Integrated Pest Management IPM Threshold of damage

One of the most complicated questions for management Integrated pest management is to define the Damage ThresholdWhen is the time to act?

Although complete knowledge of the field is impossible, it is possible to bring together all the information available to define management systems and methods. The key is to develop dynamic systems that can be modified as the field develops. This is why a damage threshold is determined.

In the case of turf, the response thresholds are determined not by direct economic losses as in agriculture, but by the aesthetics and playability of the surface.

The damage threshold benchmark for turfgrass is a tricky one to set, but it is the sweet spot between the appearance the user can tolerate and the expense to the property. How much damage can be expected? weed I tolerate on a street? o How many nematodes? or how many larvae? There are really few studies done defining where the limit is for the variables, so the experience of the maintenance team is vital for integrated pest management. They are the ones who must define when a pest can do serious damage to the turf. Gordon Witteveen, y Michael Bavier place great emphasis on their Practical guide for the management of grasses on golf courses, relating experience and daily observation with the appropriate management. Leaving behind the indiscriminate use of phytosanitary products. 

Ricardo Llorca Mata, Head Greenkeeper at Club de Golf Escorpión commented at the 40th annual Greenkeepers Congress that the use of monitoring tools such as POGO o TDR helped him to know the state of the turf. Not only because he knew the humidity or salinity of the soil. Frequent walks in the fields allowed him to know how the grass was developing and to detect signs of disease at a very early stage.

The balance is between economically profitable, sustainable in the long term, visually and playably acceptable.

Today, the use of high doses of fungicides should only have a curative use at times when the disease is advanced. It no longer makes sense to use such high doses when preventive passes are being made. And such preventive passes could be reduced if correlations between disease harassment and cultural work were studied. Often the damage is related to:

• Very low mowing
• Blades not sharp enough
• Highly humid areas
• Nutritional deficiencies.

In short, factors that are not conducive to having a strong, vigorous lawn that is not affected by disease.

Nowadays pest modelling is a reality that is not used as much as it should be. And its use is highly recommended as it alerts when all the ingredients are in place for a pest to explode. With this information, action can be much more specific, avoiding the use of broad-spectrum pesticides. One of the most important dangers is the lack of rotation between active ingredients in pesticides. The simplest organisms have many tools to develop resistance to active substances in the very short term.

Crop protection companies are striving to find products that help to regulate the microbiota and activate plant pest resistance mechanisms before pests appear.

To avoid such resistance, biotic regulation seems to be the way forward for the technology. This method tries to stimulate competition between beneficial and pathogenic micro-organisms. With the balance created, no one pest would stand out from another and the need for pesticides would be drastically reduced.

In addition to that, the occurrence of pests generates genetically induced resistance in many grass species. This acts as a kind of vaccine. Agronomist Hermes Aramendiz-Tatis, a professor at the University of Cordoba, explains how the Genetics of plant resistance and as the relationship between host (the pathogen) and host (the plant).

Plant genetics is aimed at stimulating both passive and active plant resistance mechanisms to pests.

Nor can we forget:

• The use of traps: Scent or food traps are excellent tools for controlling the population of many insects. They decimate their population without regenerating any resistance.

• Refugia: Refugia are untreated areas where the pathogen population can reproduce without the selection pressure of individuals resistant to the active substance being used. If refugia were used, only individuals resistant to the active substance would reproduce and the risk of resistance being passed on to offspring by propagation would be very high.

It is unrealistic to invest in a lawn that is not damaged by fungi, bacteria or insects. And it is logical that the more representative areas have lower thresholds than the less important areas.

As he asserts Peter Landschoot, Professor at Pennsylvania State University. Nor it is the same thing to tolerate grass rust that we know will not cause major damage as Pythium that can wreak havoc on the surface.