The pear psyllid, Cacopsylla pyricola, is an important pest on pear in England. In orchard trials in Kent, Anthocoris nemoralis usually prevented the psyllid from increasing to high densities, provided that the pesticides applied were not damaging to the predator. Only small numbers of A. nemoralis appeared to overwinter on the pear trees, and synthetic pyrethroid insecticides used at the ‘bud burst’ stage, before colonization by the predators, did not disrupt regulation of the psyllid by A. nemoralis, and were very effective at reducing psyllid numbers. These broad-spectrum pesticides were very damaging to predator populations if used later in the season, generally resulting in an upsurge of psyllid populations. Of the more selective materials tested for post-blossom use, amitraz was the most effective against psyllids, and was not damaging to predatory anthocorids. Diflubenzuron was also effective against psyllids, although slower acting, and caused only slight reduction in anthocorid density. Chemical control of scab and, when necessary, of mite, aphid and lepidopterous pests, can be compatible with the preservation of A. nemoralis; this is the basis of integrated pest management on pear.

An integrated pest management (IPM) programme for apple involving selective insecticides applied in response to monitoring and using non-acaricidal fungicides was compared with a routine ‘calendar’ broad-spectrum programme over a 5-year period. This IPM system optimized the effect of natural enemies. From the second season onwards the predacious phytoseiid mite, Typhlodromus pyri, reached sufficient numbers to regulate Panonychus ulmi at low, non-damaging numbers. T. pyri also suppressed apple rust mite, Aculus schlechtendali, over most of this period. No acaricides were required on the IPM plots in the last 3 years of the trial. Small reductions in the number of insecticide/acaricide applications were made on the IPM plots but insect damage to fruit, especially by lepidopterous larvae, was higher than on the broad-spectrum plots. Several pests now rarely seen in commercial orchards built up on IPM plots and required specific treatments. The results are discussed in relation to further development of a commercially applicable IPM system.

Damson-hop aphid, Phorodon humuli, is the major insect pest of English hops and has developed marked resistance to many organophosphates (OPs), and lower levels of resistance to other OPs, carbamates and endosulfan used as foliar sprays. Current control methods rest heavily on the systemic OP mephosfolan applied as a soil drench. After the persistent aphidical action of an early-season (May) soil drench of mephosfolan has declined, insect predators, particularly Anthocoris nemoralis and A. nemorum, can usually contribute greatly to control for the remainder of the season, especially within the hop cones. Means of suppressing aphids in July/August with minimum harm to predators are essential for a commercially feasible system of integrated control; possible methods of achieving this are discussed.

Journal Article Effect of Four Synthetic Pyrethroids on a Predatory Mite, Typhlodromus pyri , and Its Prey, Panonychus ulmi , on Apples in Southeast England Get access M. T. Aliniazee, M. T. Aliniazee 4 East Mailing Research Station, Kent, England 4 Permanent address: Dept. of Entomology, Oregon State Univ., Corvallis. The work was conducted during senior author's sabbatical leave at East Mailing Research Station. Search for other works by this author on: Oxford Academic PubMed Google Scholar J. E. Cranham J. E. Cranham East Mailing Research Station, Kent, England Search for other works by this author on: Oxford Academic PubMed Google Scholar Environmental Entomology, Volume 9, Issue 4, 1 August 1980, Pages 436–439, https://doi.org/10.1093/ee/9.4.436 Published: 01 August 1980 Article history Received: 18 December 1979 Published: 01 August 1980