Treating Turf pests in the spring

In mild winters turf pests such as Chafer grubs and Leatherjackets may not sink very low in the soil structure compared to harsh or average winters. This appears to be the case this winter in some parts of the United Kingdom. Dragonfli customers have reported Leatherjackets close and on the soil surface in the South West with some gardeners reporting huge populations. In other areas Chafer grubs were still close to the surface in December. This may mean they are not found very far down in the soil structure this year and could re-appear close to the surface to feed on grass roots much earlier than normal. If the mild winter is followed by a mild spring, this could speed up their life cycle. Traditionally nematode applications against Chafer grubs and Leatherjackets are carried out in the summer , when the next generation of larvae are present in the soil. This is for two reasons ; 1] the soil temperatures are higher, which provides better conditions for nematode activity and 2] the larvae are smaller and more easily penetrated by the nematodes. However when faced with overwintering populations of Chafer grubs or Leatherjacket larvae, the instinct to try and control this generation and prevent lawn damage can be overpowering! For this reason we are letting customers buy nematodes for spring treatments for the first time but are only supplying the more cold tolerant nematode; Steinernema feltiae, which is active from soil temperatures of about 8-10.c and upwards and will attack both Chafer grubs and Leatherjackets. If you can apply when the soil reaches these temperatures a percentage of the grubs and larvae can be killed but it will not be many compared to a summer application. For large populations, you will almost certainly need to treat the next generation in the summer. For Chafers this is normally from the end of July-October and for Leatherjackets from the end of August until October. Keep checking lawns in the summer for grub activity , as the sooner you can apply nematodes against the first small grubs, the better. The other very key factor to remember is moisture and water. Nematodes work much better in damp, moist conditions, so apply with lots of water and on dull days, as they are U.V sensitive. Try to keep lawns moist after application for at least 5-7 days. Nematodes provide a safe, natural solution against turf pests but you need to apply in the right conditions and be prepared to carry our regular treatments.

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