The team at Sherwood Chemicals has developed a unique termiticide foam that allows for application in tricky, hard to reach areas. 

With the arrival of non-repellent chemistries over recent years, the interest in using foams in termite control has grown significantly. Traditionally, pest managers have mixed their own foaming formulations. However, more recently, termite foams in aerosol formats have hit the market providing pest managers with an alternative option.

The concept of foaming with insecticides has been around for years. Foams are ideal formulations to deliver residual insecticide deposits to voids – areas where the application of liquids would be impractical or provide poor coverage. A well formulated foam will rapidly fill a void, delivering the insecticide to the required area. When the foam collapses and dries, it should leave an even distribution of the insecticide on the surface.

However, creating a high performing foam formulation is not always easy. If pest managers are going to mix their own foam formulations, they need to understand the properties of both the liquid termiticide they are using and the foaming agent they add. As such, it is important they undergo training with each product manufacturer to understand how to deliver the best results.

However, although this will help the pest manager to create a good foam, they are still ‘stuck’ with the liquid formulation they choose. These liquid formulations have been developed to deliver optimal performance as liquid soil treatments and may not have the ideal properties to deliver optimal performance as a foam. Two key attributes of liquid concentrates that effect foaming performance are surfactants and particle size.

The surfactants used in the different liquid concentrates will vary depending on the desired formulation properties and the cost target of the formulation – higher quality surfactants cost more. These surfactants are important in the dispersion and suspension of the active in the concentrate and in the diluted product.

A poor quality concentrate will start foam formulators at a disadvantage before they begin, as they are unlikely to get good active distribution. However, even with good concentrate formulations, their interaction with the foaming agent can also give rise to compatibility and active distribution issues.

Actives used in termite suspension concentrates are suspended particles. Good quality concentrates should have a particle size less than five microns and a narrow particle size range. To ensure good performance as a foam, these particles need to be evenly distributed within the foam and in most cases, the smaller the particle the better.

Ready-to-use termite foams – ‘foam in a can’ – provide precision and convenience when it comes to foaming. As they are pre-formulated, a quality product will have included the correct surfactant to deliver compatibility with the active and create the desired foam consistency. This will ensure even distribution of active within the product and therefore even distribution of the active after application.

Creating the foam itself is a combination of the foaming agent, pressure and nozzle design. DIY foam treatments rely on compressed air to create the pressure in the foaming equipment. An aerosol foam typically uses hydrocarbon propellants. The advantage of the aerosol format is that the pressure remains constant for the duration of each use and for the life-time of the can. With foaming equipment the pressure is changing all the time, creating variability in foam characteristics.

Certainly mixing your own foaming formulations can provide flexibility in creating foams of different characteristics – a ‘wet’ foam or a ‘dry’ foam. But for a foam specifically formulated for termite use, it is difficult to go past the convenience and precision of a ‘foam in a can’.

Ultraforce Termite Foam

Sherwood Chemicals have harnessed this knowledge and used fipronil to create Ultraforce termite foam. The formulation utilises the benefits of a dissolved fipronil formulation with quality surfactant/foaming agent and the consistency provided by hydrocarbon propellant.

One of the key challenges during development was to create the optimal foam characteristics. If the foam is too dry (like shaving foam), they found it remained in the foam state for too long, effectively blocking termites from entering the area and reducing performance. By creating a ‘wet’ foam that expands at a ratio of about 25:1, they established it returned to liquid state within six to eight minutes. By including an optimal amount of water it ensures the foam wets the surface and fipronil is deposited evenly (demonstrated in the main image above, with Ultraforce being applied by Dave Marless of Envirotechnics).

Ultraforce Termite foam was designed and developed specifically for the Australian market, with extensive trials being carried out around Australia. These trials established that a fipronil concentration of 0.6 g/kg delivered the best results with elimination times of between one to four weeks.

1-2 second spray bursts spread over the infested area gives the best results

Termite foam treatments with the Ultraforce aerosol are fast (no need for mixing), precise (easy to deliver 1-2 second bursts accurately) and there is no wastage (no need to mix excess product for a small job). Ultraforce foam is an ideal tool for spot or localised treatment of active termites in structures.

Ultraforce training dates will take place during November and December. Please contact John Ralph or Elton Ardene at Sherwood Chemicals or your local Globe Australia representative for more information.

Vorasith Kahasathien, former Managing Director, Sherwood Chemicals