Western Flower Thrips (Part 2)

Mainspring is based on the A.I cyantraniliprole and has a unique mode of action and contributes to an important part of managing resistance in your crop. Thanks to the translaminar effect, it is possible to fight pests in hard-to-reach places and fits into your integrated pest management system

Building Mainspring into an IPM plan requires an understanding of the legislation and how we approach issues on the nursery such a pest pressure.

The sustainable use directive which is under the sustainable use regulations is driving the way we operate on the nursery by promoting a more sustainable approach regarding the use of plant protection products. The directive is law throughout the UK and Europe and all growers are expected to follow the legislation which relate to promoting a safer more sustainable way of crop production across the industry.

Under the sustainable use directive, we have some guidance on how to raise and protect crops whilst also protecting the environment and this guidance is also known as the hierarchy of control. This begins with cultural control first followed by biological products, then physically acting products and lastly the use of chemical products which is where Mainspring will fall into.

Using Western flower Thrips as an example, we can go through how we would build an IPM plan to help control this pest on the nursery.

Under the sustainable use directive, we look at cultural control options first – cultural control referring to measures such as nursery hygiene, monitoring, climate control, irrigation etc. For Western flower thrips a few cultural control options would include practices such as disposing of crop debris, older neglected stock, removing weeds which can harbour this pest, using of clean equipment and not taking cutting material from infested plants. There’s quite a few strategies you can use but that hopefully gives a brief overview of some cultural options.

The next level in the hierarchy of control would be to look at biological options – there are various options available which can be used for western flower thrips such as – predatory mites, nematodes and biopesticides. You can achieve very high levels of control with this approach. Some of the issues with biological products is the application timing which must be accurate.

Some issues arise with compatibility too especially if you are using other biocontrol agents for other pests on the nursery so it’s crucial to speak to your suppliers to make sure you are maximising the efficacy of these options on the nursery. One product we have at ICL under the biological category is the beneficial nematode Steinernema feltiae which can be used to help control western flower thrip adults and larvae present on the plants but can also kill the pupal stages in the growing media. The consideration for using nematodes however is that they should be used preventively and should not be used if the infestation is severe which is also the case for many of the other biological options.

Next under the hierarchy of control is the use of physically acting products. For Western flower thrips there are not many options available under this category, so options are limited. Physically acting products work purely by physically immobilising the pest and do not enter the insect internally. So without the use of a physically acting product we go to the last line of control which is often the most controversial – Use of a chemical.

As I mentioned in part 1 the Western flower thrip lifecycle is very quick so resistance can occur quickly through the misuse of chemicals. The use of a chemical should only be necessary when the previous options have not sufficiently controlled the pest or if a pest population goes undetected and explodes overnight. Bear in mind that even a chemical cannot control the most severe outbreaks and sometimes it’s best to discard the crop and start again.

Mainspring has a very quick mode of action once ingested as it stops feeding – this is really useful when you consider western flower thrips have such a quick lifecycle as it can help prevent populations of this pest exploding if there has been an outbreak.

Another benefit if we hypothetically consider that the use of a chemical is necessary is that the IRAC code for Mainspring is different to other chemical options available. IRAC codes are given to insecticides and help develop rotations of chemicals that help reduce the risk of resistance occurring. IRAC standing for Insecticide Resistance Action Committee, and it is this committee who have developed a numerical coding system which help identify the different modes of action of chemicals e.g. if you are considering using two products which have the same IRAC number that means they have the same mode of action and therefore it is not advisable to use them together as resistance is likely to occur. The bigger the difference in the number the less likely resistance is to occur, and this should be considered when creating an IPM programme.

Mainspring belongs to the IRAC group 28 which is different to some of the other options available so can fit quite nicely into an IPM programme.

Overall Mainspring can be utilised as part of an IPM programme to help control western flower thrips. For more information, please contact your local technical area sales manager.