Why do spider mites explode in one greenhouse, while another grower with the same crop hardly sees any pressure? In many cases, the answer is not the pest itself. It is the interaction between climate, plant balance and crop susceptibility.
How do climate strategies influence plant health and pest pressure?
Plant Health starts with balance
A healthy plant is not simply a plant without pests or diseases. It is a plant that has enough energy to grow, produce and defend itself.
That energy comes from photosynthesis. When light, temperature, humidity and root activity are well balanced, the plant can convert this energy into sugars, proteins and other compounds that support both growth and natural resistance.
But when the plant is under pressure, for example during rapid growth, a heavy fruit load or sudden changes in weather, that balance can be disrupted. The plant then has fewer reserves available to cope with stress, making it more susceptible to pests and diseases.
Pests are often a symptom
This changes the way we look at pest management. Spider mites, thrips and aphids do not appear randomly. They are often responding to a crop that is already under stress.
Warm and dry conditions can increase leaf temperature and transpiration demand, while cool and humid conditions may reduce crop activity and increase disease pressure. In both cases, the climate affects not only the pest, but also the resilience of the plant itself.
This is why the most important question is not always, “How do I control this pest?”. A more useful question may be, “Why is my crop susceptible in the first place?”
The most critical moments are the transitions
Many problems arise during periods of change. A few sunny days after a dark period, a sudden drop in radiation or a shift in fruit load can quickly alter the balance between photosynthesis, water uptake and plant demand. These transition moments often determine whether the plant remains resilient or becomes vulnerable.
Growers who anticipate these periods and adjust their climate strategy proactively are usually better able to maintain stable plant health throughout the season.
Climate as your first line of defence
Climate control is often viewed as a tool to optimise production. But it is just as important for reducing pest and disease pressure. By keeping the plant in balance, you create a crop that is better equipped to cope with stress and less attractive to opportunistic pests and pathogens.
In that sense, climate strategy is not just about managing the environment around the plant. It is about strengthening the plant from within.
This article is part of the Plant Health Year Program, where leading consultants explore how climate, water, nutrition and plant physiology interact to determine plant health.
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