About this product
You come down on a summer morning and the lawn looks like it has been dug over by hand. Turf flipped, holes scratched, soil scattered. That is not the chafer grub. That is the foxes, badgers, crows and magpies who have worked out there are chafer grubs underneath and spent the night getting at them. The grubs chew the grass roots from below, but the excavation that follows is usually the more distressing half of the problem.
Chafer larvae are the C-shaped white grubs of the garden chafer and cockchafer, feeding just below the surface through summer and autumn before pupating. The direct damage shows as yellow, sparse patches where the turf lifts away easily, because the roots have been eaten through. Treat the grubs and both problems go: nothing left to eat, and nothing left for the wildlife to dig for.
These are microscopic beneficial nematodes that target chafer larvae specifically. Watered into moist soil, they find the grubs and end the larval stage. Everything else is left alone: bees, butterflies, ladybirds, earthworms, birds, pets, children and your plants.
Timing decides whether this works, and the two windows are not equal. Late summer, roughly August to early October, is the one that matters. The grubs that hatched earlier in the year are still small and shallow, and the soil is warm and moist. Spring, April to May, is a fallback if you find damage before the larvae pupate, but the grubs are bigger and tougher by then and the result is noticeably poorer. If you are choosing between May and September, wait for September. Soil must be reliably above 12°C either way.
Water the lawn thoroughly the day before. Mix, apply evenly with the rose off the can or through a hose applicator, then water again straight away to wash the nematodes down to where the grubs are. Keep the lawn moist for one to two weeks afterwards, which is the part that most often gets skipped. Apply on an overcast day or in the evening, because strong direct sun is the one thing nematodes will not tolerate.
Expect this to work quietly rather than dramatically. Over the following weeks the wildlife stop digging and the patches stop spreading. Aerate in autumn, top-dress the damaged areas and overseed, and most lawns are back to themselves by the following spring. We pause supply in the cold months rather than sell you something that cannot work below 12°C.