Managing WFT with Mainspring

Mainspring aids in combating WFT resistance, enhancing IPM programmes with its unique, efficient, and sustainable pest control approach.

September 27, 2023
2 mins

With resistance build up a constant threat to workable IPM programmes to control WFT, Mainspring is an extremely welcome addition to the toolbox, says ICL technical manager – Sam Rivers.

One of the most serious pests in protected ornamentals, WFT pierce plant tissue cells and suck out the contents causing necrosis and mottling. Impacting the plant’s photosynthetic ability, this results in weaker plants while the wounding paves the way for secondary plant diseases, such as botrytis.

“Thanks to its translaminar effect, Mainspring targets WFT in hard-to-reach places, such as flowers and buds,” explains Sam. “With a very quick mode of action, once ingested the pest stop feeding fast.  This is key, as with a quick lifecycle WFT populations can literally explode.

“Based on the active ingredient cyantraniliprole, Mainspring has a unique mode of action and a different IRAC code to other chemical options available. It is bad practice to rely on two plant protection products with the same IRAC number, and therefore the same mode of action, as pests are more likely to develop resistance.

“The Sustainable Use Directive (SUD) is shaping the way we operate on the nursery – promoting a more sustainable approach to plant protection product usage. The SUD hierarchy of control begins with cultural controls, followed by biological, physical and lastly chemical.

Cultural control options for WFT include disposing of crop debris and neglected stock, removing weeds, use of clean equipment and avoiding taking cutting material from infested plants.

Biological options include predatory mites, beneficial nematodes and biopesticides. ICL’s Steinernema feltiae Seeka beneficial nematodes target WFT adults and larvae on the plant while contributing to pupae control in the growing media.  Seeka is recommended for use preventively and when pest pressure is low as nematodes have little impact on severe infestations. Physical control options, which immobilise the pest, are extremely limited for WFT.

The last line of control is chemical, which is where Mainspring plays its key role.  With a very fast  lifecycle, resistance build up to WFT can occur quickly through the misuse of chemicals.  These products should only be used when previous options have not delivered sufficient control, or if a WFT population has gone undetected and literally explodes overnight.

Mainspring controls the adult & larval stages of WFT and should be used when other options do not offer sufficient control. A maximum of 4 treatments (per annum) can be applied.

Based on spores of the soil-borne insect pathogenic fungus Metarhizum brunneum strain Ma43, Lalguard M52 has label approval for the control of vine weevil grubs and will also make a contribution to WFT control. This powerful new biopesticide performs best at temperatures between 15-30°C.


“Against a backdrop of changing industry culture, new laws such as the SUD and environmental ethics, biological products, such as Seeka (Steinernema feltiae) and Lalguard M52, offer practical benefits. As part of a planned IPM approach, these products are set to play an important role helping combat thrips on nurseries.

Mainspring, ICL has a IPM programme for controlling thrips in ornamental crops.