Leatherjackets Flashcards
What crops do the affect
Oilseeds, root veg, cereals lettuce
What are they the larvae of
Crane fly
Risk factors
Crops following grass
Cereal crops less likely to suffer damage once tillered
What can increase numbers
Prolonged damp conditions in late summer and early autumn increases leatherjacket numbers
Identification ?
Greyish black, tough skin plump and soft, can grow up to 40mm
Where do they feed
Feed just below the soil on roots and stems, but on warm damp nights they can feed on the surface and can cut stems off like cutworms
What can reduce numbers
Dry September weather because eggs and young leather jackets are vulnerable to desiccation
Why are crops at risk following grass
Larvae continue to feed in ploughed down turf moving on to feed on the new crop when the turf rots away leading to damage appearing weeks after emergence
What are the non chemical control methods 4 things
Cultivations decrease populations
Ploughing in July/ august before egg laying can limit attacks- but can increase wheat bulb fly
Thorough consolidation to minimise movement
Establishing vegetable brassicas later than mid June avoids damage to seedlings since main species stops feeding
monitoring
Assess leather jacket numbers before ploughing
Soil corer
20 cores for 4 ha
Soil to a lab
Other new way of monitoring
Blasdale apparatus drives leatherjackets into trays of water by heating the soil cores from above
Thresholds for spring cereals
50 per meter squared
Threshold for oilseeds
More than 50 per metre squares
