Role of Micronutrients in Crop Disease Suppression

Plant diseases continue to play a major limiting role in agricultural production. The control of plant diseases using pesticides, and the rising cost of production, continues to raise concerns and have dictated the need for improved crop management practices.

Crop nutrients can affect disease tolerance or resistance of plants to pathogens.

IPM MasterClass 2011 guests will recall the powerful presentation by Prof. Don Huber. As Dr. Huber states “It is clear that the severity of most diseases can be reduced and the chemical, biological, or genetic control of many plant pathogens enhanced by proper nutrition”.

Following Dr Huber’s  IPM MasterClass 2011, Dr. Ismail Cakmak, in 2012,  reiterated and expanded the discussion around nutrients, particularly micronutrients, in plant health.

“Irrespective of approaches applied in disease control, mineral nutritional status of plants substantially affects plant resistance and tolerance and must be considered in all types of disease management systems”.

“Increasing evidence is available showing that mineral nutrient deficiency or imbalance in mineral nutrition supply ( eg., excess of N and low supply K and micronutrients), greatly increases susceptibility of crop plants to pathogen attack”.

“Mineral nutrition status of plants is very often ignored or unrecognised in practical agriculture and even in breeding programs, this is especially true for micronutrients”.

Soil and crop nutrition have always been a primary component of disease control. Supporting the growth of a healthy plant through grower practice is a key aim to reduce plant stress.

On the most basic level, plants suffering nutrient stress will be less vigorous and more susceptible to a variety of diseases. In this respect, all nutrients affect plant disease. However, some nutrient elements have a direct and greater impact on plant diseases than others.

“Zinc and Boron: most important micronutrients affecting membrane stability”. Cakmak IPM MasterClass 2012

Zn deficient wheat   Source: www.cropwatch.unl.edu 5/4/2014

Disease resistance in plants is primarily a function of genetics. However, the ability of a plant to express its genetic potential can be affected by mineral nutrition.

Soil and Plant Analysis – managing your crop.

The conNEXUS global  Soil and Crop Agronomy Service promotes a range of soil and plant analysis to assist in determining the nutrient status of the soil and crops. Growers often ask when should I sample?, to which we reply now and often. We encourage growers to sample both soil and plants to build a sound understanding of what is happening in the soil and the plant. Modelling nutrient use in the plant and nutrient removal and harvest are simple measures to continually improve nutrient and plant management. Using small trial plots to remeasure results is a simple way to determine the level of change and improvements.

Fertilizer recommendations are developed to optimize nutrient uptake and provide the crop with adequate nutrients for normal growth and yield. In most situations, this level of nutrients will also be sufficient to enable the crop to maximize disease resistance. This said, nutrient and disease interaction remain complex.

IPM MasterClass 2014 – P SCHOOL, 26^th June, Alan Heard Pavilion, Wimmera Event Centre, Horsham.

Registration and Enquiry:
Owen McCarron 0419 006 100
Darren Cribbes 0400 600 556

Bibliography:

Graham and Webb 1991, SSSA PublicationsHuber and Graham  1999 , Howarth PressHuber 2011 pers. comm.Cakmak 2012 pers. Comm.A-Fahdawi MS, Able J, Evans M,  Able AJ, 2014, Response of durum wheat to different levels of zinc and Fusarium pseudograminearum, CSIRO Publishing Crop & Pasture Science.