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Apple Sucker (Psylla mali (Schmidberger))

Apple sucker wax

Honeydew and wax secreted by apple sucker nymphs

Apple sucker is generally a minor pest of modern desert and culinary apple orchards where it is controlled well by insecticide spray programmes. It is troublesome in unsprayed orchards, especially in organic orchards and on older trees.

It is an important and damaging pest in cider apple orchards.

The life cycle involves sucker eggs overwintering on bark before hatching at or shortly after bud burst when they invade the trusses.

The presence of the pest is indicated by blobs of waxy honeydew in the base of the trusses where the flower stalks join. Most damage is done by nymphs during the pre-blossom period.

They suck the sap from green tissue of blossom trusses and leaf buds causing brown discoloration of petals and blossom buds and, where damage is severe, buds may be killed. The discoloration resembles, and is sometimes mistaken for, frost injury.

Populations of apple sucker should be assessed along with other pests at the pre-blossom pest assessment. Examine trusses for signs of infestation or damage. The treatment threshold is 30% or more of trusses infested.

Control

Spray with an approved insecticide before blossom.

 

Insecticides approved for use on apple which are recommended by the manufacturer  to be effective or partially effective for control of apple sucker when applied to control other pests

Choice of insecticides – efficacy factors

Active ingredient Trade name (examples) Class Selectivity Approved for control of – Safety to Typhs 
cypermethrin various pyrethroid broad spectrum Aphids including woolly aphid, caterpillars, sucker,sawfly, capsids etc. harmful
deltamethrin Decis etc. pyrethroid broad spectrum Aphids, apple sucker, capsids, codling & tortrix moths, sawflies harmful
diflubenzuron Dimilin CSI selective Caterpillars, codling moth, earwigs, rust mite on apple and pear. (Also gives partial control of apple sawfly) safe

 

Choice of insecticides – Safety factors

Read and fllow the label before applying any sprays

Hazards2 Harvest interval(days)  Max. no. sprays Buffer zoneWidth (m)
Anticholin-esterase?  Humans Fish & aquatic life Bees
cypermethrin no h, i ed d 0 4 18
deltamethrin no h, i ed d 0 u 50
diflubenzuron no u d u 14 2 20
h=harmful, i=irritant, d=dangerous, ed=extremely dangerous, c=closed cab required for air assisted sprayers,u=uncategorised/unclassified/unspecified, sm -= statutory minimum (= 5 m buffer zone width)

Control in organic orchards

Generally, there are no satisfactory controls for apple sucker in organic orchards. Cultural control approaches should be given priority.Though not specifically recommended for control of apple or pear sucker, it is probable that early season sprays of fatty acids (Savona) will give some control of apple sucker.

  • The sprays have to be applied early at the green cluster growth stage (after the overwintered eggs have hatched in spring but before reproduction occurs is best) and in high volumes so that the suckers are thoroughly wetted by the spray.
  • Application is sometimes made during gentle rain.

 

Further reading