pathogens. In general, bioinoculants are effective against seed- and soil-borne fungi and nematodes. However, an important limitation in their commercial use in crop protection is nonavailability of efficient immobilizing systems for delivery and survival of bioinoculants. This chapter describes important bioinoculants, their effects, and their mechanisms of action against plant diseases caused by fungi, bacteria, and nematodes. State-of-the-art technology available for the production of commercial formulation of bioinoculants, along with important lacuna, is also discussed.

Fungal Bioinoculants for Plant Disease Management

In field tests replicated in 2004 and 2005, 32 cultivars of spring barley were assessed for resistance to Fusarium head blight (FHB) by single floret inoculation and spray inoculation with Fusarium culmorum (W. G. Smith) Sacc. It was found that the weather conditions in individual years affect to a large extent the progression of FHB and production of mycotoxin deoxynivalenol (DON). At the same time, in both years the cultivars reacted to F. culmorum infection similarly with respect to areas under disease progress curve (AUDPC) values and content of mycotoxin DON. Spraying inoculation led to stronger infection. The biggest differences in AUDPC values were observed between the cultivars Brise and Celinka, and weak reaction was found in the cultivars Kompakt and Madonna. The cultivars Kompakt and Tolar were most resistant towards FHB. In both monitored years the variety Ludan contained the lowest amounts of mycotoxin DON. Cultivars with high infection and low DON content (r = 0.78) showed weak positive relationship between resistance to FBH and accumulation of DON (concentration 70–200 mg/kg). This is the first information on FHB and in vivo concentrations of DON in certificated barley cultivars in Slovakia.

https://link.springer.com/content/pdf/10.2478/s11756-007-0011-x.pdf

Response to Fusarium culmorum inoculation in barley

Influence of frequency and way of application of bio-preparate (Trichoderma asperellum) on limitation of potato late blight and yield of organic potato

The biopreparation Supresivit based on spores from the fungus Trichoderma harzianum was applied as a dressing mixed with mineral fertilizers: NPK, LAV (ammonium nitrate with limestone) and DASA (ammonium nitrate and ammonium sulphate). Our experimental plots with spring barley, winter wheat, winter oil rape, maize and potatoes were fertilized with the mixtures of the biopreparation (1 g, 0.5 g and 0.1 g per 1 kg of fertilizer). There were two check variants, the first variant without any fertilization and without biopreparation, the second with fertilizer and without biopreparation. We observed the infestation of plants with pathogenic fungi and yield parameters. In our experiments it was indicated that Trichoderma harzianum suppresses pathogenic fungi at the concentration 0,5 g of Supresivit per 1 kg of the fertilizer and higher ones. The plants from treated plots had lower infestation - decreasing about 5-15% superficial infestation: tan spot of barley - yellow leaf spot on cereals and leaf blotch of ba...

The Influence of the Application of Mineral Fertilizers with the Biopreparation Supresivit ( Trichoderma Harzianum ) on the Health and the Yield of Different Crops

Jan Hrubý

Papers

The Influence of the Application of Mineral Fertilizers with the Biopreparation Supresivit ( Trichoderma Harzianum ) on the Health and the Yield of Different Crops