By Kabuba Purity

Integrated Pest Management (IPM) has since become a buzzword in the floriculture industry. It is the ideal concept to subscribe to and everyone aches to be seen either as an adopter or advocate of IPM. Nevertheless, beyond the hype, we have witnessed positive progress in the manner which Kenyan flower growers are implementing IPM measures in pest control programs.

However, it is still not exactly clear to some people what really constitutes Integrated Pest Management. The UN’s Food and Agriculture Organisation (FAO) defines Integrated Pest Management as the careful consideration of all available pest control techniques and subsequent integration of appropriate measures that discourage the development of pest populations and keep pesticides and other interventions to levels that are economically justified and reduce or minimize risks to human health and the environment. IPM emphasizes the growth of a healthy crop with the least possible disruption to agro-ecosystems and encourages natural pest control mechanisms.”

Integrated Pest Management

Use of sticky cards with Kairomone (thrips attractant) to trap adult thrips in a greenhouse

Benefits of Integrated Pest Management (IPM)

In a nutshell, IPM is about considering all the available options to combat target pests; followed by a conscious decision to prioritize the use of the options that are not only effective but pose the least harm to the environment and are also safe to humans. The core principles of IPM are outlined below:

  • The first key step is to define acceptable pest levels. The emphasis here is on control not eradication. The IPM programs set action thresholds and control measures are applied if those thresholds are exceeded.
  • The second step is to engage preventative cultural methods that minimize the risk of pest infestation and development. Such practices include selecting resistant varieties, crop sanitation, quarantine to restrict movement of infected materials etc.
  • Monitoring is the third crucial step. The grower should focus on inspection, identification and proper record keeping to understand target pest behaviour and reproductive cycles. The investment here is on qualified personnel, scouting programs and systems.
  • Mechanical control: This is physical removal of the target pest from the crop. Employ methods such as the hand-picking, barriers, traps and tillage to disrupt breeding.
  • Biological control: Use of natural organisms and materials such as beneficial insects (predatory mites, parasitic wasps) and beneficial microorganisms.
  • Responsible use of chemical pesticides: Chemical pesticides are employed as a last resort. They must also reach their intended target.

As you can see already, IPM is an intensive process and requires conscious effort from the grower. It calls for a deep understanding of insect pests and diseases, the various control methods available and judicious application of the same. While it might seem demanding in terms of time and resources, IPM poses numerous benefits to the grower that make the effort worth it in the long term.

These include: higher productivity, improved quality, reduced chemical residues, better chemical-resistance management, lower costs, and less harm to people and the environment. In this age of heightened market demands on sustainable production, growers who fully adopt IPM will find it very easy to comply with emerging demands and thus enjoy secure access to markets.

Biological control as the core tool in reducing pesticide use

As earlier highlighted, IPM will only manage to reduce pesticide use significantly only if the grower prioritizes the pest control methods in this sequential manner: mechanical control, biological control and judicious use of chemical pesticides. Given the limited options and practicability of mechanical methods, this leaves biological tools at centre stage.

In the Floricultural sector, there has been a gradual decline and rationalization in the use of chemical pesticides to control pests and diseases in favour of biological control. At the moment, we have some flower growers who are heavy users of biological agents to control a wide array of insect pests and diseases from the Red Spider Mite (RSM), Thrips, Nematodes, Mealy bugs, Caterpillars, Downy Mildew, Powdery Mildew, Botrytis, etc. To them, the benefits of bio-control agents are clear and they are always eager to try the next new product available to add to their arsenal.

Reduction tip 1: Target Key Pests First

Koppert Kenya (a key player in the biological Product Market) advises that in order for flower growers to able to make a significant reduction in pesticides use, they should first aim to use biological tools against their key problematic pests. This is because the bulk of chemical pesticides would be used to target the said pest.

In Roses this often translates to Red Spider Mite (RSM) and Thrips. One of the areas in which Koppert has mastered the deployment of effective and successful tools is in the control of the two spotted spider mite (Tetranychus urticae). Our unique approach involves the use of two predatory mites – Phytoseiulus persimilis (SPIDEX) and Amblyseius californicus (SPICAL).

The combined use of both predators prevents the occurrence of sudden upsurges of the spider mite. This is due to the inherent unique characteristics of SPICAL; a broader diet, resistance to high temperatures, low relative humidity & some pesticides. This means it can survive longer in the crop even in the absence of the pest, and thus is able to combat new infestations immediately they occur. Spical has also shown to reduce Thrips infestations by feeding on Thrips larvae. Interestingly, it has also been established that with consistent use of SPICAL growers use less Phytoseiulus in their RSM programs, thus reducing their costs.

Biological pest control

Amblyseius swirskii exhibits superior predation of thrips larvae

After successful implementation of spider mite control, growers need to watch out for Thrips, which are continually posing a threat to growers leading to the loss of valuable produce. Heavy Thrips infestation may occur at the most inconvenient time, such as close to the prime flower days when every cut-flower stem counts. However, this need not be the case because a comprehensive bio-control strategy that tackles the various stages of the pest’s life cycle can be employed.

Our strategy includes:

  • The use of the predatory mite Amblyseius swirskii (Swirski-Mite) which preys on the Thrips larvae, and
  • Intensive application of Horiver-TR (blue Horiver sticky cards)
  • Lurem-TR (Thrips attractant) for mass trapping of the Thrips adults

In future, we will also avail products to target the pupal stage such as Macro-Mite (Macrocheles robustulus), a soil dwelling predatory mite. Adding Attracker (a solution of selected sugars that lures Thrips) to ALL thripicides further increases the effectiveness of these insecticides when sprayed to control Thrips. Growers who have adopted this strategy have been able to reduce insecticides sprays by 25% to 75%. The predatory mite A. swirskii (Swirski-Mite) is also used for the control of Whitefly. It preys on the first larval instars of both the glasshouse whitefly and tobacco whitefly.

Reduction tip 2: Maintain healthy soil life

One of the greatest hurdles a grower has to overcome after a successful implementation of a bio-control program against the RSM and Thrips is the need for constant chemical intervention against fungal diseases especially Downey mildew, Powdery mildew and Botrytis.

In fact, recent information indicates that fungicides have the largest share in the current use of chemical pesticides. That is where the concept of healthy soil life comes in. The goal here is to eliminate the need for constant chemical intervention against fungal diseases especially Downey mildew which not only add to chemical load in a crop but also disrupt the bio-control programs which involve beneficial insects. At Koppert we are convinced that maximum disease suppression in the soil forms the key to a healthy and vigorous plant.

Soil health

Soil Health is an integral part of Integrated Pest Management

A well-balanced soil food web contributes to the health of plants. Plant roots communicate (signal) their environment by excreting exudates that feed the good microorganisms in the root. In return, the microorganisms avail to the plant nutrients, growth compounds and disease-suppressing compounds. The possibility of growing profitable crops using less fertiliser and pesticides can be a reality for every grower who is willing to start with this resilient cultivation. A healthy plant with good resistance levels is less susceptible to diseases such as Pythium, Fusarium, various Mildews and Botrytis. Ultimately, this guarantees operational security, greater yields of high quality, sustainable cultivation, and food safety.

The advances in the use of biological agents in IPM programs will continue to escalate in future. Increasingly, it is becoming more possible to grow healthy and profitable crops with minimal reliance to chemical pesticides. Kenyan flower growers can achieve great mileage if they embrace the above proposed tools of incorporating bio-control agents to target key pests and maintain a healthy soil-life

This article first appeared in the HortiNews magazine