Cause damage to germinating and newly emerged seedlings
Very small brown insects about the size of a pin head
Jump when disturbed
Detected most easily by placing a white card or cloth on ground and gently disturbing soil.
Biology
Several species of springtails may cause damage to seedling brassica crops and they occur throughout New Zealand. Bourletiella hortensi is the most common. These are soft bodied insects varying in colour from brown to black and grow up to 1 mm in length. They are a type of Collembola commonly known as globular springtails. This name derives from them appearing to consist of two attached balls (hence globular) and a specialised appendage which enables them to spring very quickly into the air (hence springtail). They live on the soil surface and lay their eggs in the soil. Under moist conditions development is very rapid. Several generations are produced each year.
Impacts
Springtail mouth parts are adapted for chewing. Damage to brassicas and fodder beet may occur as soon as the seed coat is split and the cotyledons begin to emerge. This means that the seedlings are damaged before they emerge from the soil. Initially the stems are attacked but as the seedlings emerge from the soil scalloping of leaf edges, small pits and holes in the leaves become evident
Early detection or better still prediction of damage is necessary to avoid seedling loss.
Control
Routine spraying or using coated seed can be worthwhile but inspection of the soil to be sown should be undertaken especially if springtails have been a problem in the past. When preventative measures are not applied insecticide should be applied as soon as damage is noticed if it is significant. If the damage is only minor the plants may soon outgrow the impact of springtail feeding
Several insecticides are registered against springtails.
Insecticide
Application
Time of application
Imidaclopirid
Seed coating
At sowing
Chlorpyrifos
Spray
From sowing to emergence
Diazinon
Spray
From sowing to emergence
Dimethoate
Spray
From sowing to emergence
Fenitrothion
Spray
From sowing to emergence
Maldison
Spray
From sowing to emergence
Spinetoram
Spray
Apply during early post emergence
Terbufos
Granule
Drill with seed
Phorate
Granule
Drill with seed
Consult your farm consultant, industry representative or the New Zealand Agricultural Manual for more information about chemical control.