Leatherjackets, also known as Daddy Long Legs, are the larvae of the Crane Fly. Crane Flies are an insect within the Tipulidae family. There are approximately 15,000 different species of Crane Fly worldwide, existing in many different habitats some of which are completely aquatic. The lifespan of the adult is commonly only ten to fifteen days though the annual hatch may go on for a month. The sole purpose of the brief adult stage is to mate, the flies then die, and the majority of the lifecycle of a Crane Fly is spent as a Leatherjacket. They periodically come to the attention of people in September flying ungracefully around exterior lights and invading households in search of a mate.
The Crane Fly comes to the attention of the turf manager in its Leatherjacket larval stage. There are two species of Crane Fly in the UK that damage turf, Tipula paludosa and T. oleracea. The Leatherjackets feed on the roots of the grass plant making the plant more susceptible to disease and killing the plant. Major damage to the turf can be done by predators that are after an easy and abundant meal, starlings and other birds can congregate in vast numbers and decimate surfaces in a very short period of time. Climatic factors play a larger role in population control than the presence of predators. Damage to turf can be seen from September through the autumn, winter and into the spring.
The first indication of a problem is usually birds pecking and damaging the surface, in severe infestations the turf turns yellow in patches and bare areas start to appear. Lift back the turf to find Leatherjackets feeding on the roots of the grass plant; they generally feed at the edge of an infected area. The larvae are a typical grub shape: an elongated grey/brown tubular body without any legs, up to 30mm long. The adults look similar to very large mosquito"s although they have a very distinct ungainly flight unlike a mosquito"s flight. Their bodies are long and thin, so much so, that it is very easy to break off their legs when trying to catch them. Adult Crane Flies do not damage turf, nor do they bite or sting.
Attention to the problem is generally brought about by predators although preventative measures as well as curative action can be adopted to help prevent Leatherjackets damaging areas of turf. Control of Leatherjackets is relatively easy using broad-spectrum insecticides but distinguishing which areas require applications in advance of the damage remains the major problem.
Nemasys Leatherjacket Killer utilises the natural predator of leatherjackets in massively large numbers to eradicate the problem. These can be applied as soon as the problem is evident.
Apply to moist lawns when the soil temperature is above 12ºC (54ºF) and water them in well. The nematode needs to be washed well in so that they reach the roots where the leatherjackets will be. Make sure the lawn does not dry out after applying nematodes.
The nematode species, Steinernema feltiae, seek out the leatherjackets and attack the pest by entering natural body openings. The nematodes infect their host with a bacteria which stops the Leatherjackets from feeding, quickly killing them. The nematodes then feed upon the Leatherjackets, breeding and dispersing to encounter further Leatherjackets.
A product that is deemed for professional use can only be applied by someone that has the requisite Pesticide Application license. Chemical control can be implemented as soon as the problem has been identified, generally in October after the grubs have either come to the attention of predators that are damaging the surface or visible yellowing patches are evident. Chlorpyrifos is the active ingredient in Cyren. Chlopyrifos is a crystalline organophosphate insecticide that can be used on turf and also controls Frit Fly, although it needs to be applied when there is no danger of frosty weather. Cyren operates on the nervous system of the invertebrate through vapour, contact and ingestion of plants that have absorbed it.
Alternatively if an infestation is anticipated Imidacloprid, the active ingredient in Merit Turf, can be applied at the end of spring/beginning of the summer. Imidacloprid is a systemic insecticide belonging to the class of chemicals known as neonicotinoids that acts upon the nervous system of invertebrates. Merit Turf is also an effective control against Chafer grubs. The invertebrates come into contact with the active ingredient either through their skin or through ingestion.
The active ingredient in Provado Lawn Grub Killer is imidacloprid which is a systemic insecticide belonging to the class of chemicals known as neonicotinoids that acts upon the nervous system of invertebrates. Provado Lawn Grub Killer is also an effective control against Chafer grubs.
Apply in the early evening, and then water the product in. Mix 1 sachet (3g) with 9 litres of water in a watering can fitted with a coarse rose or a sprinkle bar and stir well. Use immediately. Apply evenly to the lawn over an area of 10 m2. Ensure the lawn is well watered to move the active ingredient through the thatch. 5 to 15 mm of rainfall is sufficient or 5 to 15 litres of water per square metre. Avoid over watering. Maximum concentration must not exceed 3g of product per 9 litres of water. Maximum use rate: 3g of product over 10 m2. Only to be used once per year.
The professional biological control is also available to domestic users: When you start to see the adult daddy-long-legs in your garden (towards the end of August) they will be laying eggs within the next few days. These will hatch quickly; therefore, aim to apply about a week to two weeks after you see the adults.
Apply to moist lawns when the soil temperature is above 12°C (54°F) and water them in well. The nematode needs to be washed well in so that they reach the roots where the leatherjackets will be. Make sure the lawn does not dry out after applying nematodes.
The nematodes, Steinernema feltiae, seek out the leatherjackets and attack the pest by entering natural body openings. The nematodes infect their host with a bacteria which stops the Leatherjackets from feeding, quickly killing them. The nematodes then feed upon the Leatherjackets, breeding and dispersing to encounter further Leatherjackets.