Beneficial nematode for biocontrol of pests

 

Chlorpyrifos (also known by the trademark Dursban, Equity) and Imidacloprid (Merit Turf) have been outlawed by the EU over concerns of harmful effects on the human nervous system and honey bees when sprayed in the air or through consumption of crops which have been treated with them. Fortunately, new products using beneficial insect-parasitic nematodes (roundworms), which are completely harmless to humans and the environment, as natural biocontrol agents can be a very effective replacement and in many cases showing increased kill rates over ‘traditional’ pesticides.

 

Entomopathogenic parasitic nematodes (EPN’s) have been commercialised over recent decades to control various insect pests currently affecting the agricultural, horticultural and forestry industries. Soil moisture is one of the most important factors influencing the survival, persistence and efficacy of nematodes in the field. It also appears that water repellency or hydrophobicity is becoming a wider problem in the soil, making it more difficult for the nematodes to reach their prey. Various commercial products have been developed over many years to improve the negative effects of soil water repellency. In general, soil surfactants, wetting agents or soil penetrants lower the interfacial tension between a hydrophilic and non-wettable hydrophobic stage. These surfactants work to improve the way water moves across the soil profile and increase water efficiency by managing water repellency and homogenous distribution. The use of such products in conjunction with specific nematode species targeted to control specific pests is an area in which Dr Minshad A Ansari has been cretinously developing. 

 

 

"We believe the current gap in the market can be filled with the use of nematodes," said Dr Ansari, Chief Executive of Bionema.  "Biological control is the future and many more products are on the way. Natural pest control makes even more sense now for commercial growers, greenkeepers and foresters.

 

"As we have seen, chemical control is becoming less and less effective as insect resistance has increased and options are narrowing due to the reduction of traditional chemical pesticides available on the market."

 

Bionema has developed the NemaTrdent® strategy for biological pest control. NemaTrident is a unique three component Integrated Pest Management (IPM) solution which provides maximum dispersal into soil or growing media where the tiny worms increase pest control throughout an extended growing season.  The NemaTrident® range comprises different species of naturally occurring, beneficial nematodes within the Heterorhabditis and Steinernema genera.  The three components comprising the NemaTrident® solution are (i) infective juveniles of nematode (ii) approved soil conditioner (TRANSFORMER) (iii) built in consultancy, support and training package to maximise efficacy and successful application. 

 

The unique NemaTrident® three component solution ensures maximum dispersal of nematodes when applied with the tested and approved soil conditioner which improves the water holding capacity of soil and or growing media so that the nematodes can get to work and do their job, said Dr Ansari. 

 

 

To facilitate the dispersal and movement of nematodes within soil or growing media, we apply them in conjunction with approved soil conditioner. In the golf course, sports turf and amenity sectors, the nematodes are applied in two ways, 1st using a unique soil injection system (where available) or hollow core tine equipment and 2nd using a vehicle mounted boom sprayer. Drip irrigation is frequently used in soft fruit and overhead in ornamentals. Timing is also a critical factor to successful application along with an in-depth understanding of the targeted pest behavior and lifecycle. The most susceptible stages of the targeted insects are either early instar or pupae, whilst these are within the soil. This is when the insects are at their most vulnerable to attack from nematodes, providing there is suitable moisture in in the soil to establish nematode population and temperatures are at an optimum level.

 

When applied using a vehicle mounted boom sprayer directly on to the leaves of the grass, it is critically important to irrigate the intended area sufficiently before treatment and to keep the treated area moist for at least 3-6 hours per day for two weeks after application.  This allows sufficient time for the nematode to seek out and kill the larvae and a new generation of nematode to be reproduced inside. Once the nematodes have killed the insect, approximately 80-100 thousand new infective juveniles emerge from the dead larva and go in search of other larvae, says Dr Ansari.  

 

 

With all the benefits of three-component solution – safe to use, no harmful residues or side effects – the products specifically developed for the turf and amenity industry are NemaTrident® C and NemaTrident® L. These products have been specially developed to aid green keepers and pitch managers in their fight against soil dwelling insects to protect golf greens, football pitches, rugby grounds and all sports and amenity turf.

 

The most common pests within the sports turf and amenity industry are chafers, crane flies and cutworms. Damage to sports and amenity turf grass by these pests is a major problem, not only due to the severe damage to plant roots caused by the feeding larvae but also the foraging wildlife such as birds foxes and badgers etc which destroy the surface in search of the protein rich grubs. All these pests can be controlled using nematodes. NemaTrident® C can be used against chafer grubs such as Welsh chafer (Hoplia philanthus), garden chafer (Phyllopertha horticola), summer chafer (Amphimallon solstitialis), May beetle (Melolontha melolontha) and brown chafer (Serica brunnea), and NemaTrident® L against larvae (leatherjackets) of crane fly (Tipula spp), mole crickets (Gryllotalpa gryllotapla) and cutworms (Agrotis spp). It is critical that the pest is correctly identified before application so that Bionema can tailor the IPM program accordingly. This can be quickly done onsite or by sending samples in to Bionema for accurate identification. Reducing chafers population levels can quickly and dramatically improve turf quality and performance.

 

 

Black vine weevil, Otiorhynchus sulcatus is a major pest of horticultural crops and is the cause of an estimated £40 million crop damages and losses to the UK and more than £2 billion in EU horticultural industry annually. The larval stage of vine weevil causes severe damage to many plant species by feeding on plant roots, rhizomes and the bases of woody stems. Larvae can girdle the root crown, and strip bark from woody stems and even large plants can die within a brief period. More than 200 species of crop plants and ornamentals are known to be particularly susceptible to vine weevil attack, including strawberry, raspberry, blackcurrant, blueberry, grapevine, yew, rhododendron, azalea, euonymus, camellia, cyclamen, rose, geranium, and primula. All are very valuable crops.

 

Field trials were conducted in the UK and EU by Bionema, using NemaTrident®H to control vine weevil in strawberry plantations and ornamental nurseries, showed that using nematode products delivered 20-30% higher control than other products in the market – delivering up to 95% kill rate for vine weevil at temperatures as low as 8°C. 

 

"Using the unique solution provided by our three component product ensures maximum dispersal and penetration into the soil and growing media by the infective juvenile nematodes, which then hunt out larvae and kill them quickly. The NemaTrident system and methodology is also proving effective in controlling pupae of Western Flower Thrips in strawberry and Chrysanthemum, which has become resistant to currently used insecticides," said Dr Ansari.

 

Dr Ansari also added that the compatibility of the unique soil transformer formulation and the nematode was critical to the enhanced efficacy of its system.  The nematodes viability was not affected after 3 and 6 hours tank mix unlike other wetting agents and chemicals where nematode viability was inhibited. Furthermore, the health and wellbeing of the workers in charge of pest control is not compromised due to the omission of potentially harmful chemicals.  

 

Bionema believe that the NemaTrident IPM program utilising all their key components combined with customized training, support and advice is the only way of ensuring successful results and ensuring the further development of biological pest control products. 

 

Bionema have launched seven new nematode products for professional growers, green keepers and foresters for various insect pest control. 

 

 

Nematodes actively search for insect larvae within soil and growing media following CO2 trails left by the feeding host insect. They enter the insect via natural openings and then release symbiotic bacteria.  These bacteria then infect and kill the insect within 24-48 hours, depending on host species and then produce further infective juveniles which exit the dead host and go in search of other insects to infect. The Infective juvenile stage is the only stage at which the nematodes can live while outside the body of an insect. 

 

The Bionema Quality Assurance service is the EU’s only third-party assessment for biopesticide products, ensuring the highest quality for farmers and growers delivered by industry experts.

 

 

- Nematodes are susceptible to ultra-violet light and desiccation. Apply during early morning or late evening. Avoid application in bright sunlight.

- Apply when you expect the soil or growing media temperature to be over 12°C for at least 3 - 6 hours per day.

- The entire two pack mixture should be used together.

- Do not use a filter in the nozzle to avoid blockages.

- Avoid excessive irrigation just after treatment

 

 

The Bionema Specialist training package is designed for Professional Growers, Greenkeepers and Foresters to help maximise the efficacy of biological integrated pest control programs by providing all the necessary information needed to ensure success.

 

These include practical demonstrations, laboratory and field-based work, providing understanding of:

 

- Overview of entomopathogenic nematodes as biopesticides

- Isolation and identification of entomopathogenic nematodes.

- Mass production of entomopathogenic nematodes.

- Behaviour, population ecology, competition, survival and compatibility

- Quality assessment.

- Identification of target insect pest species.

- Product label and interpretation including handling, storage, and transportation.

- Application of entomopathogenic nematodes against major crops and pests in agriculture, horticulture and turf and amenity.

- Integration of entomopathogenic nematodes with other crop protection techniques.

 

“There is no room for error” says Dr Ansari. “It is important to ensure sufficient moisture content and to monitor soil temperature amongst other things for the nematodes to work effectively.  It is essential to ensure the nematodes are delivered to the target pest as quickly as possible, and because nematodes cannot be seen with the naked eye, it is important to check their activity with a microscope. We always recommend that spot samples are taken and inspected before spraying to check nematode activity. There would be little point in applying inactive nematodes to target known pest infestations.

 

And there are new developments in the pipeline for the future, according to Dr Ansari.  Bionema is to increase its investment in the development of new formulations and biopesticide products for crop pest control.  “There are groundbreaking products from Bionema already in advanced stages of development and we are also investigating better delivery mechanisms to improve efficacy, “he said.

 

"There is a real need for these natural alternatives which are becoming even more effective as we look to the future where there is likely to be reduced rainfall, where traditional methods have begun to fail and as there are more people to feed," said Dr Ansari. "By increasing productivity - up to 50% of the crops in the US can be lost to pests - we at Bionema plan to make real difference to the future of the planet, by helping farmers and growers save money, and reduce yield losses due to pest infestations".

More Articles from AgroPages' latest magazine - 2017 Biopesticide Supplement