STRI
}
When turf managers heard that chlorpyrifos had been withdrawn from use in the amenity industry in 2016 STRI consultant, Emma Beggs, wasn’t sure we realised just what a significant problem leatherjackets would become for many. The problem Leatherjackets are the larvae of the cranefly, more commonly known as ‘daddy long-legs’. Damage caused by the grubs can range from no visible symptoms to complete sward destruction. Most turfgrass will harbour a low number of leatherjackets and show no adverse effects. The amount of damage is related to the number of leatherjackets present and 52 | Turf Matters | JANUARY-FEBRUARY 2021
the condition of the grass. Turfgrass that is already under stress will be more severely damaged by leatherjackets. Shallow-rooted grass plants find it more difficult to recover from attack. During the winter months, when turf is only growing slowly, leatherjackets may still be actively feeding. Slow spring turf recovery can be an indicator of what is happening beneath the surface. In addition, there can be significant damage caused by birds searching for the grubs, disrupting the turf surface with tufts of grass left loose and holes opened up in the sward. This results in very visible and obvious damage to the quality of turf playing surfaces and bird activity may be the first indication of an infestation.
The lifecycle Understanding the lifecycle is
important as it provides us with a chance to interrupt the growth and establishment of these grubs. The lifecycle differs depending on the species in question but there are two main species of cranefly that are considered pests. Tipula paludosa emerge as adults in August and September. Females don’t move far and mating occurs quickly with eggs being laid within 32 hours. Larvae enter a resting phase in the summer before pupation and emergence in late summer. Populations therefore tend to increase in specific areas. Tipula oleracea has two adult flight periods per year – one in August/ September and a second in May/June, although adults may also be present all summer. The females can lay more than one clutch of eggs resulting in