Archive for 2014

Role of IPM in reduction of pesticide residues in export beans

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French bean (Phaseolus vulgaris L.) is the most important horticultural crop in Kenya and accounts for over 60% of all exported vegetables. The main share of production is the small scale farmers who contribute more than 80% of production, and rely mainly on pesticides for pest management. French beans production involves high use of pesticides withm Many farmers reportedly applying up to 11 sprays per season, resulting in residue problems. This is partly fuelled by consumers in the developed countries, who form the bulk of the market for the French bean crop from developing countries, demanding for French beans with specific attributes such as size and spotlessness. This therefore, encourages farmers to rely increasingly on the use of pesticides to control pests. But the acceptable tolerance for pesticides residue in French beans is a major concern to the consumers. Among measures put in place in the importing countries are standards that require food products to meet prescribed maximum residue levels (MRLs) and another to reduce exposure of farm workers and other non-target fauna and flora. Emphasis is placed on consumer safety by use of approved less toxic pesticides and strict observance of the pre-harvest intervals which prescribes the latest date for pesticides use for ensuring safe residue levels.

In Kenya, there is growing evidence to show that alternative approaches and products are effective at managing pests without the side-effects associated with reliance on pesticides. Many farmers are successfully implementing Integrated Pest Management (IPM) on many different types of crops.

Dudutech has experience and proven track record in developing alternates to pesticides and in training and information on Good Agri-Practices (GAP) aimed at of giving farmers the skills, knowledge and confidence to make ecologically, socially and economically sound decisions on crop health. The alternatives such as traps, pheromones, and biocontrol products that play a role in IPM strategies are widely available. There is a wide range of Biological Control products (BCPs), that Dudutech is currently licensed to manufacture and distribute. The main products for French beans-IPM solutions are (Lecatech® (Lecanicilium lecani) for the control of whiteflies, thrips and aphids; Beauvitech® (Beauveria bassiana) for the control of thrips and whiteflies; Mytech® (Paecilomyces lilacanus) for the control of plant parasitic nematodes; Nematech H® (Heterorhabditis bacteriophora) for the control of cutworms, caterpillars and leafminer and Trichotech® (Trichoderma spp.) for the control of Fusarium, Pythium, Sclerotinia and Rhizoctonia).

What the industry desperately needs is an integrated approach to pest management. We need products which will replace pesticides. This ensures French beans do not exceed set MRLs. This approach has been adopted mainly by large scale producers who constitute over 20% of French beans production, while increasing farm income. Declaring IPM as the crop protection approach of choice is the way to go.

Biological pesticides are key to improving sustainability

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Finlays Horticulture, a supplier to M&S, are moving away from using synthetic pesticides, in response to increasing concerns over the effect they are having on the environment. With insects becoming more resistant to synthetic pesticides as well as the unknown effects that they may be having on farm workers and consumers, an alternative was needed.

In 2001 there were very few biological products available and Dudutech was started to develop biological products and create an integrated pest management strategy (IPM). Dudutech pioneered IPM in Kenya, finding and developing local strains of beneficial organisms, and innovative methods of application.

Taking the lead in this area, Dudutech has grown into an organisation employing more than 210 people, producing 17 products, and has successfully developed biological, physical and cultural methods to replace many traditional pesticide treatments.

Identifying that over 60% of insecticides used in flowers were to control the spidermite, Dudutech introduced a voracious predatory mite called Phytoseiulus persimilis to reduce the need for mite control pesticides. At Finlay Flowers South Africa, Phytoseiulus has reduced the level of synthetic pesticides used to combat spidermites to zero, and all 21 hectares of chrysanthemums are fully under this system. At present 90% of Finlays Horticulture’s farms only use biological methods to control spidermites and 100% of the area is under some form of IPM.

Recognising that a healthy soil grows a healthy plant, Dudutech has developed a wide range of beneficial soil organisms that are used on all Finlays Horticulture Farms. This has resulted in a further reduction in synthetic pesticide and fertilizer use, together with increasing soil biodiversity in line with the Finlays’ motto of long term sustainability.

A great example of ‘Environmentally Intelligent Farming’ in action!

The impetus of ‘hot spot treatment’ approach to bio-control in ornamentals

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The primary goal of bio-control is to optimize pest management in an economically sound, socially acceptable and environmentally friendly manner. Contrary to the initial perception that bio-control was optional and only applied to suppliers accessing certain direct markets in Europe, the past decade has seen a steady growth of bio-control across the Kenyan horticultural industry resulting in massive reduction in pesticide inputs. While stricter local and international regulation of pesticides have certainly played a part in this current state of affairs, greater flexibility and practicability of bio-control on the day to day farm operations are equally important.

Hot spot

IPM practitioners must continuously innovate and adopt specific techniques to judiciously manage pests in a sustainable way. One of the techniques gaining immense popularity is hot spot treatment. A hot spot is an unusual pressure point with relatively higher pest population in relation to homogeneity of its distribution on a crop. Hot spot treatment has been singled out as one of the viable methods of managing costs, reducing pesticide residues levels, countering secondary pests (e.g. mealybugs) outbreaks, managing resistance and ultimately producing quality flowers free of pests and diseases.

Dudutech pioneered this technique in partnership with DANIDA scientists in a study done in one of the Kenyan major horticultural farms. In the greenhouses where hot spot application of PHYTOTECH® (Phytosieulus persimilis) were done to target red spider mites, quicker control was achieved with fewer numbers of the bio-control agents (Phytosieulus spp) introduced compared to where blanket applications of the same were done. It was also noted that mortality due to sprays targeting other pests was minimal as the treated spots can be avoided. Another benefit observed was in the management of other pests especially mealybugs. Mealybugs share the same host niche as red spider mites in relation to crop canopy and have recently emerged as one of the most difficult pests to manage due to their complex physical characteristics. Growers have the option of spot spraying mealybug spots with their products of choice continuously without fear of suspending or affecting their bio-logical control programme unlike the blanket sprays.


On a number of field trials done in different flower growing regions in Kenya, the hot spot concept has successfully wiped out the issue of intermittent use of Phytoseiulus spp due to what is perceived as secondary pest infestation. Growers on massive hacterage have also gotten a reprieve due to the quantities applied per area treated against the actual projected blanket treatment. This has resulted into unusual demand for Biological control agents and eroded the element of cost. Another hidden benefit related to this concept is the opportunity to integrate other biological control agents with minimal cost and greater benefits. In conclusion, I can assure growers that with the adoption of the hot spot approach, one can effectively achieve satisfactory pest control saving up to 40-60% of their IPM budget. Patience, commitment, trust, precise scouting and the will to invest remain the key pillars of a successful IPM programme.